Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Research on improving magnetic field adaptability of high-precision IFOG
XU Bao-xiang, XIONG Zhi, HUANG Ji-xun, YU Hai-cheng
Accepted Manuscript  doi: 10.3788/IRLA20200239
[Abstract](53) [FullText HTML](26)
The magnetic non-reciprocity error is one of the main factors that restrict the application of high-precision IFOG, and the error is related to the strength of magnetic field and the twist rate of fiber. The magnetic field sensitivity of fiber coil is more than 10° / h / GS due to the twisting of the fiber, even if permalloy is used to shield the magnetic field, the shielding effectiveness can only reach about 30 dB, which cannot meet the requirements of high-precision IFOG. The influence of the connection gap between shielding materials on shielding effectiveness is analysed by an equivalent circuit model and finite element simulation, the influence of the twist rate on the magnetic field sensitivity is deduced by formula. Through these analyses, the improvements that changed the connection of shielding materials from screw connection to laser welding and made the fiber de-twist are proposed. Through the measure of fiber de-twist, the magnetic field sensitivity of the fiber coil is reduced by 89.3%; through the improvement of laser welding, the shielding effectiveness is improved from 31 dB to at least 64 dB, the magnetic field sensitivity is reduced from 0.0265°/h/Gs to less than 0.0004°/h/Gs, and the bias stability of the IFOG in different temperature is improved by more than 7.5%. These improvements can improve the precision of the fiber coil in the magnetic field and temperature environment.
Signal processing method for shaped pulse and analysis of radiation flux deviation in low temperature
DU Hua-bing, SUN Ao, SHANG Wan-li, HOU Li-fei, CHE Xing-sen, YANG Yi-meng, YANG Guo-hong
Accepted Manuscript  doi: 10.3788/IRLA20200181
[Abstract](69) [FullText HTML](39)
Flat response X-ray diodes have been widely used in large-scale laser devices at home and abroad for the measurement of angularly distributed X-ray radiation flux. In practical experiments, flat-response X-ray diodes measure radiation flux images that have a step change in a shaped pulse-driven radiation source. In order to ensure a good signal-to-noise ratio, a single signal will be connected to multiple channels of the oscilloscope, and then the signals of different channels will be processed, and the final image with good signal-to-noise ratio will be stitched. The research in this paper mainly introduces this data processing method and gives theoretical calculations. At the same time, a theoretical approximation and numerical simulation of a deviation in the calculation of the low temperature radiation flow reduction are made, and the relative uncertainty of the deviation is obtained. Coupled with the uncertainty of all factors, the curve of the overall uncertainty of the flat-response X-ray diode as a function of the radiation temperature is obtained, which realizes precise diagnosis and completes the experimental needs for diagnosis.
Random laser radiation behavior of liquid crystal in photonic crystal fiber carrier
Wu Rina, Song Yunhe, Lu Jiaqi, Gao Rui, Li Yeqiu, Dai Qin
Accepted Manuscript  doi: 10.3788/IRLA20200171
[Abstract](68) [FullText HTML](61)
A hollow-core photonic-crystal fiber filled with a mixture of nematic liquid crystal TEB30A, chiral agent S-811 and laser dye PM597 is pumped by a frequency-doubled Nd: YAG laser with a wavelength of 532 nm. The laser emission spectra is measured and the random laser radiation behavior in the photonic-crystal fiber carrier is investigated. When side-pumping is applied to the fiber, the emitted random laser with a wider radiation direction from the side face has a wavelength range of 590−605 nm and an FWMH of 0.3 nm. When end-pumping is employed to the fiber, the emitted random laser from the end face has a wavelength range of 580−605 nm and an FWMH of 0.3 nm. After the sample is heated to the isotropic temperature, the laser emission with both pumping methods is shut down. The experimental results demonstrate that the dye doped liquid crystal mixture in the micropore induce the random laser emission in the photonic-crystal. The change in the mean free path of photon transport and the fluctuation of the dielectric tensor of chiral nematic liquid crystals with temperature are the main factors affecting the laser intensity.
Development of beam brightness enhancement based on diamond Raman conversion
BAI Zhen-xu, CHEN Hui, LI Yu-qi, YANG Xue-zong, QI Yao-yao, DING Jie, WANG Yu-lei, LÜ Zhi-wei
Accepted Manuscript  doi: 10.3788/IRLA20200098
[Abstract](698) [FullText HTML](605)
High brightness laser sources with different wavelengths play an important role in the fields such as military, industrial, and life sciences etc. However, due to the intrinsic spectral and thermophysical properties of current available laser gain materials, it is difficult to take into account the wavelength and output power of the traditional inversion lasers, which even leads to the decrease of beam brightness. To overcome this problem, beam cleanup by using nonlinear optical technology have been carried out in recent years, which is directly transferring the low-quality beam generated from inversion lasers into high-beam quality through the effects such as stimulated Raman or Brillouin scattering. Among them, with excellent properties such as high Raman gain coefficient, high thermal conductivity and wide spectral transmission range, diamond exhibits excellent beam brightness enhancement characteristics while realizing high efficiency Raman conversion, which provides a new technical path to generate high power and high brightness laser beam. Here, the development of brightness enhancement based on first-order and cascaded Raman conversion of diamond is reviewed, and its future applications are discussed.
Development of Coaxiality Measurement System of Turbine Components and Stud Standard Parts
Zhang Bo, Zhang Wengjian, Lei Lihua
Accepted Manuscript  doi: 10.3788/IRLA20200216
[Abstract](60) [FullText HTML](34)
Turbocharger and gearbox were widely used in the precision machinery manufacturing industry. The dimensional accuracy of Turbo parts and stud standard parts was an important guarantee for the assembly accuracy of Turbo parts and gearbox, among which coaxiality was a key parameter for the dimensional accuracy of Turbo parts and stud standard parts. According to the demands of coaxiality measurement for turbine components and stud standard parts, a set of checking fixture was developed, and a software based on LabVIEW was built for the measurement. The coaxiality of stud standard M12 was measured by experiment and the uncertainty of measurement was evaluated. The experimental results show that the coaxiality error obtained from the four measurements is 6.3–6.5 μm, and the extended uncertainty reaches 2.6 μm. The results show that the developed coaxiality measurement system is suitable for the high precision measurement of the coaxiality of turbine parts and stud standard parts.
Research on ultra-low power consumption methane detection system based on NDIR technology
Zhao Qingchuan
Accepted Manuscript  doi: 10.3788/IRLA20200140
[Abstract](47) [FullText HTML](41)
In order to meet the needs of low power consumption methane detection technology, an ultra-low power consumption infrared methane sensor and system based on non-dispersed infrared spectroscopy is developed, which is based on the characteristics of methane gas molecules having main absorption peak in the infrared band of 3.2 μm~3.4 μm. The selection of LED and PD devices and the design of optical path are studied based on the analysis of the principle of infrared differential detection. The power consumption of infrared methane sensor is reduced to 10 mW by using LED packets of pulses current drive technology. The influence of temperature change on the measurement of methane concentration is studied by experimental method, the temperature compensation algorithm formula is obtained by data analysis and linear fitting of normalization method. The performance experiment is carried out on the detection system platform, and the basic performance parameters are given. The system has the advantages of low power consumption, anti-interference of water vapor and good detection stability, and has important application value.
Influence of Gaussian mirror parameters on LD-pumped Nd:YAG laser
MENG Pei-bei, SHI Wen-zong, JIANG Shuo, QI Ming, DENG Yong-tao, LI Xu
Accepted Manuscript  doi: 10.3788/IRLA20200127
[Abstract](40) [FullText HTML](24)
The influence of eccentricity and laser performance of LD-pumped Nd:YAG laser was investigated experimentally at different parameter Gaussian mirrors. Largest energy, narrowest width and smallest divergence can be obtained simultaneously only when the optical axis, laser crystal axis and Q-switch axis were in agreement, furthermore the optical axis went through the reflectivity center of Gaussian mirror. When eccentricity appeared, the energy, pulse width and divergence degraded more with smaller reflectivity radius or larger center reflectivity of Gaussian mirror. For 2.5 mm reflectivity radius and 30% central reflectivity Gaussian mirror, energy decreased 7%, pulse width increased 33%, and divergence increased 20% under 0.5 mm eccentricity. For laser performance, the smaller the reflectivity radius or center reflectivity of Gaussian mirror, the better the beam quality and the smaller the optical-to-optical efficiency. Considering the eccentricity influence and laser performance, 2.75 mm reflectivity radius and 20% center reflectivity Gaussian mirror was optimum. When the pump energy was 984 mJ, output energy of 128 mJ, pulse width of 7.3 ns, and beam quality M2 factor of 4.6 at 1064 nm were achieved, corresponding to the optical-to-optical efficiency of 13%. The experimental results in this paper can be a reference of the laser design and alignment.
Star Map Recognition Method of L2 Normal Distance
Wang Zewen, Wang Guangjun, Liu Xiaobo, She Jinhua
Accepted Manuscript  doi: 10.3788/IRLA20200040
[Abstract](29) [FullText HTML](28)
Based on the Hausdroff distance, this paper presents a star map recognition method that does not depend on the rotation direction and focal length of the star sensor. When constructing the data point set of Hausdroff distance, this paper uses the relative Euclidean distance corresponding to norm L2 as the set element to solve the influence of star sensor rolling angle on star pattern recognition. On the other hand, due to the influence of the focal length of star sensor, there are errors between the star sensor image and the standard reference image. When constructing standard data point elements, consider that if a data point set contains another data point set, the L2 normal distance between at least two data points between the two data point sets is the same. Therefore, the relative distance is scaled, and the relative spatial distance in each set is divided by the smallest relative spatial distance in the set to form a new set of data points. This method is not necessary to calibrate the star sensor image due to different focal lengths influence. The paper presents the calculation formula and implementation steps and the simulation results. The experimental results show that the algorithm can obtain the star map recognition results correctly and get the attitude information of star sensor in the case of star sensor rotation, scale transformation, etc.
Effect of aspheric particles on laser polarization characteristics
ZHAN Jun-tong, ZHANG Su, Fu Qiang, Duan Jin, Li Ying-chao,
Accepted Manuscript  doi: 10.3788/IRLA20200150
[Abstract](14) [FullText HTML](41)
The polarization scattering characteristics of spherical particle swarm have been studied, but in the real environment, the shape of particles is non-spherical, and the multiple scattering polarization characteristics of non-spherical particles have not been obtained. In this paper, the aspheric particle scattering model is improved based on the T matrix calculation method to obtain the scattering amplitude matrix of aspheric particles. Analyzing the influence of different horizontal and vertical axis ratios, shape and wavelength on the polarization characteristics of ellipsoidal particles, cylindrical particles and Chebyshev particles by computer simulation. The results showed that: for ellipsoid particles, the maximum polarization degree changed from 130° to 90° after the eccentricity changed from 2 to 3, and the polarization degrees of 450 nm, 532 nm and 671 nm increased by 50%, 25% and 24% respectively. Cylindrical particle long and short axis interchange has little effect on the change of polarization. The surface irregularity of chebyshev particles changed from 3 to 8, the polarization degree increased by 18%. The research results provide a theoretical basis for the multiple scattering characteristics of the aspheric particle group, finally solve the problem of the difference in polarization transmission characteristics between the real environment and the ideal environment.
An Optical Design of a Laser Tracker
JI Xiaohui
Accepted Manuscript  doi: 10.3788/IRLA20200088
[Abstract](1179) [FullText HTML](477)
In order to improve the search range and imaging resolution of the ground target by the laser tracker, a method of searching and tracking the target with a common aperture laser tracker under an airborne platform is presented and the optical system is designed. The laser tracker is fixed on the aircraft by strap down, it improves its stability. The R-C reflection telescopic system with common aperture is adopted to emit the laser and receive laser echoes, which reduces the overall size and improves the imaging resolution. The scanning search target is realized by double optical wedge component, and the search frequency is increased and the search field of view is enlarged. The relationship between the rotation angle of double optical wedge and the angle of outgoing optical deflection is given. The design results show that when the aperture of the system is φ300 mm and the focal length is 2100 mm, the overall size is 685 mm, the search and scan field of view is ±5°, the imaging field is ±0.08°, the maximum size of the imaging spot speckle is 2.417 μm, and the MTF value of the system is greater than 0.4 at 50 lines per millimeter, which meets the imaging requirements. When the target distance is three kilometers, the searchable range reaches 526 meters, and the four-meter-sized target can be recognized with a imaging resolution of two seconds.
1 123 nm Q-switched Nd: YAG laser based on gold nanocages and MoS2 saturable absorbers
Zhang Bin, Li Ying, Liu Binghai
Accepted Manuscript  doi: 10.3788/IRLA20200084
[Abstract](363) [FullText HTML](272)
Based on gold nanocages (GNCs) and MoS2 as saturable absorber (SA), respectively, passively Q-switched Nd: YAG lasers at 1 123 nm were demonstrated. When Q-switched laser with GNCs as SA, Q-switched pulse with the shortest pulse duration of 253 ns and maximum pulse repetition rate of 326 kHz was achieved under the pump power of 6.04 W with the maximum average output power of 221 mW. Compared with the experimental results of MoS2 Q-switched laser, the gold nanocage Q-switched laser has higher output power and efficiency, narrower pulse width and higher repetition rate. These results indicated a great potential of the GNCs film as SA in the near-infrared region.
Powerful iodine stabilized He-Ne laser as wavelength reference
WANG Jian-bo, YIN Cong, SHI Chunying, WANG Hanping, CAI Shan,    
Accepted Manuscript  doi: 10.3788/IRLA20200111
[Abstract](970) [FullText HTML](425)
In order to meet the requirement of high output power of the laser monochromatic light source in the precision measurement, a high-power iodine stabilized He-Ne laser system with a fully enclosed, integrated structure was developed. The principle of saturation spectral detection, the method of absorption peak recognition and locking and the frequency stability of iodine stabilized laser were studied. Firstly, the basic principle of detecting saturation absorption spectrum of iodine molecular using the three harmonic method was introduced, and its mechanism of eliminating the power background was analyzed. Then, the stability of the integrated resonant cavity in the iodine stabilized laser was demonstrated, and the effects of axial expansion and lateral asymmetric deformation on the output power were discussed in detail. After that, the correspondence between the profile of laser output power and the iodine molecular saturation absorption peaks was presented, the feasibility of using the secondary harmonic signal to achieve absorption peak recognition was introduced, and the long-term locking ability of high-stability resonant cavity was demonstrated. Finally, the wavelength stability and reproducibility of high-power iodine stabilized He-Ne laser were analyzed. The experimental results shown that the standard deviation for the frequency jitter of high-power iodine stabilized He-Ne laser was 33 kHz, the stability at 1000 s and the reproducibility in three months were 4.1×10−13 and 3.3 kHz (7.0×10−12), respectively. Its absolute frequency was 3.0 kHz lower than the recommended value by the International Committee for Weights and Measures (CIPM).
Energy control algorithm of high frequency KrF excimer laser
Feng Zebin, Zhou Yi, Jiang Rui, Han XiaoQuan, Sun Zexu, Zhang Hua
Accepted Manuscript  doi: 10.3788/IRLA20200043
[Abstract](463) [FullText HTML](313)
Energy stability and dose accuracy are important indicators of high-repetition frequency excimer lasers for semiconductor lithography, which must be controlled by high-precision control algorithms. For the purpose of energy characteristic control, during the design of the algorithm, firstly, the single-pulse energy characteristics of the excimer laser were analyzed. Base on the analysis, a simulation model of the output energy of the excimer laser was established and had been experimentally proven to be effective. Then, the energy stability control algorithm, the double closed-loop dose accuracy control algorithm based on PID and the dose accuracy control algorithm based on decision algorithm were designed respectively and the control effects of the algorithms were tested separately on the simulation model. The simulation analysis results showed that the dose accuracy control algorithm based on the decision algorithm was more adaptable. The algorithm base on decision was validated on a KrF excimer laser with a repetitive frequency of 4 KHz. Controlled by the algorithm, the 3σ of laser energy stability less than 5% and the dose accuracy less than 0.4%, which satisfied the requirements of semiconductor lithography. The effectiveness of the energy characteristic control algorithm in the research had been proved in both simulation and actual experiments.
Development of solid-state high voltage switch for pulsed gas laser
Yang Yinhui, Zheng Yijun, Zhu Ziren, Sun Ke, Tang Huajiang, Tan Rongqing, Su Xinjun
Accepted Manuscript  doi: 10.3788/IRLA20200045
[Abstract](34) [FullText HTML](30)
A solid-state high voltage switch for pulsed gas laser based on magnetic pulse compression system is developed experimentally. In the experiment, the output efficiency of the magnetic compression switch is maximized by adjusting the reset current and load resistance. After compression by two-stage magnetic switch, the pulse width is about 5% of the original. The rising time after compression is about 180 ns, and the amplitude is about 16 kV. The first-stage magnetic compression efficiency is 89.2%, the second-stage magnetic compression efficiency is 97.7%, and the total compression efficiency reached 87.2%. After receiving the laser, measured output laser pulse energy is about 20 mJ, the output laser pulse half-height and width are about 85 ns.
Development on High Precision CO2 Isotope Measurement System Based on Infrared TDLAS Technology
Hou Yue, Pengquan Zhang, Guanyi Yu, Huang Kejin
Accepted Manuscript  doi: 10.3788/IRLA20200083
[Abstract](983) [FullText HTML](439)
For natural gas distribution monitoring, it is very important to measure the CO2 isotope with high precision. In this paper, the tunable diode laser absorption spectrum (TDLAS) technology is adopted to realize the high precision CO2 isotope measurement through the absorption spectrum line of 13CO2/12CO2 at 4.3 μm. The measurement system consists of a mid-infrared interband cascade laser (ICL) operating in a continuous wave mode, a long-path multipass cell (MPGC) and a mid-infrared mercury-cadmium telluride (MCT) detector. Aiming at the problem that the intensity of 13CO2 and 12CO2 absorption spectra is affected by the temperature, an MPGC high precision temperature control system is developed. In the experiment, five CO2 gases of different concentrations are configured to calibrate the measurement system, and the response linearity is up to 0.9996. The results show that when the integral time is 92 s, the isotope measurement precision is as low as 0.0139‰, which has practical application value.
Image clarification and Point cloud calculation under turbulence by light field camera
Zhang Xuanzhe, Wang Yan, Wang Jiahua, Hou Zaihong, Du Shaojun
Accepted Manuscript  doi: 10.3788/IRLA20200053
[Abstract](1121) [FullText HTML](567)
Image clarification and Point cloud calculation under turbulence is finished, by Improved information extraction algorithm of light field camera, based on phase space optics. This algorithm is more fully to use RAW data, because of adopting four dimensional density function to describe the structure of compound eye, and therefore, it can resist the influence of turbulence on local sub-aperture images, acquiring target point cloud steady, calculating the depth map and clarifying turbulence-degraded image. Light field camera based on such method acquire more than 4 k accurate wavefront distribution, when used for detection of indoor target behind the turbulence pool and outdoor target 500 m far from the camera, and outputting 3D point clouds and clear image successfully for both of them.
Hybrid phase retrieval with chromatic dispersion in single-lens system
Cheng Hong, Liu Yong, Hu Jiajie, Zhang Xiaolong, Deng Huilong, Wei Sui
Accepted Manuscript  doi: 10.3788/IRLA20200017
[Abstract](592) [FullText HTML](541)
Phase retrieval is to recover the original phase information by using the intensity information obtained from observation. Transport of intensity equation (TIE), as a traditional non-interference phase retrieval technique, can compute the losing phase information from only a minimum of two intensity measurements at closely spaced planes by solving the equation. This method usually requires the acquisition of intensity images by moving the object to be tested or CCD, which inevitably results in mechanical errors. A new phase retrieval method called chromatic dispersion-hybrid phase retrieval(CD-HPR) is proposed. The object is imaged at the same position by setting different wavelengths of light after passing through the single-lens system, in-focus and defocus intensity images are obtained without mechanical movement, and the initial phase information of an object is calculated from the phase retrieval technique based on TIE by combining the relationship between the defocus amount and the wavelength. Next angular spectrum iteration is used to improve the initial phase information. In this simulation, the RMSE between the phase recovered by this method and the original phase is 0.1076. At the same time, the phase of the lens array was restored by experiment. The error between the experimental result and the real parameter is 3.4%, which proves the correctness and effectiveness of the proposed method. This method extends the limitation of the traditional method that requires the light source to be monochromatic and improves the calculation accuracy.
Accepted Manuscript
[Abstract](2846) [FullText HTML](827)
Depolarization Mechanism and Compensation Scheme of Radially Polarized Beams
YANG Ce, PENG Hong-pan, CHEN Meng, MA Ning, XUE Yao-yao, DU Xin-biao, ZHANG Xie
Accepted Manuscript  doi: 10.3788/IRLA202049.20200038
[Abstract](644) [FullText HTML](1796)
Depolarization mechanism and compensation scheme of radially polarized beams under non-uniform pumping are investigated. Theoretical analysis shows that, for the non-uniform pumping status, the thermal induced shear birefringence caused by the thermally induced shear stress within the cross-section of the isotropic crystal is the main reason for the depolarization of the radially polarized beams. Related experiments were designed to evaluate the depolarization of the radially polarized beams which under non-uniform pumping conditions by using two methods of thin-film polarizer (TFP) measurement and purity measurement, in which the TFP measurement method is used to detect the overall depolarization of radially polarized beams and the purity measurement method is used to detect local depolarization of radially polarized beams. With a peak pump power of 1.1 kW, the depolarization measured by the two evaluation methods is 2.34% and 2.53%, respectively. Based on the theoretical analysis and evaluation results, a combination of phase modulation and spatial mode matching was considered in the design of the depolarization compensation scheme, which improved the depolarization of the radially polarized beams by 59%. Meanwhile, a picosecond radially polarized beam with a pulse energy of 19.36 mJ, a purity of 90.13%, and a beam quality M2 factor of 3.8 was achieved.
Picosecond multi-pulse burst pump KGW infrared multi-wavelength Raman generator
YANG Ce, CHEN Meng, MA Ning, XUE Yaoyao, DU Xinbiao, JI Lingfei
Accepted Manuscript
[Abstract](2844) [FullText HTML](770)
Picosecond infrared multi-wavelength Raman generator which adopted multi-pulse pumped KGW scheme was reported. A mathematical model was developed to investigate the effect of multi-pulse burst pumping regime on the vibrational mode of the Raman active molecule. The simulated results show that the response oscillation of the Raman active molecule to the multi-pulse burst pumping regime is more active and durable compared with the traditional single pulse pumping regime, which promotes the weakened molecule oscillation to return the natural frequency multiple times. The enhancement effect is beneficial to improve the Raman gain, reduce the Raman threshold, and increase the Raman conversion efficiency. During the experiment of picosecond multi-pulse pump KGW Raman crystal, the three-pulse burst pumping regime improves the Raman gain more than two times, reduces the threshold of stimulated Raman scattering more than 50%, and increases the Raman conversion efficiency more than 16% for 768 cm–1 Raman mode and 22% for 901 cm–1 Raman mode. Based on the three-pulse burst pumping regime, a 1 kHz mJ-level picosecond infrared multi-wavelength Raman generator was designed, which achieved the pulse energy of 1.39 mJ, the maximum Raman conversion efficiency of 29.6% for the 768 cm–1 vibrational mode of KGW, and the pulse energy of 1.38 mJ, the maximum Raman conversion efficiency of 25.7% for the 901 cm–1 vibrational mode of KGW. In addition, the Raman laser can radiate up to eight infrared Raman lines simultaneously for both the two vibrational modes of the KGW crystal, which covers the range of 800–1 700 nm.
Numerical study on backward light amplification and damage in high-power fiber laser
Sheng Quan, Si Hanying, Zhang Haiwei, Zhang Junxiang, Ding Yu, Shi Wei, Yao Jianquan
Accepted Manuscript
[Abstract](3917) [FullText HTML](2067)
The amplification of both continuous-wave (CW) and pulsed backward signal in high-power master-oscillator-power-amplifier based fiber laser are investigated using rate equation model. The results show that the CW backward light would be amplified significantly by the high-power amplifier and thus decrease the laser output seriously. For the pulsed backward signal, the pulse energy would not be amplified obviously since the energy storage is absent in CW fiber laser. Considering the damage threshold of the fiber and devices including end-cap and fiber Bragg grating (FBG), the amplification of CW backward light may damage the FBG of the laser oscillator, and the backward laser pulse with millijoule level pulse energy may damage the fiber, while there also exists the risk of end-cap damage when pulsed backward laser incidents.
Effects of gain distribution on self-similar amplification of picosecond pulses
Zhang Yun, Liu Bowen, Song Huanyu, Li Yuan, Chai Lu, Hu Minglie
Accepted Manuscript
[Abstract](5042) [FullText HTML](2205)
The effects of gain distribution on self-similar amplification of picosecond pulses in a Yb-doped fiber laser system are studied by numerical simulation. Ultrashort laser pulses amplified in self-similar amplification theoretical model is established to analyze the impact of pump configuration, fiber length and total gain coefficient on the self-similar amplification evolution and laser output performance. Detailed numerical simulation reveals that the best self-similar amplification result can be found for different cases, where high-quality self-similar pulses with ~100 fs transform-limited pulse duration are obtained. It is demonstrated that the self-similar evolution speed in a forward-pumping scheme is faster than that in a backward-pumping scheme for a fixed seed pulse. Furthermore, the results indicate that for the self-similar amplifier with different fiber lengths and gain coefficients, the forward-pumping scheme shows better evolution results in lower seed energy and longer wavelength range, while the backward-pumping scheme is more suitable for the higher seed energy and shorter wavelength range.
Thermal damage of monocrystalline silicon irradiated by long pulse laser
Guo Ming, Zhang Yongxiang, Zhang Wenying, Li Hong
Accepted Manuscript
[Abstract](37) [FullText HTML](52)
In view of the thermal damage law and mechanism of monocrystalline silicon for millisecond pulsed laser, the temperature of monocrystalline silicon irradiated by millisecond pulsed laser is measured by high precision point temperature meter and spectral inversion system. Then the temperature evolution process is analyzed. Also, the temperature state during the whole process of thermal damage of monocrystalline silicon irradiated by millisecond pulsed laser and the corresponding damage structure are studied. The results of this study show that the peak temperature of laser-induced monocrystalline silicon increases with the increase of energy density when the pulse width is fixed, When the pulse width is between 1.5 ms-3.0 ms, The temperature decreases with the increase of pulse width. Temperature rise curve shows inflection point when it is close to the melting point (1687 K), the reflection coefficient is from 0.33 to 0.72. During the gasification and solidification stages, it also shows the gasification and the solidification plateau periods. Thermal cleavage damage of monocrystalline silicon precedes thermal erosion damage. Stress damage dominates under low energy density laser irradiation, while thermal damage dominates under high energy density laser irradiation. The damage depth is proportional to the energy density and increases rapidly with the increase of the number of pulses.
Design of hybrid refractive-diffractive infrared dual-bandzoom optical system
YANG Hong-tao, YANG Xiao-fan, MEI Chao, CHEN Wei-ning
Accepted Manuscript  doi: 10.3788/IRLA20200036
[Abstract](515) [FullText HTML](423)
In this paper, the influence models of different diffraction elements on diffraction efficiency are established, and the diffraction efficiency among single diffraction element, harmonic diffraction element and double diffraction element was compared. The advantages of using double diffraction elements in infrared optical system are analyzed. The average diffraction efficiency of different material combinations is calculated. Based on this, a hybrid infrared dual-band and dual-field optical system suitable for airborne platform is designed. The resolution of the large field of view is 1.5 m@16 km.The long and the short focal length are 960 mm and 480 mm respectively. The zoom function is realized by switching the mirror to ensure the optical axis stability. The simulation results show that the MTF curves are smooth and close to the diffraction limit under the large temperature difference of −40 ℃~60 ℃.The RMS radius is within the radius of airy spots, and the minimum characteristic size of the binary diffraction surface is 6.9 μm. The design results meet the engineering requirements.
Incoherent digital holographic color imaging with high accuracy of image registration
Ren Hong, Bu Yuan-zhuang, Wang Xi, Li Yu, Du Yan-li, Gong Qiao-xia, Li Jin-hai, Ma Feng-ying, Su Jian-po
Accepted Manuscript  doi: 10.3788/IRLA20200022
[Abstract](916) [FullText HTML](857)
Fresnel incoherent correlation holography is a new technology which can record incoherent object holograms and has important applications in biomedical imaging and 3D remote sensing. The problem of image fusion registration in hyperspectral imaging, Three groups of double lens phase masks with constant focal lengths at 492 nm, 562 nm and 672 nm are designed and fabricated. The spatial light modulator calls the masks of three wavelengths in turn and records the holograms of the objects under the corresponding wavelengths, which owe to the spatial light modulator are programmable. Because of the three-color recorded light is modulated by the corresponding wavelength mask, the spot position size of the CCD surface is the same. The reconstructed images have constant lateral magnification, which can improve the image registration accuracy and avoid complicated spatial registration algorithm of spectral images. The system truly achieves high-precision registration and real-time fusion of holographic color imaging. The color 3D image obtained from the dice holograms has high color reconstruction after numerical reconstruction and color fusion.
Lasers & Laser optics
Optical design
Vibration isolation system for transportation of main mirror of a large Antarctic telescope
Yue Zhongyu, Cui Xiangqun, Gu Bozhong
2020, 49(9): 20190517.   doi: 10.3788/IRLA20190517
[Abstract](48) [FullText HTML](46) [PDF 2287KB](4)
The Antarctic Observatory of China contains an optical/infrared telescope with a diameter of 2.5 m primary mirror. The telescope is made in China and needs to be transported to the Antarctic Observatory in the form of large assembly. From Zhongshan Station in the edge of the Antarctic continent to Kunlun Station in the interior of the continent, the telescope needs to be transported by sled, which vibrates violently in some regions. In this paper, the vibration isolation system of the telescope's 2.5 m primary mirror module for transportation was researched. Firstly, the theoretical model of vibration isolation system was established and the performance of two-stage vibration isolation system was analyzed by the four-terminal parametric method. Secondly, the historical data from the Antarctic inland expedition team in the sled transportation was studied and the allowable dynamic condition of the primary mirror module was calculated by finite element method(FEM) considering the non-uniformity of the bottom supporting force. Thirdly, a two-stage vibration isolation system consisting of a leverage buffer structure and a polyethylene foam structure was proposed. Finally, the performance of this vibration isolation system was researched with FEM simulation and multi-body system simulation. The results show that the vibration isolation system proposed in this paper can meet the requirement of the mirror's transportation. In the finite element model, when the most extreme impact signal is loaded which is acquired by the Antarctic inland expedition team form the sled transportation, the maximum acceleration of the primary mirror module is less than 5 times acceleration of gravity which is a security value coming from the dynamic analysis of primary mirror module, and the Z-direction moving range of the module is about 1.2 m. So the vibration isolation system has practical value. This system can be used in the transport of the primary mirror module of the 2.5 m telescope to the Antarctic inland. The vibration isolation system proposed in this paper is valuable for transportation of other fragile structures.
Optical system design of star sensor with long focal length and athermalization
Wu Yanxiong, Qiao Jian, Wang Liping
2020, 49(9): 20200061.   doi: 10.3788/IRLA20200061
[Abstract](94) [FullText HTML](61) [PDF 1643KB](12)
Optical system is the core component of autonomous navigation star sensor to realize the collection of star light and high-precision attitude measurement. In this paper, the optical system of high precision star sensor was taken as the research object, the influence mechanism of the accuracy of optical system for detecting different color temperature stars were studied and analyzed. It is difficult to suppress the centroid drift caused by the changes of star color temperature and ambient temperature through later calibration, which needs to be controlled under the stage of optical design. The calculation model and allocation method of optical system design wavelength weight were established, and the performance evaluation was carried out. In addition to the conventional energy concentration, distortion and asymmetric aberrations, the centroid drift of star color temperature and ambient temperature change were proposed as the main index of accuracy evaluation. According to the application requirements, a long focal star sensor optical system based on space satellite platform was designed, with the focal length of 95 mm, the relative aperture of f 2.4, the field view of 8°× 8°, the spectrum range of 450-1 000 nm, and the energy concentration of more than 85% in 3×3 pixels. Based on the regular glass materials, the lateral color aberration of the optical system was corrected under ultra-wide spectral range and long focal. The lateral color aberration of the full field was less than 0.9 μm; The results of accuracy analysis show that the accuracy of centroid position is less than 0.36 μm in the range of 2 600-9800 K, and the change of focal length is less than 2.7 μm in the range of 0-40℃, and the accuracy of centroid position caused by temperature is less than 0.45 μm.
Design and realization of light and small long-wave infrared optical system
Hao Siyuan, Xie Jianan, Wen Maoxing, Wang Yueming, Yuan Liyin
2020, 49(9): 20200031.   doi: 10.3788/IRLA20200031
[Abstract](22) [FullText HTML](8) [PDF 1379KB](12)
The requirements on its load volume and weight are strict for unmanned airborne photoelectric pod. In order to meet the needs of 8-12.5 μm infrared detection, a lightweight and compact long-wave infrared optical system was designed and realized. The F number of the system was 2, the diameter was 150 mm, and the total field of view was 2.34 °. A twice focusing reflection-refraction structure was used as the optical system structure. It simplified the commonly used Cassegrain-type main system into a folded Newton-type main system, and simplified the spherical secondary into a plane mirror folding optical path. The off-axis aberrations were corrected by the aspherical correction lens group. An all-aluminum optical-mechanical structure was designed for the main system, combined with the optical-mechanical material matching of the rear optical path. In the temperature range of the working environment, the designed MTF of the system was more than 0.41@17 lp/mm, with 100% cold stop efficiency, and the volume was only Φ152 mm×125 mm. After final alignment, the MTF of the instrument was more than 0.24@17 lp/mm, and the image quality was clear and met expectations. The optical system was smartly designed, so the structure was light and compact, and the cost of manufacture and alignment was low. The design ideas and development methods can provide a reference for the optical systems of long-wave infrared instruments of unmanned airborne photoelectric pods for similar applications.
Control method of adaptive optical system based on conjugate combined model of aberration
Yong Jiawei, Guo Youming, Rao Changhui
2020, 49(9): 20190534.   doi: 10.3788/IRLA20190534
[Abstract](4343) [FullText HTML](1202) [PDF 2252KB](37)
In the concentric aperture circle of the unit circle, some special Zernike modes have interrelated relationship. When the modes with strong negative correlation is superposed with a certain coefficient, the aberrations in a certain concentric aperture will cancel each other and the wave surface will become smoother. This phenomenon is called the conjugate property between modes. In this paper, a set of distorted wavefront was set up, and the residual error was corrected by adaptive optical system. Then Zernike polynomials were used to decompose the corrected residual of deformable mirror. Through analysis, it was found for the first time that there was an obvious negative correlation between the lower and higher order aberrations in the residual wavefront with large mean square error. The aberration coefficients of the two parts will change regularly with the adjustment of the control signal of the deformable mirror, and in a certain combination of the coefficients, the two parts of aberrations will show conjugation. Based on the above research results, a control method was proposed. By optimizing the control voltage of the deformable mirror, the shape of the mirror surface can be adjusted so that the low-order and high-order aberration coefficients in the residual error can achieve the best matching. In this way, the root mean square (RMS) of the aberration in the concentric aperture circle of the pupil can be reduced, and the imaging quality of the system within this aperture range can be improved. The point target imaging and extended target imaging were simulated respectively. The results show that compared with the traditional closed-loop conjugate correction method, this method can obtain better optical imaging quality in the face of complex aberrations, and can effectively expand the application range of traditional adaptive optical system. This control method has a good application prospect when the deformable mirror has large fitting residual.
Development of pressure control system for laser infrared multipass cell using Ziegler-Nichols-PID algorithm
Xu Huixiang, Kong Guoli
2020, 49(9): 20190551.   doi: 10.3788/IRLA20190551
[Abstract](17) [FullText HTML](10) [PDF 1403KB](5)
In order to realize the high performance detection of CO2 gas isotope, a multi-pass gas cell pressure control system with high precision and stability was developed in this paper. In terms of hardware, the pressure sensor was connected to the front and back end of the multi-pass gas cell to measure the inside pressure of multi-pass gas cell. The main controller regulated the proportional valves that were at the front and back end of the multi-pass gas cell via PWM signal, so as to realize the closed loop of pressure control. In terms of software, Ziegier-Nichols engineering setting method was adopted to determine three parameters P, I and D. The results show that the control accuracy is ±0.04 Torr (1 Torr=133.322 Pa) when the pressure of the multi-pass gas cell is 60 Torr. In experiment, the developed pressure control system of multi-pass cell was used to measure the absorption spectra of 13CO2 and 12CO2 gas molecules at 4.3 μm. With the increase of gas pressure from 0.026-0.066 atm(1 atm= 101 325 Pa), the peaks of the absorption spectra of 13CO2 and 12CO2 gas molecular increased with the increase of pressure, the width of the absorption spectra also increased with the increase of pressure. Meanwhile, an infrared gas measuring system was used to measure the CO2 isotope abundance during two hours. The average isotope abundance of CO2 is −9.081‰, and the fluctuation of measured values is between −8.351‰ and −9.736‰, with the maximum deviation of 0.73‰. It can be proved that the system provides reliable guarantee for high performance detection of infrared CO2 gas isotope.
Optical imaging
Research on the bandpass filter used for single-exposure multi-spectral ghost imaging system
Li Meixuan, Zhang Siqi, Li Hong, Li Nan, Ren Yuxuan, Tian Jialong
2020, 49(9): 20200169.   doi: 10.3788/IRLA20200169
[Abstract](15) [FullText HTML](4) [PDF 1379KB](15)
Different from the traditional point-to-point imaging, multi-spectral ghost imaging retrieve the image information of the target by means of modulation and demodulation. In this paper, a single-exposure multi-spectral ghost imaging system based on a fixed phase modulator was built, and the development of thin-film devices in the system was completed. In the thin film, BK7 glass was chosen as the substrate, niobium oxide (Nb2O5) and silicon dioxide (SiO2) were used as the high and low refractive index materials, respectively. Based on the basic theory of optical thin film, the simulation analysis and the film system design were carried out by the film system design software, through setting up evaluation function for film optimization, the design of 450-700 nm band-pass film filter with an incidence angle of 0°-30° was realized and the research and development of this film was completed on OZZSQ900 box-type vacuum coating machine. Through optimizing deposition rate of SiO2 film, the surface defects and scattering loss of film were reduced. The residual evaporation deposition of film was analyzed, the fitting function between film thickness and residual evaporation deposition by least square method was established, monitoring ways was adjusted, residual evaporation deposition was reduced and the accuracy of film thickness control during preparation process was improved. From the test performed by Agilent Cary5000 spectrophotometer, the transmittance is less than 0.5% in the bands of 350-440 nm and 710-800 nm, and higher than 98% in the range of 450-700 nm at the incident angle of 0°-30°, which meets the requirements of the imaging system. The study has important practical significance and engineering value.
Imaging experiments for weak small target in low-light-level background
Hu Haili, He Lei, Zhang Yong, Yang Zhen, Guo Xinmin, Zhang Jianlong
2020, 49(9): 20190569.   doi: 10.3788/IRLA20190569
[Abstract](20) [FullText HTML](15) [PDF 1517KB](15)
Weak small targets, such as unmanned aerial vehicles, have the characteristic of low flight height, small reflection cross-section and weak thermal information, which are difficult to detect and recognize in low-light-level background by a single imaging method. The visible light, low light night vision, long wave infrared and laser active illuminated imaging experiments were carried out, to study the suitable detection and recognition methods by comparing of weak small target images in different low-light-level background. In the field experiment, the target was a small four rotor UAV with the size of 290 mm×290 mm×196 mm, and the environmental illumination was between 10−2 lx and 10−4 lx. The working distance was from 0.5 km to 2 km. The experimental results show that simple visible light system cannot image under 10−2 lx environment illumination; the recognition distance of low-light night vision and long-wave infrared system is only 0.5 km when the environment illumination is 10−4 lx; the active imaging method combining near infrared (central wavelength 808 nm) laser illumination and low-light night vision can increase the recognition distance of weak small targets; under the same condition, the active illuminated imaging working distance is 3 times of the dynamic imaging.
Research progress of APD three-dimensional imaging lidar
Cao Jie, Hao Qun, Zhang Fanghua, Xu Chenyu, Cheng Yang, Zhang Jiali, Tao Yu, Zhou Dong, Zhang Kaiyu
2020, 49(9): 20190549.   doi: 10.3788/IRLA20190549
[Abstract](30) [FullText HTML](10) [PDF 1500KB](13)
Due to the advantages of rich information, strong anti-interference ability and high resolution, three-dimensional (3D) imaging lidar has been widely used in defense and civil fields, such as geomorphology surveys, autopilot, smart transportation and visual tracking. With the development of avalanche photodiode detector (APD) and the multiplicities of 3D lidar (e.g., MEMS, optical phased array, flash, etc.), the performances of lidar has been greatly improved compared with that of initial 3D systems. According to the new requirements on 3D lidar for the military and civilian fields, novel methods and mechanisms were proposed to improve comprehensive performances of 3D imaging. First of all, the three key technologies of APD-based 3D imaging lidar were analyzed, including the transmitting unit, the receiving unit, and the algorithm unit (data processing unit). Then, 3D imaging lidar was classified and discussed according to the different applications for loading. Among them, 3D imaging lidar based on unmanned vehicle was selected as the typical example for illustrating the application status and the difficulties faced with military and civilian applications. Based on the diversified development of 3D imaging methods, two novel 3D imaging methods (heterogeneous resolution and ghost imaging) suitable for APD devices were discussed. Finally, based on the analysis of the research status of 3D imaging lidar, it is concluded that 3D imaging lidar is developing towards the large field of view, high resolution, high precision, real-time, modularity and intelligence, which paves the way for developing high performances of 3D imaging lidar.
Photoelectric measurement
Dual linear array laser thermography detection of arbitrary direction cracks on cylindrical surface
Zhu Xinhao, Hou Dexin, Ye Shuliang
2020, 49(9): 20200097.   doi: 10.3788/IRLA20200097
[Abstract](47) [FullText HTML](13) [PDF 1809KB](7)
Cylinder ferrite magnetic core is a batch of black cylindrical samples and its crack contrast is low. The crack imaging result of traditional machine vision is not good. Laser infrared thermography detection technology relies on the sample surface temperature distribution to detect the crack defects, which solve the problem of low contrast micro crack detection. When the crack is detected by line laser or point laser, the cracks parallel to the laser scanning direction is hard to detect because of the small heat flow on both sides. Dual linear array laser thermography system with dislocation arrangement creates multi-direction heat flow, which can detect arbitrary direction cracks. In order to verify the feasibility of dual linear array laser to detect arbitrary direction cracks, simulation took the laser scanning process of 0°, 45° and 90° cracks. Linear array laser had great non-uniformity in the power distribution of each spot, so different parameter design had great influence on crack detection. Therefore, the design parameters such as spot radius, spot center distance, linear array laser dislocation distance, linear array laser distance, and motion velocity were optimized to improve the SNR in crack detection. Crack imaging algorithm generated cracks based on temperature spatial gradient. Due to the non-uniformity of the laser spots, the gradient of the crack at different relative positions between two laser beams was different. Algorithm selected the position of the cracks with large relative gradient between two laser beams. Through the fusion of multiple gradient images, crack imaging algorithm achieved arbitrary direction crack detection. The imaging algorithm was designed according to the crack spatial temperature gradient characteristics excited by dual linear array laser. Four cylinder ferrite samples with horizontal, vertical and inclined natural cracks were tested, and the imaging results showed all the cracks clearly and intuitively.
3D trajectory planning for gliding vehicle using linear pseudospectral model predictive control
Sun Jianbo, Pan Xinghua, Yang Liang, Chen Wanchun, Zhao Yushan
2020, 49(9): 20200279.   doi: 10.3788/IRLA20200279
[Abstract](20) [FullText HTML](19) [PDF 1282KB](10)
A new entry guidance law for the high lift to drag ratio gliding vehicle was proposed on the basis of the linear pseudospectral model predictive control method. Adopting this approach, the vehicle can arrive at the end of the entry flight with the specific heading angle. Moreover, all the typical constraints such as terminal state constraints and path constraints can be satisfied as well. Firstly, the agent technology using high dimensional polynomials was applied to generalize the lift to drag ratio, hence the analytical expression of the lift to drag ratio was obtained with respect to the energy and the angle of attack. Therefore the angle of attack was designed online to adjust the lift to drag ratio, which can enhance the trajectory planning capacity. The whole entry flight was divided into two phases noted as the descent phase and the gliding phase respectively. In the descent phase, in order to limit the maximum heating rate, the angle of attack remains the maximum allowance value and the bank angle was set to zero. During the gliding phase, the linear pseudospectral model predictive control method was applied. The reduced order dynamic model was formulated to predict the terminal state deviation, and the reduced order dynamic equation was linearized to obtain the error propagation equation. Due to the complexity of the integral calculation, Gauss pseudospectral method was used to derive the correction of the control variables. Finally, terminal state deviations involving final position and heading angle can be efficiently eliminated by modifying the angle of attack parameters, the bank angle parameters and the energy parameters of two bank reversal points. This method is simple and easy to implement with high accuracy, and it is convenient for on-line calculation. The simulation results also show that the planning requirements can be satisfied well through this method.
Design of information processing system for photoelectric seeker
Chen Xianzhi, Luo Zhenbao, Yang Xu, Chen Tao, Zhao Jingtong
2020, 49(9): 20200312.   doi: 10.3788/IRLA20200312
[Abstract](12) [FullText HTML](2) [PDF 1156KB](9)
The photoelectric seeker is an important part of intelligent ammunition, and information processing is the core key technology of its precision guidance. From the perspective of engineering application, the main tasks and technical requirements of the information processing of the photoelectric seeker were systematically analyzed, and the classic distributed modular information processing design technical schemes were sorted out, and its significant advantages and main disadvantages were summarized. With the changes in the requirements of precision guided weapons in future combat objectives, environments and missions, in order to adapt to the development trend of multi-mode composite, intelligent, miniaturized, lightweight and low-cost photoelectric seekers, better meet the constraints of the missile environment urgent needs, make full use of the innovative results of VLSI and information processing technology, in the overall architecture of the photoelectric seeker system, the design ideas of integrated and miniaturized information processing were put forward, and typical application schemes was got, and the core performance was designed. It has significant advantages in terms of comprehensive cost and power consumption, and has strong versatility, which is conducive to the integration of missile guidance platform architecture, missile serialization and upgrading, and provides a reference for the development of a new generation of advanced photoelectric seeker engineering.
Special issue-Metasurface empowered manipulation of wavefront
Nonlinear optics and quantum optics based on metasurface
Shi Mingqian, Liu Jun, Chen Zhuo, Wang Shuming, Wang Zhenlin, Zhu Shining
2020, 49(9): 20201028.   doi: 10.3788/IRLA20201028
[Abstract](78) [FullText HTML](20) [PDF 2906KB](37)
In recent years, metasurface has received extensive attention in the field of classical light control, and excellent results have been obtained. At the same time, the application of metasurface in nonlinear optics and quantum optics has also attracted more and more interest. The basic principles and applications of nonlinear metasurface and quantum metasurface were introduced, and the related reports in recent years were summarized, including the harmonic generation and enhancement, the relationship between harmonic generation and symmetry, the nonlinear phase control and holography, and the generation, measurement and manipulation of entangled photon based on metasurface. Finally, the potential application of metasurface in these two fields were prospected.
Exceptional points in metasurface
Qi Huixin, Wang Xiaoxiao, Hu Xiaoyong, Gong Qihuang
2020, 49(9): 20201029.   doi: 10.3788/IRLA20201029
[Abstract](42) [FullText HTML](19) [PDF 2111KB](27)
Exceptional points are special points in non-Hermitian systems, and there are many novel physical phenomena in the parameter space near the exceptional points. In recent years, metasurface has been a popular topic in physics. A large number of devices with superior performance have been designed based on metasurface platform. The appearance of the metasurface provides an easy platform for the study of exceptional points. By precisely controlling the structural parameters of the metasurface, it is convenient to study the parameter space of the exceptional points. The research on exceptional points in non-Hermitian metasurface also provides a foundation platform for studying new laws of physics. Firstly, the basic theory of exceptional points and the exceptional point in metasurface was introduced. Secondly, the recent research on the exceptional points in metasurface was introduced. Finally, the current problems needing to be solved were analyzed and the development of the field in the future was prospected.
Large field-of-view and compact full-Stokes polarimetry based on quadratic phase metasurface
Zhang Yaxin, Pu Mingbo, Guo Yinghui, Jin Jinjin, Li Xiong, Ma Xiaoliang, Luo Xiangang
2020, 49(9): 20201030.   doi: 10.3788/IRLA20201030
[Abstract](53) [FullText HTML](23) [PDF 1605KB](31)
Polarization is one of the inherent characteristics of light, but the polarization information of electromagnetic waves is lost by traditional intensity and spectral detection technology. At the same time, not only the devices and technologies based on polarimetry have the problem of limited field of view, but also the measuring systems are complicated. In this paper, a compact large field-of-view polarimeter was designed based on dielectric metasurface, which realized the detection of the angle and polarization state of the incident light. The device was composed of 2×2 quadratic phase metasurfaces, each of which realized the symmetry transformation for a specific polarization, that is, the rotational symmetry of the incident angle was converted into the translational symmetry of focus in the focal plane. The theory of the symmetry transformation of the quadratic phase made it possible to characterize the angle of incidence by measuring the offset of the focus over a wide angle range (−40°—+40°). On this basis, the influence of oblique incidence on the measurement of Stokes parameters was elaborated, and the modified Stokes formula was obtained. The Stokes parameters of the incident light can be calculated by utilizing the intensities of the four focal points and the modified Stokes formula. The measured Stokes parameters agree well with the theoretical values, when the field-of-view is 0°, 20°, and 40°.
Complex amplitude modulation of light fields based on dielectric metasurfaces and its applications
Guo Xuyue, Li Bingjie, Fan Xinhao, Zhong Jinzhan, Liu Sheng, Wei Bingyan, Li Peng, Zhao Jianlin
2020, 49(9): 20201031.   doi: 10.3788/IRLA20201031
[Abstract](60) [FullText HTML](25) [PDF 1445KB](38)
Metasurface is an artificially ultrathin material with two-dimensional nanostructure array, which can achieve flexible modulation on amplitude, phase and polarization of light field in a sub-wavelength scale, providing a new possibility for the miniaturization and integration of modern optical devices. With the development of optical imaging, display and so on, the requirement of miniaturized optical devices with high efficiency in visible light band is becoming conspicuous. In recent years, optical metasurfaces fabricated by dielectric materials with high refractive indices and low losses have been extensively studied, showing application prospects in achromatic metalens, polarization-dependent holographic display, et al. Around the research on the metasurface of dielectric, firstly, the generalized Snell's law and the modulation principle of nanostructures in dielectric metasurface on amplitude, phase and polarization of light field were introduced. Then the research progress of dielectric metasurfaces in holographic display and structural light field generation, based on single- and multi-parameters modulation of light field was reviewed. At last, the possible challenges and prospects of dielectric metasurfaces were discussed.
Design and parametric analysis of the broadband achromatic flat lens
Xiao Xingjian, Zhu Shining, Li Tao
2020, 49(9): 20201032.   doi: 10.3788/IRLA20201032
[Abstract](52) [FullText HTML](9) [PDF 1733KB](27)
The design of large scale, high numerical aperture, and broadband achromatic flat lens is a bottleneck of imaging technology and also a big challenge in metalens researches in recent years. The major reason is that there are some internal constraints between these parameters. In this paper, considering both the group dispersion theory and the phase distribution of the flat lens, the semi-quantitative relationship between these parameters was derived. Then, the achromatic flat lenses (including metalenses and multi-level diffractive lenses) with different parameters were designed by using directly binary search and topology optimization. It was found that under the condition of maintaining an efficiency of 80%, when doubling the size of flat lens (i.e., the diameter), the numerical or achromatic bandwidth was cut in half, and the thickness of lens increased linearly with lens scale. The results definitely show that these two types of flat lenses have the same internal constraint relations in parameters, that is, as that the lens size has negative correlation with the numerical aperture and achromatic bandwidth, while positive correlation with the thickness of the lenses. This result is in coincidence with the theoretical prediction.
Development of metasurfaces for wavefront modulation in terahertz waveband
He Jingwen, Dong Tao, Zhang Yan
2020, 49(9): 20201033.   doi: 10.3788/IRLA20201033
[Abstract](49) [FullText HTML](7) [PDF 6200KB](35)
Metasurface is an ultrathin planar device composed of artificial microstructures, which can be used to manipulate the amplitude, phase, and polarization of electromagnetic (EM) waves. Metasurface has the advantages of small volume, light weight, highly integrated, flexible manipulation of EM waves, so it plays an important role in the field of EM wave spectrum and wavefront modulation. In this paper, the research progresses of metasurface for wavefront modulation in the terahertz (THz) waveband were reviewed. The amplitude and phase modulation mechanisms of three kinds of microstructure units in the metasurface, including the microstructure based on Pancharatnam-Berry (PB) phase, localized surface plasmon resonance (LSPR) and Mie resonance were summarized, and the methods for realizing metasurface with high efficiency were discussed. After that, the pure phase and complex amplitude modulation methods for designing the wavefront modulation metasurface were introduced. Specifically, the typical functions, including single function and multifunction and tunable function, of the wavefront modulation metasurfaces in the THz waveband were reviewed. In the early research, metasurfaces were used to realize beam focusing, beam deflection, holographic imaging, and special beam generation such as vortex beam, Airy beam, and Lorentz beam in the THz region. In order to improve the utilization of a THz component, multifunctional metasurfaces, such as metasurfaces with polarization and wavelength multiplexing were proposed. With the requirement of dynamic control of the THz wavefront, some active metasurfaces were proposed and demonstrated. There were two kinds of active metasurfaces. One of the active metasurfaces was formed by combining the metasurface with semiconductor or phase transition materials, and the other was the all-optical metasurface formed by a silicon wafer with pump beam. The all-optical metasurfaces can be reused without reprocessing. The THz wavefront can be modulated dynamically by adjusting the image of the metasurface projected on the silicon wafer. Thus, the all-optical metasurface had the ability to dynamically control the beam steering and focusing, and it can be applied in THz communication, THz radar and other fields. At the end, the development trend and application prospects of the metasurfaces for wavefront modulation in the THz waveband were discussed.
Multi-dimensional metasurface and its application in information encryption and anti-counterfeiting
Deng Zilan, Tu Qing'An, Li Xiangping
2020, 49(9): 20201034.   doi: 10.3788/IRLA20201034
[Abstract](35) [FullText HTML](17) [PDF 1894KB](30)
Metasurface is an artificial layered material with a subwavelength or wavelength-scale thickness. By adjusting the size, shape, orientation angle, displacement, etc. of the metasurface nanostructures, dimensions of electromagnetic wave including frequency, amplitude, phase, polarization, wavelength, etc. can be flexibly and effectively controlled. Metasurface has various characteristics including the ultra-thin thickness, broadband, low loss, easy processing, flexible design and powerful functionalities. This paper reviewed metasurfaces capable of one-dimensional, two-dimensional, multi-dimensional, and active light field manipulations and their applications in information encryption and anti-counterfeiting. An outlook was given for the future development trend of multi-dimensional metasurfaces. Compared with the traditional information encryption and anti-counterfeiting technology, the metasurface has the superior advantages in sub-wavelength pixels, precise controlling and ultra-secure factor in information encryption and anti-counterfeiting. Its bright future to replace the traditional information encryption and anti-counterfeiting technology was envisioned, and its broad application prospects were underpinned.
Progress of micro-nano fabrication technologies for optical metasurfaces
Hu Yueqiang, Li Xin, Wang Xudong, Lai Jiajie, Duan Huigao
2020, 49(9): 20201035.   doi: 10.3788/IRLA20201035
[Abstract](359) [FullText HTML](9) [PDF 10250KB](66)
The metasurface is composed of carefully arranged sub-wavelength units in a two-dimensional plane, which provides a new paradigm for designing ultra-compact optical elements and shows great potential in miniaturizing optical systems. In less than ten years, metasurfaces have caused extensive concern in multidisciplinary fields due to their advantages of being ultra-light, ultra-thin and capable of manipulating various parameters of light waves to achieve multi-functional integration. However, in the optical band, high-degree-of-freedom, aperiodic, and densely arranged metaunits put forward many extreme parameter requirements for fabrication, such as extremely small size, extremely high precision, high aspect ratio, difficult-to-process materials, cross-scale, etc. This poses a great challenge for metasurfaces from laboratory to practical applications. Here, the principles, characteristics and latest developments for micro-nano fabrication of metasurfaces in recent years were summarized, including small-area direct writing methods, large-area template transfer methods, and some emerging fabrication methods. Finally, the current challenges and future development trends of metasurface fabrication were summarized and prospected.
Advances in the research of multifunctional metasurfaces merging computer-generated holography and nanoprinting
Li Zile, Zhou Zhou, Liang Congling, Zheng Guoxing
2020, 49(9): 20201036.   doi: 10.3788/IRLA20201036
[Abstract](160) [FullText HTML](13) [PDF 2245KB](31)
Computer-generated holography and nanoprinting are two typical applications of optical metasurfaces. Recently, merging holography and nanoprinting into a multifunctional metasurface becomes an emerging research hotspot, which has prospective applications in multi-folded anti-counterfeiting, information decoding and multiplexing, multi-channel image display and VR/AR, etc. In this paper, based on the features of metasurface-based nanoprinting and computer-generated holography, the advances in the research of merging them were classified and characterized in detail. Specifically, the merging methods were discussed in detail which included orthogonal-polarization multiplexing scheme, in-plane arrangement scheme, multilayer-stacking scheme, simultaneous spectrum and phase control scheme, complex amplitude modulation scheme, orientation degeneracy scheme. The future development of multifunctional metasurfaces was prospected.
Nonlinear metasurfaces: harmonic generation and ultrafast control
Zhao Yun, Yang Yuanmu
2020, 49(9): 20201037.   doi: 10.3788/IRLA20201037
[Abstract](42) [FullText HTML](9) [PDF 1975KB](29)
Metasurfaces refer to the optical nanoantenna arrays composed of subwavelength structures. Nanoantennas can have resonances under appropriate excitation conditions, to achieve near-field enhancement, and thus enhancing nonlinear optical effects. Compared with conventional nonlinear optical crystals, metasurfaces are more compact, with the possibility for on-chip integration. Due to the subwavelength light-matter interaction length, for applications such as nonlinear harmonic generation, metasurfaces does not suffer from the limitation of phase-matching. In addition, metasurfaces own the subwavelength spatial resolution. By designing and arranging the meta-atoms, metasurfaces can realize flexible control of the phase, polarization, and amplitude of the harmonic wave. Recent works on nonlinear metasurfaces for applications in optical frequency conversion, nonlinear wavefront control and ultrafast all-optical modulation were reviewed, the challenges and perspectives for the practical application of metasurfaces were presented.
Ultrathin invisibility cloaks based on metasurfaces
Chu Hongchen, Lai Yun
2020, 49(9): 20201038.   doi: 10.3788/IRLA20201038
[Abstract](42) [FullText HTML](12) [PDF 1691KB](30)
The invisibility cloak as a longstanding fantastic dream for humans is now within the realm of possibility, thanks to the development of metamaterials. Transformation-optics-based invisibility cloaks have been proposed and realized in many frequency ranges by utilizing gradient-index metamaterials. However, due to the large size of device and difficulty in fabrication, transformation-optics-based invisibility cloaks are significantly limited in practical applications. Recently, metasurfaces as the 2D counterpart of metamaterials have attracted tremendous interests because of its thin thickness and strong capability in manipulating the electromagnetic waves. Ultrathin invisibility cloaks based on metasurfaces release the demand on bulky sizes and extreme parameters, thus promoting further development of invisibility cloaks. This review overviewed recent progress in ultrathin invisibility cloaks based on metasurfaces, focusing particularly on the working principles, implementation methods, advantages and disadvantages. Finally, some advice was put forward on the trends of this fast-developing research field.
From subwavelength grating to metagrating: principle, design and applications
Chen Rui, Liu Xia, Wang Hong, Shi Weiyi, Liu Weinan, Jiang Shaoji, Dong Jianwen
2020, 49(9): 20201039.   doi: 10.3788/IRLA20201039
[Abstract](48) [FullText HTML](16) [PDF 3195KB](40)
With the development of nanophotonics, optical structures, such as optical microcavity, waveguide structure, photonic crystal, subwavelength gratings and metasurfaces, can realize light transmission and manipulation at nanoscale, which promotes the development of optical integration. Subwavelength grating has been widely studied by scientists because of its simple structure and low cost. It has gradually formed a mature theoretical system of grating analysis model when applied to various optical devices. Combined with the coupling of periodic structure and scattering modulation characteristics of meta-atoms, the metagrating derived from subwavelength gratings can improve the efficiency by using periodic Bragg scattering, thus avoiding the efficiency reduction and energy loss caused by the phase discretization. Scientists have studied and designed metagratings, and more physical phenomena and applications have been explored. In this paper, the basic theory, design and application of subwavelength gratings and metagratings were summarized. Based on the basic principle, the characteristics of subwavelength gratings and metagratings were discussed, the theoretical and unit design methods were also outlined and their applications in biosensing, spectral control of filter and absorption film were introduced. Finally, the future development was prospected.
All-optical image processing technology and applications based on micro-/nano-devices
Fu Weiwei, Huang Kun
2020, 49(9): 20201040.   doi: 10.3788/IRLA20201040
[Abstract](46) [FullText HTML](16) [PDF 2040KB](31)
The rapid development of nanotechnology has promoted the processing and manufacturing of micro-nano structures, scientific research and industrial applications. The investigation on optical properties of micro-nano structures has recently been one of the hotspots in the field of optics, which has driven emerging disciplines such as nanophotonics, surface plasmonic optics, metasurface/metamaterial optics, topological photonics, and non-Hermitian optics. It provides the important technical fundamentals for full control of light with high precision. This article focused on the edge detection in all-optical image processing. The fundamentals, principles, technologies and applications of micro-/nano-scale structures and devices were discussed to realize optical mathematical computing (such as differential, convolution), followed by a detailed prospect about its future applications in ultrafast image processing, high-contrast microscopic imaging, convolutional neural networks and intelligent optics.
Progress of polarization-information detection technology based on manipulations of metasurface
Guo Zhongyi, Kang Qianlong, Peng Zhiyong, Cui Yuemeng, Liu Huasong, Gao Jun, Guo Kai
2020, 49(9): 20201041.   doi: 10.3788/IRLA20201041
[Abstract](200) [FullText HTML](20) [PDF 1952KB](56)
Polarization is an inherent property of light. By deconstructing the relation between the incident and transmitting polarization states, the crucial information about the composition and structure of the interacting materials can be obtained, and thus polarization information shows high research value and application potential. In recent years, research areas, such as polarization imaging and polarization information, are flourishing and attracting wide attention of scholars all over the world. A key of these research fields is the acquisition of polarization information with high efficiency. However, conventional methods for acquisition of polarization information have various shortcomings, restricting the development of polarization information. Metasurface technology provides people with an opportunity to artificially change the phase, amplitude and polarization of light wave, with characteristics of miniaturization and integration. Firstly the polarization-information acquisition and the circular-polarization detector based on Archimedes spiral structure were introduced. Then the progress of polarization-information acquisition based on metasurface in recent years, including metal metasurface polarization detector, all-dielectric metasurface polarization detector, and polarization imagings was summarized. At last, the research status and development trend of the polarization-information acquisition technology based on metasurface were discussed.
Lasers & Laser optics
Influence of phase additive effect on beam smoothing character of continuous phase plate
Yang Chunlin
2020, 49(9): 20190515.   doi: 10.3788/IRLA20190515
[Abstract](8) [FullText HTML](3) [PDF 1624KB](6)
During the operational process of high power laser system, the uniformity of focal spot will impact the experiment and application seriously. To improve the focal spot quality, a continuous phase plate (CPP) should be used in the light path for far field beam smoothing. As a phase element CPP has different functions, such as decoherece and beam shaping. In this paper the smoothing performance of CPP was concerned. Good performance of beam smoothing depended on a reasonable surface figure distribution. According to the random characteristic of phase plate surface, the statistical method was employed to study the beam smoothing mechanism. According to the relationship between the probability density and far field histogram of the surface of CPP, the expression of the superposition intensity envelope of distorted beam and CPP surface figure was deduced. The formula proved that the function of a CPP for focal spot was just a convolution filtering. So the mathematical explanation on the beam smoothing mechanism was achieved. Furthermore, using this analysis model the reason that the CPP with short correlation length will have the capability of better beam smoothing was explained theoretically. Numerical simulations were done to show the beam smoothing performance of CPP. The far field histograms with different distorted beams are calculated and compared. The results show that after the phase additive of the distorted beam and CPP a new wavefront was generated. If the law of large numbers is satisfied, when the correlation length and the gradient of the wavefront is small, the light focus spot distribution is smooth and uniform. The statistical geometrical optical method used in this paper can reduce the analysis difficulty on the phase additive effectively.
Laser polarization characteristics of visible light band in different humidity environments
Zhan Juntong, Zhang Su, Fu Qiang, Duan Jin, Li Yingchao, Jiang Huilin
2020, 49(9): 20200057.   doi: 10.3788/IRLA20200057
[Abstract](833) [FullText HTML](723) [PDF 13320KB](19)
Haze weather interferes with the visible light imaging effect, and the polarization characteristic of visible light can effectively improve the detection efficiency. Haze environment is affected by aerosol particle humidity, which is an important physical parameter of haze environment. In order to obtain the polarization characteristics of visible light in haze environment, the influence of humidity in haze environment on polarization characteristics was analyzed. Based on the single particle scattering characteristics of non-polarized light aerosol, the polarization transmission model was established by improved Monte Carlo method, research on transmission characteristics of polarized light in visible bands under different humidity and water mist was conducted, the influence of humidity change in water mist environment on polarization characteristics of polarized light in different visible bands was analyzed, and a near-real water mist environment was built. The polarization model was verified by laboratory experiments, the change of polarization degree and polarization state of linear polarized light on 450, 532 and 671 nm was compared and analyzed under different humidity conditions, the confidence of simulation model was more than 60%. The results show that the polarization degree of polarized light decreases with the increase of humidity of water-fog environment. With the increase of the wavelength, the polarization tends to be flat, while the exit polarization degree increases with the increase of wavelength. The humidity values of the descending point of polarization degree are 50%, 70% and 90% when the laser wavelengths are 450, 532, 671 nm, respectively. For water mist, which is easily affected by humidity, polarized light with longer wave length should be selected as far as possible for transmission detection in visible band. Because humidity has a greater influence on shorter wavelengths than longer wavelengths, circularly polarized light with longer wavelengths has the best polarization retention characteristics in environments with higher humidity. In the environment with high humidity, polarized light imaging with long wavelength should be selected as far as possible to achieve better imaging effect.
Scattering properties of non-spherical cluster core-shell structure particle laser
Ren Shenhe, Gao Ming, Wang Mingjun, Bao Xiujuan, Li Yan
2020, 49(9): 20190545.   doi: 10.3788/IRLA20190545
[Abstract](13) [FullText HTML](10) [PDF 2230KB](7)
On the basis of heterogeneous nucleation theory of ice crystal particles, three types of ice crystal particle models were established with nucleation-shell structures of ellipsoid, hexagonal flat plate and hexagonal prism. The extinction, absorption and scattering efficiency of these three special cluster-shaped core-shell structures were numerically calculated by discrete dipole approximation (DDA) method. Under the same incident wavelength, the effect of effective size on the extinction efficiency, absorption efficiency and scattering efficiency of core-shell ice crystal particles, the influence of the intermediate uniform mixing layer on the scattering intensity of core-shell ice crystal particles, and the variation of Mueller matrix elements with the scattering angle were calculated. The numerical results show that the extinction coefficient, absorption coefficient and scattering coefficient of ice crystallites with three clusters of ellipsoidal, hexagonal and hexagonal prisms show different trends with the increase of effective size. Under the condition of equal size, the scattering intensity with the change of the scattering angle and particle shape have close relations, and compared with the ellipsoid and hexagonal flat two cluster core-shell structure of ice crystal particles, core-shell structure of ice crystal particles hexagonal prisms forward scattering intensity, the largest scattering intensity curve along with the change of the scattering angle oscillation is more obvious. According to the distribution of the Mueller matrix elements with the scattering angle, it can be seen that the scattering direction of the hexagonal prism cluster ice crystal structure is the most obvious, and the forward scattering intensity is the largest. The Mueller matrix elements of the hexagonal plate and hexagonal prism cluster ice crystal structure are relatively spherical and the deviation of the ellipsoid in the backscattered field area is more obvious. The research results of the thesis provide support for further analysis of the scattering characteristics of complex ice crystal particles, and the research and analysis of the scattering characteristics of various complex geometric clusters of ice crystal particles in high-altitude clouds.
Laser-induced transformation of carbon nanotubes into graphene nanoribbons and their conductive properties
Liu Zhi, Chen Jimin, Li Dongfang, Zhang Chenyu
2020, 49(9): 20200298.   doi: 10.3788/IRLA20200298
[Abstract](25) [FullText HTML](13) [PDF 1023KB](15)
GNRs can be readily produced by unzipping the nanotubes because CNT structure can be analogically considered as graphene sheets rolled up. This is a special 2D graphitic structure performing the exceptional properties. Due to the unique structure and the outstanding properties, GNRs have been used in a vast range of applications, including transistors, optical and microwave communication devices, biosensors, chemical sensors, electronic memory and processing devices, nano electromechanical systems, and composites. The morphology of the fiilms was observed by scanning electron microscopy (SEM), and the properties of graphene were characterized by Raman spectroscopy. The conductivity of the fiilms was measured by a semiconductor parameter measurement system. Raman spectroscopy showed that the Raman characteristics of graphene characterized by optimized process were enhanced. Laser energy and irradiation time were two important parameters for the preparation of graphene from carbon nanotubes. In this study, to open carbon nanotubes by laser, graphene nanoribbons were produced by excimer laser irradiation of carbon nanotubes thin films. The experimental results show that, with the laser energy 150 mJ, the carbon nanotubes are not opened while the connection is observed. With the energy 450 mJ, the carbon nanotubes can be effectively destroyed, and graphene strips can be partially opened to form. At this time, the conductivity of the fiilm reaches the maximum value. Due to the thermal accumulation effect, a large number of porous structures appear on the wall of carbon nanotubes.
Longitudinal forced convection heat transfer for high power slab laser media
He Jianguo, Li Ming, Mo Zeqiang, Wang Jinduo, Yu Jin, Dai Shoujun, Chen Yanzhong, Ge Wenqi, Liu Yang, Fan Lianwen
2020, 49(9): 20200556.   doi: 10.3788/IRLA20200556
[Abstract](6247) [FullText HTML](1408) [PDF 9424KB](797)
Thermal problem becomes more prominent in the highly-pumped laser gain mediums, for which, the forced convective heat transfer with the advantages of reliability and durability is widely used. However, a flow direction induced temperature gradient always appears within the laser operating substance during the convective heat transfer. Subsequently, it is significantly responsible for the detrimental thermal stress which mainly cause the wave front distortion. Herein, considering the idea of temperature matching between flow field and the operating substance, a cooling configuration for double face pumped slab crystal based on longitudinal forced convective heat transfer was presented, which showed a more efficient cooling and achieved a most homogeneous temperature distribution within the crystal. The influences of flow rate, state of flow field and surface roughness were systematically studied that a fully developed flow state, higher flow rate and rougher surface lead to an improvement in cooling capability. In the simulation with 30 L/min flow rate, the calculated convective heat transfer coefficient was as high as 104 W·m2·K−1, and even higher when a more coarse surface was implemented. Furthermore, a module based on the configuration was fabricated and the experimental results agree well with the simulation, which shows a good temperature distribution and very weak thermal lensing is achieved.
Band gap and local electric field characteristics of surface waves in left-handed and right-handed materials of photonic crystal
Xu Jiangyong, Zhou Bo, Su An, Meng Chengju, Gao Yingjun
2020, 49(9): 20200052.   doi: 10.3788/IRLA20200052
[Abstract](19) [FullText HTML](14) [PDF 1376KB](5)
The energy band structure and the surface wave local electric field distribution of the left-handed and right-handed photonic crystals materials, were studied based on parameter matching by using the transmission matrix theory of plane wave and Bloch theorem in order to study and design novel optical waveguide and optical sensor. The results show that there are semi closed and closed band gap structures in the energy band of the left-handed and right-handed materials with zero mean refractive index, and the energy level curve in the transmission band attenuates from high frequency to low frequency with oscillation. After the surface coating medium is added, the discrete energy level of forward and reverse waves appear in the partially semi-closed and closed band gap of the photonic crystal, the discrete energy level moves to lower wave vector with the increase of the coating thickness, and the discrete energy level in the semi-closed band gap splits when the coating thickness is at a certain value. In the band gap, the maximum value of the local electric field of the forward surface wave and the highest light intensity are near the junction of the coating and the surface of the photonic crystal, and decay with the coating thickness increasing or away from the junction. The response sensitivity of the maximum value of the local electric field corresponding to the closed band gap to the coating thickness is weaker than that of the semi closed band gap. In the band gap, the local electric field, the maximum value of the local electric field of the reverse surface wave and the highest light intensity are in the the photonic crystal, and increase with the coating thickness. The local restriction of the closed band gap on the reverse surface wave, the coupling effect of the surface wave and the incident light, and the response sensitivity of the local electric field to the coating thickness are stronger than those of the semi-closed band gap.
Tunable light absorption in Ru atomic vapor driven by three coherent fields
Li Dongkang, Gao Liyuan, Wang Tao, Tian Xingxia, Fu Changbao
2020, 49(9): 20190528.   doi: 10.3788/IRLA20190528
[Abstract](6) [FullText HTML](1) [PDF 1145KB](6)
In recent years, based on the intense interaction between coherent light and matter, the controllable quantum interference phenomena, such as coherent population trapping, electromagnetically induced transparency and electromagnetically induced absorption, optical hole-burning, have attracted a comprehensive concern. For exploring the controllable characteristics of light absorption involving the coherent hole-burning, a four-level N-type atomic system was proposed, which was driven by a strong coherent light field and two coupling fields with the Doppler broadening thermal rubidium vapor. Via introducing the coupling fields and then adjusting the intensity of the coupling field in such an atomic system, some interesting quantum optical phenomena can be observed. Based on the design of this atomic model, the expression of absorption spectrum of the weak probe light fields was derived via the Laplace transform with the system Hamiltonian equation and density matrices. In the design of optical scheme, the saturated light field was inputted with the same or opposite propagating direction as that of the two coupling light fields, which was opposite the weak probe light field. In such a scheme, six coherent optical hole-burnings and one window based on electromagnetically induced transparency may be realized. With the adjustment of the relevant parameters in terms of the intensities and frequencies of the light fields, the enhancement or weakening of the light absorption can be realized in the absorption spectrum, including the change of the position and number of the optical hole-burning. By the transition of atoms excited by the fields, both electromagnetic induced transparency and electromagnetic induced absorption appeared at the same time. Through the adjustment of light field and the comparison of simulation results, the generation and conversion of the two quantum coherence effects were deeply studied. It is concluded that these results may have a good theoretical guidance for the popular optical quantum storage.