扫描近场圆偏振光学显微镜

Scanning near-field circular polarization optical microscope

  • 摘要: 提出一种利用镀有金属薄膜的V形无孔光学探针构建的扫描近场光学显微镜,将圆偏振光注入镀有金属薄膜的V形槽内在针尖处形成近场照射光源,并利用探针收集样品表面近场光信号。理论分析表明:探针收集的近场和远场反射光之间存在一定的相位差,该相位差与探针机械结构、探针与样品的距离有关,可通过探针与样品之间的距离加以控制,因此利用偏振性器件可有效抑制远场光强。实验中,探针与样品之间的距离通过范德华力回馈控制,探针操作在接触模式,实验结果显示所测近场与远场光相位相差57,近场光学图像横向分辨率优于12 nm。

     

    Abstract: A scanning near-field optical microscope (SNOM) based on an apertureless optical probe was presented. The probe had a V shape hollow on its top and coated with metal film. Illumination near-field light (NFL) will emit from the apex of probe when far-field light (FFL) is focused on the hollow. There is a phase difference between collected NFL and FFL, which relates to the distance between probe and sample. The collected FFL can be eliminated using a Glan-Taylor analyzer according to the phase difference. The experimental results show the phase difference of this system is 57. The spatial resolution of SNCOM is less than 12 nm.

     

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