Application of integrating sphere in Rayleigh wind lidar

The intensity distribution of the illumination on the interferometer affects obviously on its transmission curves and then influences on the inversion of wind velocity. However, the incident laser into the integrating sphere is diffuse in the cavity wall and the output laser flare becomes uniform, thereby making the transmittance curve more precise. Meanwhile the pulse width of the output laser is increased in the time domain and this will improve the signal to noise ratio of the detection, thereby making the transmittance curve more stable. For the same reason, the process of the frequency locking is more precise. These two properties of integrating sphere, which are used for 355 nm Rayleigh wind lidar system will greatly enhance the stability of detection and the signal to noise ratio. The transmission curves will be scanned through the integrating sphere. The results show an accuracy of 0.061 m/s for the maximum error and 0.054 m/s for the average wind velocity of less than 100 m/s.