In order to achieve high signal-to-noise ratio by using small laser energy and telescope aperture, we present a polarization filter in high-spectral-resolution lidar (HSRL) for the measurement of atmospheric temperature. Compared with the filter method in a traditional HSRL in which the intensity of the return signal is split into the different transmission channel of a discriminator, the advantage of this filter system is that the intensity of the return signal is fully utilized for each discriminator channel, and the return signal changes the polarization state of the light without loss of intensity when it is incident on the two Rayleigh channels. In addition, the daytime detection capability of HSRL is improved by using a polarization optical scheme to suppress the solar background light. The advantages of the polarization filter are proven by the theoretical calculations using the Stokes vector and a Mueller matrix. In detection experiments of atmospheric temperature, the detection height is 4 km at night and 2.5 km during the day by using the pulsed energy of 50 mJ and telescope diameter of 250 mm. The results are in good agreement with the data detected by radiosonde.

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In order to achieve a high signal-to-noise ratio by using small laser energy and telescope aperture, we present a detection method based on Rayleigh-Brillouin scattering (RBS) for the measurement of atmospheric temperature without response functions and calibration procedures by using high spectral resolution lidar (HSRL). Different from the traditional HSRL, a Fabry-Pérot interferometer (FPI) with a continuous tunable cavity and polarization optical scheme are employed in a high spectral resolution filter. In order to continuously change the resonant frequency of the FPI, an electro-optical crystal of potassium dideuterium phosphate (DKDP) with two ring electrodes is used as a continuous tunable cavity in the FPI. At each scanned frequency point corresponded with the resonant frequency of the FPI, the received signals of four discrete points on RBS are obtained. Atmospheric temperature is inverted by using a RBS model. The polarization optical scheme is used to suppress the solar background light, and improve the utilization of return signals. In detection experiment of atmospheric temperature, the detection height is 2 km at night and 1.5 km during the day by using a pulsed energy of 30 mJ and telescope diameter of 250 mm. The results are in good agreement with the data detected by radiosonde.