基于原子鉴频的大气瑞利-布里渊散射光谱探测研究

Rayleigh-Brillouin scattering is an important phenomenon in the atmosphere. It is of great scientific significance and application value to conduct the theoretical modeling and experimental measurements. This project proposed a lidar detection method based on atomic frequency discrimination and stabilization to experimentally explore the Rayleigh-Brillouin scattering spectrum at different altitudes of the real atmosphere. Currently the method employed a Fabry-Perot Interferometer (FPI) as the frequency discriminator, which was hard to obtain a high resolution profile of backscattering for the contradiction between the free spectral range and finesse. Different from the existing method, our method proposed in the project adopted the technologies of atomic frequency discrimination spectrally cascaded with FPI, atomic frequency stabilization and echo reception method in lidar detection, which led to high performance in the resolution, stability and sensitivity. All the technologies mentioned above will help to improve the measurement accuracy. Implementation of the proposed method will not only validate and evaluate the theoretical model, but also be applied to Doppler Lidar for the improvement of temperature and wind detection accuracy.

大气对光的瑞利-布里渊散射（Cabannes散射）是一种重要的光散射现象，对其开展理论建模和实验测量研究具有重要的科学意义和应用价值。本项目拟采用基于原子鉴频和稳频的激光雷达探测方法，对各高度层段的真实大气瑞利-布里渊散射光谱线形开展实验测量探究。目前国际上已有的FPI（Fabry-Perot干涉仪）探测方法存在光谱自由程与精细度相互制约的矛盾，难以获得高分辨率的回波光谱线形。与其相比，本项目研究采用了原子鉴频与FPI光谱级联、原子稳频以及激光雷达回波接收的探测方法，具有测量光谱分辨率高、发射激光频率稳定和接收灵敏度高等优势，有利于提高实验测量精度。本项目研究方法的实施，可对相应理论模型进行验证与评价，并可用于现有基于多普勒原理的激光雷达探测中，以提高其温度和风场探测精度。

原子鉴频大气瑞利-布里渊散射光谱探测方法具有高光谱分辨率和高稳定性的特点。本项目开展了基于钠原子鉴频的大气散射光谱探测方法研究。研究过程中采用中心峰透射的单峰原子鉴频器对大气散射光谱信号进行接收，通过调谐并锁定发射激光在不同频率点上，获得大气散射光谱线型。完成了如下3项主要研究内容：（1）分析不同大气高度和气溶胶含量下的瑞利-布里渊散射光谱线型；（2）单峰透射谱型原子鉴频器的设计和研制以及FPI光谱匹配；（3）大气瑞利-布里渊散射光谱探测实验验证。通过项目研究，促进了大气散射光谱探测方法的发展，为研究大气散射光谱模型奠定实验基础。本项目实验观测获得了不同大气高度层段的散射光谱回波信号，为风场探测激光雷达数据反演修正提供校正。