The Study Of Rayleigh Brillouin Scattering Spectra In Several Characteristic Gases

With the developments of atmospheric detection techniques, Rayleigh-Brillouin scattering of laser detection technology as a new detection technology, will bea new direction of development of laser detection technology in the future. In thispaper,a series of basic theory and experiment on Rayleigh-Brillouin Scattering has beendone, that provides theoretical and experimental basis for the atmospheric Rayleigh-Brillouin scattering of laser radar.Atmospheric Rayleigh-Brillouin frequency shift are related with temperature，pressure, air density, and other related parameters. One of those parameters can beinverted by the Rayleigh-Brillouin signal comparison with the Rayleigh-Brillouinmodel. Therefore, Rayleigh-Brillouin scattering model is very important for Brillouinlaser detection system. Firstly, spectrum spectral line broadening is introduced andPrimitive kinetic Wang Chang-Uhlenbeck (WCU) equation and collision operatorequation has been introduced, thus gain the S6collision model. Using S6modelsimulate Rayleigh-Brillouin scattering spectrum，analysis of the spectrum shapevariation, Find out that with the increase of gas pressure and temperature, RayleighBrillouin scattering was stronger, the simulation of different gases show that the changein its molecular weight has little effect, on the simulation of different wavelengths ofincident light, the incident light wavelength the greater the Rayleigh Brillouin scatteringis stronger, the theoretical simulation of the above provide a theoretical basis for theexperiment.Through the above work, the experiments of this paper, Using single-mode laserstudy effect of pressure for the scattering signal. Scattered light was collected at anominal angle of90°to the incident light propagation direction using532nmcontinuous laser for the light source. Indeed receive scattering signal throughcomparison F-P eigen signal. On the side, scattered light of different pressure wascollected at a backward angle of180°to the incident light propagation direction using532nm pulse laser for the light source. The variation of pressure was a factor ofaffecting scattering signal through comparison experiment. Scattering signal isincreased pressure to strengthen and the scattering spectrum is widened, because of pressure strengthen. Rayleigh scattering signal enhancement is advantageous for the Brillouinsignal detection.