Study On Optical Scattering Characteristics Of Surface Microstructure For Optical Elements

With the rapid development of the laser technology,more and more attention has been paid to the light scattering loss caused by the surface micro structure of optical elements.The influence of light scattering caused by the roughness of the the optical element surface will be increased exponentially with the increase of irradiation on the elements,which lead to strong scattering loss and beam modulation,and can seriously affect the light energy concentration degree.The method of BRDF(Bidirectional Reflectance Distribution Function)based on light scattering is one kind of higher speed and precise resolution for microstructure nondestructive detection techniques.The scattering characteristics can be obtained and analyzed by the scattering modulation of incident light through scattered light signal being collected.So exploring the law of the microstructure and the light scattering properties is laid a foundation for the more comprehensive system of microstructure scattering.First of all,the methods of the common geometric distribution and the statistical characterization of the surface microstructure are introduced.The approximate methods of the rough surface are discussed,and then its existence and application conditions are analyzed.Secondly,the basic principles of BRDF and the polarization scattering distribution function are discussed.On this basis,the numerical models of scattering distribution of optical elements are established.Then,the influences of different factors,such as incident angle,surface roughness,incident wavelength and correlation length are simulated and analyzed for non-polarization scattering properties by using Matlab software simulation.At the same time,the influences of incident angle and azimuth angle on the polarization scattering characteristics are strudied,meanwhile the influence of the incident angle on P-polarized scattering is analyzed emphatically.Lastly,the BRDF experiment measurement system is built.The K9 glasses are measured,meanwhile the date was contrasted with the theoretical value.The PSD(Power Spectral Density)is inversed by BRDF experiment data,and compared with the data obtained by CCI 2000.It is found that are in good agreement with.The experiment results verify the correctness of simulation experiment and effectiveness of numerical model.These results provide references for the research on the scattering characteristic of optical elements detection theory.