Study On Measurement Technology Of Laser Scattering Rate

In some high precision optical testing,such as detection of ultra smooth high reflection mirror,optical surface scattering,the existence of a large number of scattering particles in the atmosphere environment,the particle scattering light will produce certain interference on the measurement results.If the detection signal is very weak,such effects can not be ignored.At the present stage,the method of environmental assessment is mainly to measure the concentration of particles in the environment,but these methods are either complicated or difficult to be popularized.In order to solve the above problems,this paper designs a kind of atmospheric scattering rate measuring device to evaluate the environment.The scattering rate measurement system is based on a stable power laser,The scattered light is collected in the integrating sphere When the beam passes through the integrating sphere which the particles in the environment can enter,and the scattered light is measured by a photo multiplier tube.The system uses the lock-in amplifier to process the signal,which can effectively remove the background noise.The measurement system mainly consists of light source,light path,detection and data processing.The semiconductor laser is used as the core part of the light source,and the driving circuit of the semiconductor laser is designed to realize the stable output of laser power and electrical modulation;The main function of the optical path is the turning point of the beam,the attenuation and the elimination of stray light;In the detection part,the scattered light is collected,and the photoelectric signal is converted and amplified by the photo multiplier.The data processing part uses the lock-in amplifier to realize the correlation detection technology,and effectively improves the signal to noise ratio(SNR);Using SCM as the control chip digital analog conversion and display circuit and other auxiliary circuit is designed.Based on the above scheme,built the scattering rate measurement system,and the scattering rate is measured in the laboratory environment.The experimental results show that the measurement system can meet the design requirements of 1?100ppm.The accurate measurement of laser scattering rate is realized,showing high precision,convenient,rapid testing,wide application.