Research On Laser Interferometry Method Of Absorption Coefficient Of Atmospheric Suspended Particles

Absorption coefficient of atmospheric particles not only can be used to measurethe particles’ strength of affecting the spread of light in the atmosphere, but also beused to estimate the radiation intensity of the particles. Carrying out a study ofaccurate measurement of suspended particulate absorption coefficient is very urgentand necessary.This paper begins studying the basic mechanism of photothermal interference ofmeasuring the particles’ absorption coefficient from the photothermal theory, andpresents a low-cost and high-precision measuring method of measuring the absorptioncoefficient of atmospheric particles. The method replaced the corner reflector andpiezoelectric ceramic used in traditional Jamin interferometer by beam positionadjustment board, and that reduces system cost and improves the control precision. Byanalyzing the sensitivity of the measurement, this paper presents a method to improvethe system sensitivity. At the end of this paper, it analyzes the several uncertaintiesmay appeared in the measurement system and combine the uncertainties.This paper’s research and analysis show that the proposed method can achievehigh-precision and low-cost measuring the absorption coefficient of atmosphericparticles.The minimum detectable absorption coefficient under common measuringenvironment can reach15.94Mm-1.The N-Times method can significantly improvesthe system’s sensitivity to the original1/N under the same measuring environment andthe conditions’ permission. The combined uncertainty of the measurement system isbetter than0.7%.