Measurement of the absorption spectrum of methane by using a tunable Er∶YAG single frequency laser

It is an important method to measure the concentration of methane(CH4)by using 1.6μm laser differential absorption.By analyzing and calculating the absorption spectrum of CH4,based on a tunable Er∶YAG single frequency laser,the absorption of CH4 towards 1.645μm laser is measured experimentally.The results are useful for selecting the LIDAR's source for measuring the concentration of CH4.