Laser thermal lens measurement based on Michelson interferometer

In this paper, a laser thermal lens measuring device which is based on equal inclination interference fringes produced by Michelson interferometer is realized. In this experiment, the thermal effect of low power laser can be observed as the ink sample after dilution has good endothermic properties. The experimental results show that the number of bright and dark rings is 6 in the absence of medium. With the increase of the concentration of the ink sample, the number of dark rings is also changing, and the spacing is relatively larger. Therefore, the thermal lens effect of laser can be observed by adjusting device. The focal length of the thermal lens is also calculated. The device has high application value in the study of laser thermal lens effect and medium absorption.