The Measurement Of The Laser Light Beam Divergence Angle

this paper introduced two methods of measuring the angle of divergence of laser beam on the base of Gauss light beam theory of semiconductor laser according to different magnitude of divergence. when the divergence is big ,in this paper we use Focus Facula Measurement method ,which means we can measure the facula size real-time and swiftly. Considering the lab condition,we can also use Double-Shearing Interference Testing when the divergence is approaching the diffraction limit.Based on Jamin's lateral shear interferometer, use four pieces of wedge plane plate divided the fringe pattern into two parts, we can figure out the height and symbol of the wavefront by the differences of the two parts' fringe space, then the beam angle of divergence can be calculated.