Laser beam quality factor M2 and its measurement

摘要

The factor M$+2$/ is a new parameter to describe the laser beam quality, it can characterize the propagation of the fundamental and higher-order mode beam quantitatively. An automatic measurement system has been developed which is capable of measuring the laser beam quality factor M$+2$/. In the paper, the concept and the measurements of the factor M$+2$/ are mentioned, the measurement results and tolerance limits are given.