Research on the beam quality of diode lasers based on Wigner distribution function

Laser beam quality is an important parameter to evaluate the spatial characteristics of laser field. Based on the Wigner distribution function, the beam quality characteristics of one-dimensional field are analyzed and the beam quality factor is divided into intensity term, wavefront term and coherence term. The model shows that the incoherence in laser field affects the coherence term of the beam quality through the incoherence coefficient K(x(1), y(1); x(2), y(2)), and then affects the beam quality of the whole field. The beam quality evolution trend of diode lasers with mode hopping or multi-mode in longitudinal mode is analyzed by simulation. It is shown that when the order of longitudinal modes in the laser increases, the influence on the beam quality is related to the laser field distribution, the depravation of beam quality is proportionally related with the transverse mode component of diode lasers.