Simulation and experiment studies of aberration effects on the measurement of laser beam quality factor (M2)

- We study the wavefront and intensity aberration effect on beam quality factor M2.
- We give the tolerance range of the wavefront and intensity aberrations in a high-power fiber laser system for controlling the influence on M2.
- The influence of different aberrations on M2 of a high-power fiber laser is simulated.
- The influence of wavefront aberration caused by thermal effect on M2 is simulated and measured.

In the measurement system of beam quality factor, M2, wave-front and intensity aberrations caused by optical elements, thermal effects, residual pump light, etc., influence the measurement results. The influence was analyzed using the angular spectrum and the finite element methods. Simulation of the impact of different aberrations, thermal effects and residual pump light on the measurement of the M2 is provided. The M2 of a high-power fiber laser is measured by a beam quality analyzer when the laser transmits through a high absorption red glass with different output power. The results from the experiment and the simulation have good consistency. The simulation and experiment results can be applied for the designs of high-power laser, laser beam quality measurement, and laser-launching systems.