Characterization of beam quality of 10-kW class laser

Abstract

The laboratory model of 10-kW class laser effector was designed and assembled. The special laboratory setup for characterization of its parameters and research on interaction with materials was developed. As a result of dynamic thermaloptic phenomena inside laser source and measurement setup the observed laser beam distributions in far field present features of 4D spatial-temporal, non-stationary stochastic process, thus averaging in given plane over long exposures times was not justified. Measurement of laser beam parameters directly in far field and Wavefront Sensing Measurement by Shack-Hartmann method were applied in experiment. To analyze the experimental data of distorted wavefront measurements Wigner Transform method was applied. Beam quality and brightness determined via Wigner approach was changed in the same way as the direct measurements of beam parameters in far field. The deterministic aberration as a result of dynamic thermal-optic effects depending on averaged laser power was found, which can explain non-Gaussian profiles in the vicinity of focal plane.