Study on the laser beam transformation and its measurement in laser processing

Abstract

The shape and energy distribution of laser beam directly define its applications in laser processing. In order to cater for different laser processing requirements, the input beam always needs to be transformed. The transformation between the solid beam and ring beam can be realized by the axicon-based optical devices. A beam transformation optical system, which uses a pair of positive axicon and negative axicon is designed and analyzed. The novelty of the optical system is not only that they can focus the laser beam on a ring pattern or solid beam pattern, but also that they can change the diameter of patter easily by adjusting the separation of the two conical lenses. The optical system is analyzed based on the geometry optical theory. By adjusting the separation of the convergent conical lens and the divergent conical lens, different shapes and the energy distributions are gained. At last, a measurement method of the beam profile is introduced which based on charge coupled device (CCD) The results show that the axicon-based beam transformations raise the effectiveness of laser and have a wide application prospect in laser processing field.