Optical design of laser beam shaping systems

Abstract

An overview of the history and current practices of laser beam shaping is presented. When diffraction effects are not important, geometrical methods for laser beam shaping (ray tracing, conservation of energy within a bundle of rays, and the constant optical path length condition) can be used to determine system configurations, including aspheric elements and spherical-surface GRIN lenses, which are required to change the intensity profile into a more useful form. Geometrical optics-based design methods are presented for shaping both rotationally and rectangular symmetric laser beam profiles. Applications of these techniques include design of a two-plano-aspheric lens system for shaping a rotationally symmetric Gaussian beam, a two-mirror system with no central obscuration for shaping an elliptical Gaussian input beam, and a three-element GRIN system for shaping a rotationally symmetric Gaussian beam.

Laser material processing

“…Beam shaping plays an important role in determining the quality of hardening, welding and laser microprocessing. 12 12,13 The beam shaping techniques may broadly be classified into three categories 13. The first, and most simple, class of beam shaping is aperturing, which is achieved by using an aperture to allow some portion of the beam power to pass through while the rest of the beam is either reflected or absorbed.…”