Design of aspherical laser cavities

Abstract

Most previous attempts reported in the literature to reshape the Gaussian energy density profile of the fundamental mode of a laser into a more uniform irradiance beam have been accomplished by using lenses, mirrors, or gratings external to the laser cavities.1,2 The idea of deforming one mirror of a laser resonator by introducing a second discontinuity of the mirror surface to reduce diffraction effects has been investigated.3 The geometrical optics properties of aspherical optical resonators with nonuniform magnification have also been investigated.4 In the present work, a new method to reshape the energy profile of laser beams is explored. Kirchhoff diffraction theory has been applied to the design of confocal aspherical laser cavities, which represents an extension of the Fox-Li laser cavity theory. The added degrees of freedom of aspherical cavity mirrors offer attractive options for obtaining more uniform irradiance laser beams, taking into account diffraction effects.