Design and characterization of beam shapers for end-pumped lasers

Abstract

To homogenize inversion profiles and mitigate thermo-optic effects in high-power, end-pumped lasers the optimal spatial profile of pump beam should be close to ‘top-hat’ one, whereas typical pumping beams have Gaussian-like profiles. The aim of work was to examine feasibility of laser beam transformation with the use of a beam shaper consisted of a pair of aspheric refractive elements. Two beam shapers (with magnification m = 0.4, 0.8 respectively) for transformation of Gaussian profile to Super-Gaussian were designed and fabricated applying Magneto-Rheological Finishing technology. Both elements were experimentally verified for diffraction limited and partially coherent laser beams. The analytical model based on Fourier transform plane wave decomposition was applied for verification of experiments and to determine the performance of fabricated elements.