Effects of small misalignments on the intensity and Strehl ratio for a laser beam focused by an off-axis parabola

L. Labate, P. Ferrara, L. Fulgentini, L.A. Gizzi

Applied Optics 55, 6506-6515 (2016)

Abstract

A general procedure is described to calculate the intensity and Strehl ratio, at a generic plane in the focal region, of a beam focused by an off-axis parabolic mirror in the presence of small misalignments. The general theoretical framework is first developed, which allows a full vector diffraction treatment in the case of general misalignments. Then, a parametric numerical study is reported, aimed at highlighting the tolerances of both the intensity and Strehl ratio for small misalignments, for different focusing and off-axis parabola parameters. A set of experimental measurements aimed at validating the theoretical model is also discussed.