Method and device for obtaining focal length and spherical aberration of laser crystal thermal lens

Abstract

The invention discloses a method and a device for obtaining the focal length and spherical aberration of a laser crystal thermal lens. The method comprises the following steps: determining an inversion model between wavefront information and the focal length and spherical aberration of the laser crystal thermal lens; determining or measuring to obtain an inversion parameter set; and obtaining thefocal length and spherical aberration of the laser crystal thermal lens based on inversion parameters in the inversion parameter set and the inversion model between wavefront information and the focallength and spherical aberration of the laser crystal thermal lens. The method and the device have the beneficial effects that the practical situation of common influence of wavefront information on the focal length and spherical aberration of the thermal lens is taken into account, more complete inversion model between the wavefront information and the focal length and spherical aberration of thelaser crystal thermal lens is obtained, and the incompleteness on light beam quality influence factor analysis is avoided, so that the analysis of the distribution conditions of thermal lens effect and spherical aberration effect generated by a gain medium under a working condition is more facilitated, and useful basis is provided for improving laser output characteristics and perfecting resonantcavity design.

Description

technical field [0001] The invention relates to the field of lasers, in particular to a method and a device for obtaining the focal length and spherical aberration of a laser crystal thermal lens by inversion of wavefront information of a laser beam. Background technique [0002] The thermal effect of the laser crystal is an important factor affecting the laser performance of the laser, which directly affects the stability of the laser resonator, beam quality and output power. When the laser is working, part of the pump light is converted into output laser light, and the other part forms thermal deposition in the crystal. At this time, a temperature gradient will be generated, and the temperature gradient will lead to a refractive index gradient, so a thermal lens effect will occur. The wavefront distortion will occur after the laser passes through the thermal lens, so the thermal lens is not an ideal lens, but a lens with spherical aberration. In addition, when the pumping...

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Problems solved by technology

[0003] In order to solve the problem of incompleteness of the above-mentioned basic related parameters in the prior art, the present invention combines the adverse effects of the two on the laser output characteristics, and establishes a theoretical model between the wavefront information and the thermal lens focal length and spherical aberration. A method and device for inverting thermal lens focal length and spherical aberration at the same time based on wavefront information is proposed. The invention improves the problem of insufficient consideration of factors affecting beam quality, and more accurately analyzes the simultaneous existence of thermal lens effect and spherical aberration effect , the actual situation of simultaneous action

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