Method and device for testing nonlinear effect I * L value of optical element

Abstract

The invention discloses a method and a device for testing a nonlinear effect I * L value of an optical element. According to the method, a laser beam is focused in an optical element body by using a lens of which the focal length is smaller than the thickness of the optical element and adjusting the position of the optical element; meanwhile, the laser energy density of laser irradiation on the incident plane of the optical element to be measured is adjusted to be smaller than the laser damage threshold value of the incident plane of the optical element to be measured; a disturbance-induced small-scale self-focusing effect under a non-focusing condition is simulated; in a traditional test method, an incident surface of an optical element is damaged before in-vivo self-focusing filamentation; therefore, the problems of scattering, defect absorption and other laser losses caused by the damage of the incident surface of the optical element are solved, the test precision is improved, and more help is provided for the safe use of the optical element in a high-power laser device and the improvement of the laser damage resistance of the material.

Description

technical field [0001] The invention relates to the technical field of optical detection, in particular to a method and device for testing the nonlinear effect I*L value of an optical element. Background technique [0002] In laser inertial confinement fusion, the filamentary damage of optical elements caused by the nonlinear small-scale self-focusing effect has become a bottleneck problem that limits the laser output power and increases the risk and cost of device operation. The small-scale self-focusing effect is due to the local instability of the beam caused by the phase and amplitude modulation of the laser during transmission in the nonlinear medium, which splits the beam into high-intensity filaments to induce material damage. The I*L value of a nonlinear medium is one of the important bases for evaluating its small-scale self-focusing effect. I is the peak power density of the incident laser, and L is the distance from the initiation point of filamentation damage to ...

AI Technical Summary

Problems solved by technology

[0005] In view of this, the present invention provides a method and device for testing the nonlinear effect I*L value of an optical element. By adopting the method of focusing the laser beam in the optical element body, the disturbance-induced small-scale self-improvement under non-focusing conditions is simulated. The focus effect solves the problem of laser loss such as scattering and defect absorption caused by the damage of the incident surface of the optical element in the traditional test method because the damage of the incident surface of the optical element occurs before the self-focusing filament damage in the body, which not only improves the test accuracy , and also provide more help for the safe use of optical components in high-power laser devices and to improve the ability of materials to resist laser damage

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