Optical film defect laser damage threshold test method

Abstract

The invention discloses an optical film defect laser damage threshold test method. According to the method, after a laser beam passes through an attenuator and arrives at a beam splitter, and the laser beam in the transmission direction of the beam splitter passes through a focusing lens and arrives at a metal film; a CCD camera records a spot position where the laser irradiates on the surface ofthe metal film and a laser damage point coordinate where the laser irradiates on the surface of the optical film; and a scanning electron microscope records the longitudinal depth position of the defect damage point of the optical film in the irradiation of the laser and completes a defect damage point lateral energy density subdivision and longitudinal electric field normalization processing-combined analysis. In an optical film defect laser damage threshold test in the prior art, randomly-distributed defect damage points and laser energy density of Gaussian distribution in a laser spot are considered to be uniformly-distributed damage points and laser energy density equivalently, and influence on the defect damage point caused by the electric field distribution of the optical film is ignored, and as a result, many problems are brought about, while with the optical film defect laser damage threshold test method of the invention adopted, the above problems can be solved, and test accuracy can be improved.

Description

technical field [0001] The invention belongs to the field of optical detection, in particular to a method for testing the laser damage threshold of optical film defects. Background technique [0002] Optical thin films are widely used in high-power laser systems, but the laser damage of optical thin films has always been a bottleneck limiting their development. An accurate laser damage threshold not only provides a safe range of use for optical films, but also a prerequisite for research on how to improve their resistance to laser damage. [0003] Under long-pulse laser irradiation, the laser damage of optical films is mainly caused by the defects in the optical films, and the laser damage threshold caused by defects is much smaller than the laser damage threshold corresponding to intrinsic damage. However, the international standard laser damage threshold test method regards the uneven distribution of defect damage as equivalent to the Gaussian distribution of laser energy...

AI Technical Summary

Problems solved by technology

[0002] Optical thin films are widely used in high-power laser systems, but the laser damage of optical thin films has always been a bottleneck limiting its development

For optical thin films, the electric field distribution is mainly modulated by the film structure, and the electric field intensities suffered by defects at different depths in optical thin films are also different, and the international standard laser damage threshold test method also does not affect the defects in optical thin films. Analysis of the influence of the electric field on the damage

[0004] Since the existing laser damage threshold test method is difficult to guarantee the accuracy of the damage threshold test for optical film defects, it is necessary to invent a defect damage threshold test method for optical films under long-pulse laser irradiation

Images