Amplifier and method for increasing multipass amplifying output power of bar-like Nd: YAG (yttrium aluminum garnet) laser

Abstract

The invention relates to an amplifier and a method for increasing multipass amplifying output power of bar-like Nd: YAG (yttrium aluminum garnet) laser, belonging to the technical field of a laser device. A 1 / 2 wave plate, a polarized beam splitter a, a 45-degree faraday rotator, a 45-degree quartz rotator and a polarized beam splitter b are placed in sequence to form an opto-isolator, and a laser medium is installed in a semiconductor laser module. After seed light is injected, the seed light enters into the laser medium through the opto-isolator. The laser medium is an Nd: YAG crystal bar in a [100] cutting direction. After output, one-pass amplification is realized. The one-pass amplifying laser passes through a 1 / 4 wave plate and a total-reflecting mirror and then enters into the laser medium again, and two-pass amplifying laser is output through the polarized beam splitter b. When the laser enters into the laser medium, a direction in which the output power of linearly polarized light is a maximum value is selected as the direction of the crystal bar in the rotation range of 360 degrees. According to the amplifier and the method, the heat depolarization effect is obviously reduced, and additional loss brought by inserting a heat depolarization compensation device is avoided.

Description

technical field [0001] The invention relates to a multi-pass laser amplifier which uses a [100] direction to cut Nd:YAG crystal rods, and a method for finding the maximum output power of linearly polarized light by rotating the Nd:YAG crystal rods, belonging to the technical field of lasers. Background technique [0002] With the development of laser amplifiers, in order to achieve high output power, a multi-pass amplification structure must be used, and the laser must be linearly polarized. As the pump power and the number of times the laser passes through the laser medium increase, the thermal depolarization effect caused by thermally induced birefringence will increase significantly, seriously affecting the output power of the solid-state laser. In order to reduce the impact of thermal depolarization effect on the performance of laser amplifiers and seed source lasers, optical isolators are currently used to prevent depolarized light from returning to the seed source lase...

AI Technical Summary

Problems solved by technology

As the pump power and the number of times the laser passes through the laser medium increase, the thermal depolarization effect caused by thermally induced birefringence will increase significantly, seriously affecting the output power of the solid-state laser

In order to reduce the impact of thermal depolarization effect on the performance of laser amplifiers and seed source lasers, optical isolators are currently used to prevent depolarized light from returning to the seed source laser, but this method cannot reduce the thermal depolarization effect of laser amplifiers

[0003] In the prior art, the rod-shaped Nd:YAG laser multi-pass amplifier uses the [111] direction cut Nd:YAG crystal rod as the gain medium, and its thermal depolarization loss is relatively large during the multi-pass amplification process.

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