A device and method for measuring thermal focal length of laser medium

Abstract

The invention discloses a device and method for measuring the thermal focal length of a laser medium, belonging to the technical field of lasers. Including a rear reflector, a laser medium to be measured, a cat's eye module, a photodetector, a mounting frame for installing the cat's eye module and the photodetector; the distance between the focusing lens and the plano-convex lens in the cat's eye module can be adjusted; The optical detector is set on the focal point of the convex surface of the plano-convex lens, and the critical point of the stable state and unstable state of the laser is found through the optical detector, and the laser medium to be tested is read on the stable zone diagram according to the distance between the focusing lens and the plano-convex lens thermal focal length. The invention is suitable for end-pumped and side-pumped laser media, adopts an optical resonant cavity that is not sensitive to angles to realize the arrangement of fast measuring devices, and can realize the measurement of thermal focal lengths of different laser media in a longer wavelength range, and at the same time It is also easy to extend to laser media of different wavelength bands.

Description

technical field [0001] The invention relates to the field of laser technology, in particular to a device and method capable of quickly measuring the focal length of a laser medium thermal lens with strong adaptability. [0002] technical background [0003] Solid-state lasers are widely used in military, processing, medical and scientific research fields due to their small size, convenient use, high output power, and good beam quality. In the working state of the solid-state laser, only a small part of the pump energy absorbed by the laser crystal as the gain medium is converted into laser output, and most of the remaining energy is absorbed by the laser crystal, forming a temperature gradient inside the crystal. The temperature gradient and thermal strain photoelasticity of the laser crystal lead to the uneven distribution of the refractive index inside the crystal, which produces a focusing effect similar to a focusing lens for the passing laser beam, which is called the th...

AI Technical Summary

Problems solved by technology

The disadvantage is that the resonant cavity needs to be built multiple times for different thermal focal lengths, and the flat cavity structure has high requirements on the parallelism of the cavity mirror, which makes it difficult to adjust and realize automatic control, which is time-consuming and laborious

The principle of this method is simple, but in actual operation, due to the small light spot and long depth of focus, it is difficult to determine the specific position of the focus, so the measurement result of this method is not accurate, or the measurement process is very complicated

In addition, because the probe light is different from the actual output laser wavelength, the measured thermal focal length and the actual wavelength will also cause a certain difference

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