A method to improve the energy stability of ultrashort laser frequency doubling

Abstract

The present invention relates to a method for improving the energy stability of ultra-short laser triple frequency, which is characterized by the following steps: (a) obtaining the curve of triple frequency conversion efficiency relative to the light intensity of fundamental frequency light; (b) according to For the descending portion of the above curve, a light intensity range corresponding to the descending portion is obtained; (c) adjusting basic parameters of the fundamental frequency light so that the light intensity of the fundamental frequency light is within the light intensity range. According to the present invention, by selecting the fundamental frequency laser parameters (pulse energy, pulse width, beam aperture) and crystal parameters, the triple frequency process can be operated at a suitable position in the descending section of the triple frequency efficiency curve, thereby significantly improving the triple frequency The energy stability of light, this passive stability method breaks through the limitation of the traditional triple-frequency light energy jitter is about three times the fundamental frequency light energy jitter, so that the energy stability of the triple-frequency light is significantly better than the fundamental frequency light , and can also remarkably improve the smoothness of the lateral distribution and longitudinal distribution of the tripled frequency light at the same time.

Description

technical field [0001] The invention relates to a method for improving the energy stability of ultrashort laser frequency doubling, in particular to a method for improving the energy stability of ultrashort laser triple frequency. Background technique [0002] It is generally believed that since the triple frequency of the ultrashort laser is a third-order nonlinear process, the energy jitter of the tripled output is close to three times the jitter of the fundamental frequency laser. Generally, the fundamental frequency light energy output by a laser system based on a multi-pass amplifier can reach 2% root mean square energy stability. According to the common understanding, the energy stability of the generated triple frequency light will deteriorate to the fluctuation of the fundamental frequency light energy jitter. Three times, this brings great limitations to applications such as photocathode injectors that require high energy stability of ultra-short ultraviolet lasers....

AI Technical Summary

Problems solved by technology

Generally, the fundamental frequency light energy output by a laser system based on a multi-pass amplifier can reach 2% root mean square energy stability. According to the common understanding, the energy stability of the generated triple frequency light will deteriorate to the fluctuation of the fundamental frequency light energy jitter. Three times, this brings great limitations to applications such as photocathode injectors that require high energy stability of ultra-short ultraviolet lasers. For example, Linac Coherent Light Source (LCLS) requires that the energy jitter of the ultraviolet light driving the photocathode is less than 2% rms, the energy jitter design index of FER-MI system ultraviolet light is less than 3% rms

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