Method for improving stability of ultra-short laser frequency-doubling energy

Abstract

The invention relates to a method for improving the stability of ultra-short laser frequency-doubling energy. The method is characterized by comprising the following steps: (a) obtaining a curve of triple frequency conversion efficiency relative to the light intensity of fundamental-frequency light; (b) obtaining a range of light intensity corresponding to a decline part of the curve according to the decline part; and (c) adjusting the basic parameters of the fundamental-frequency light to enable the light intensity of the fundamental-frequency light to be within the range of light intensity. According to the invention, by selecting fundamental laser parameters (pulse energy, pulse width, and beam aperture) and crystal parameters, the frequency tripling process is enabled to work in an appropriate position of the decline part of the curve of triple frequency conversion efficiency, and thus the energy stability of triple-frequency light is significantly improved. The passive stability improving method breaks through the limit that the traditional triple-frequency light energy jitter is about three times the fundamental-frequency light energy jitter, the energy stability of triple-frequency light is obviously better than that of fundamental-frequency light, and the smoothness of transverse distribution and longitudinal distribution of triple-frequency light can be significantly improved.

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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