Space-time distortion-free laser pulse broadening method

Abstract

The invention discloses a space-time distortion-free laser pulse broadening method, which comprises the following steps of: firstly, selecting optical elements for pulse broadening, establishing a coordinate system, establishing an optical system for laser pulse broadening, adjusting the position relationship among the optical elements in the system, and then inputting a laser beam; outputting a laser beam after four-pass transmission in the system, wherein a plane mirror of the system completes conversion of the laser beam from the first pass to the second pass and from the third pass to thefourth pass, and a ternary fold-back mirror completes conversion of the laser beam from the second pass to the third pass. According to the space-time distortion-free laser pulse broadening method disclosed by the invention, a far-field optical element is prevented from being used in the laser pulse broadening process, so that the far-field signal-to-noise ratio of the laser is improved, and the light beam transmitted in the second path and the light beam transmitted in the third path are transmitted in an anti-parallel manner by utilizing the ternary reflector, Therefore, the problems of spatial chirp, angular dispersion and other spatial-temporal distortion of broadened laser beams are avoided, and the quality of output laser beams can be remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of ultra-short and ultra-intensive lasers, and in particular relates to a laser pulse stretching method without spatio-temporal distortion. Background technique [0002] Chirped pulse amplification technology is currently the main method to obtain ultra-short and ultra-intense laser pulses. It first broadens the ultra-short pulse on the time scale and reduces its peak power. Pulse stretching is an important step in chirped pulse amplification technology. [0003] The existing chirped pulse amplification system usually adopts the stretching method such as figure 2 As shown, for the incident laser light with a single wavelength component, a point focus is formed on the convex mirror 24, but when the laser pulse energy is high, the convex mirror 24 is easily damaged, thereby limiting the laser flux of the method, and the existing broadening In the method, the convex mirror 24 is used as the far-field element ...

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Problems solved by technology

[0003] The existing chirped pulse amplification system usually adopts the stretching method such as figure 2 As shown, for the incident laser light with a single wavelength component, a point focus is formed on the convex mirror 24, but when the laser pulse energy is high, the convex mirror 24 is easily damaged, thereby limiting the laser flux of the method, and the existing broadening In the method, the convex mirror 24 is used as the far-field element of the optical system, and the surface distortion of the convex mirror 24 will also significantly affect the far-field signal-to-noise ratio of the laser pulse. The amount of light off-axis in the vertical direction (Y-axis direction) is large ( figure 2 The middle stretcher adopts a four-pass structure, L is the off-axis amount), the output beam will produce obvious system spherical aberration, which will introduce space-time distortion problems such as spatial chirp and angular dispersion, which will seriously affect the quality of the beam after stretching

[0004] Therefore, in order to solve the problem of spatiotemporal distortion of the output beam after laser pulse stretching and improve the quality of the laser beam, a method is urgently needed to achieve laser pulse stretching without spatiotemporal distortion

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