CN-116316027-B - Eight-way pulse stretcher

CN116316027BCN 116316027 BCN116316027 BCN 116316027BCN-116316027-B

Abstract

The application provides an eight-way pulse stretcher, which comprises a circulator, a collimator, a polarization beam splitter, a two-way transmission type single-grating stretching unit, a beam shrinking unit, a quarter wave plate, a first 0-degree reflecting mirror and a second 0-degree reflecting mirror. The pulse stretcher of the application realizes four times of pulse passing through the two-way transmission type single grating stretching unit, thereby realizing large stretching quantity of optical pulses, being simpler, more reliable and practical than the existing active switching mode, and avoiding the problem of increasing the amplified noise at the rear end of the pulse stretcher. The pulse stretcher of the application has compact structure and high stability, does not need switch control, can stretch the pulse to ns magnitude, and is very suitable for stretching and amplifying high-energy pulse. The pulse stretcher of the application adopts the circulator and the collimator to realize the optical fiber input and output of the optical pulse, thereby greatly improving the accessibility of the stretcher and leading the stretcher to be very suitable for being embedded into a high-energy laser system.

Inventors

ZOU SI
WAN WEI
HE FEI
CHEN KANGKANG

Assignees

武汉安扬激光技术股份有限公司

Dates

Publication Date: 20260505
Application Date: 20230203

Claims (9)

1. The eight-way pulse stretcher is characterized by comprising a circulator, a collimator, a polarization beam splitter, a two-way transmission type single-grating stretching unit, a beam shrinking unit, a quarter wave plate, a first 0-degree reflecting mirror and a second 0-degree reflecting mirror; The light pulse is input from the input end of the circulator, enters the polarization beam splitter after being collimated by the collimator and is output as polarized light in a first state, the polarized light pulse in the first state passes through the two-way transmission type single-grating widening unit for the first time, passes through the beam shrinking unit, the quarter wave plate and the first 0-degree reflecting mirror, and is converted into polarized light in a second state; The second-state polarized light pulse passes through the two-way transmission type single grating widening unit for the second time, and returns after passing through the polarizing beam splitter and the second 0-degree reflecting mirror; Returning the optical pulse to pass through the two-way transmission type single grating widening unit for the third time, and then passing through the beam shrinking unit, the quarter wave plate and the first 0-degree reflecting mirror again, wherein the second-state polarized optical pulse is converted into the first-state polarized optical pulse; The polarized light pulse in the first state passes through the two-way transmission type single grating widening unit for the fourth time, is coupled into the circulator through the polarization beam splitter and the collimator, and is output from the output end of the circulator; The first state polarized light is polarized light in a horizontal polarization state or a vertical polarization state, and the second state polarized light is perpendicular to the first state polarized light; The two-way transmission type single-grating widening unit comprises a transmission grating, a concave reflecting mirror and a plane reflecting mirror, wherein the transmission grating is arranged between the concave reflecting mirror and the plane reflecting mirror.
2. The eight-way pulse stretcher of claim 1 wherein said transmission grating is insensitive to light polarization.
3. The eight-pulse stretcher of claim 2 wherein said transmission grating comprises two sub-transmission gratings and a half-wave plate, said half-wave plate being disposed in parallel between two of said sub-transmission gratings.
4. An eight-way pulse stretcher as defined in claim 3 wherein the parameters of both said sub-transmission gratings are identical.
5. The eight-way pulse stretcher of claim 1 wherein the distance between said concave mirror and said planar mirror is equal to the focal length of said concave mirror.
6. The eight-way pulse stretcher of claim 1 wherein said beam shrinking unit comprises a convex cylindrical mirror and a concave cylindrical mirror arranged in parallel.
7. The eight-way pulse stretcher of claim 6 wherein said convex cylindrical mirror and said concave cylindrical mirror are arranged at a confocal distance.
8. The eight-way pulse stretcher of claim 1, wherein the polarizing beam splitter is a polarizing beam splitter plate or a polarizing beam splitter prism.
9. The eight-way pulse stretcher of claim 1, wherein said collimator is an aspheric lens.

Description

Eight-way pulse stretcher Technical Field The application belongs to the technical field of lasers, and particularly relates to an eight-channel pulse stretcher. Background Chirped Pulse Amplification (CPA) technology is a relatively common technology in the field of high energy ultrafast lasers. How to obtain a stretcher with a high stretching amount by a smaller cost and a compact structure for pulse stretching is always the subject of study of CPA technology. Chinese patent CN102866557B, CN109407354A achieves multiple stretching of pulses in the stretcher by introducing electro-optical switches in the stretcher, chinese patent CN103001107a achieves multiple stretching of pulses in the stretcher by introducing acousto-optic modulators in the stretcher. The common characteristic of the two-stage pulse stretcher is that the multiple stretching of the pulse in the stretcher is realized by an active switch control mode, the requirements on devices and electric control are very high, small pulses are very easy to appear, and the amplification noise of the rear end is increased. Disclosure of Invention The application aims to provide an eight-way pulse stretcher, which solves the technical problem that the back end amplification noise is increased due to the fact that multiple stretching of pulses in the stretcher is realized in an active switch control mode in the prior art. In order to achieve the aim, the technical scheme adopted by the application is that the eight-channel pulse stretcher comprises a circulator, a collimator, a polarization beam splitter, a two-way transmission type single-grating stretching unit, a beam shrinking unit, a quarter wave plate, a first 0-degree reflecting mirror and a second 0-degree reflecting mirror; The light pulse is input from the input end of the circulator, enters the polarization beam splitter after being collimated by the collimator and is output as polarized light in a first state, the polarized light pulse in the first state passes through the two-way transmission type single-grating widening unit for the first time, passes through the beam shrinking unit, the quarter wave plate and the first 0-degree reflecting mirror, and is converted into polarized light in a second state; The second-state polarized light pulse passes through the two-way transmission type single grating widening unit for the second time, and returns after passing through the polarizing beam splitter and the second 0-degree reflecting mirror; Returning the optical pulse to pass through the two-way transmission type single grating widening unit for the third time, and then passing through the beam shrinking unit, the quarter wave plate and the first 0-degree reflecting mirror again, wherein the second-state polarized optical pulse is converted into the first-state polarized optical pulse; The polarized light pulse in the first state passes through the two-way transmission type single grating widening unit for the fourth time, is coupled into the circulator through the polarization beam splitter and the collimator, and is output from the output end of the circulator; the first state polarized light is polarized light in a horizontal polarization state or a vertical polarization state, and the second state polarized light is perpendicular to the first state polarized light. Further, the two-way transmission type single-grating widening unit comprises a transmission grating, a concave reflecting mirror and a plane reflecting mirror, wherein the transmission grating is arranged between the concave reflecting mirror and the plane reflecting mirror. Further, the transmission grating is insensitive to the polarization state of the light. Further, the transmission grating comprises two sub-transmission gratings and a half-wave plate, and the half-wave plate is arranged between the two sub-transmission gratings in parallel. Further, the parameters of the two sub-transmission gratings are identical. Further, a distance between the concave mirror and the planar mirror is equal to a focal length of the concave mirror. Further, the beam shrinking unit comprises a convex cylindrical mirror and a concave cylindrical mirror which are arranged in parallel. Further, the convex cylindrical lens and the concave cylindrical lens are arranged at a confocal distance. Further, the polarization beam splitter is a polarization beam splitter flat plate or a polarization beam splitter prism. Further, the collimator is an aspherical lens. Compared with the prior art, the application has the following technical effects: According to the eight-channel pulse stretcher, the polarization state of the optical pulse is changed through the quarter wave plate, the first 0-degree reflecting mirror and the second 0-degree reflecting mirror, and the polarization beam splitter is combined, so that the four-pass two-way transmission type single-grating stretcher unit of the pulse is realized, the large stretching quantity of the optical pul