CN113437621A

CN113437621A - High-power laser time-space chirped pulse amplification system

Info

Publication number: CN113437621A
Application number: CN202110671420.2A
Authority: CN
Inventors: 张宗昕; 许毅; 冷雨欣; 吴分翔; 杨晓骏; 归佳彦; 钱佳毅
Original assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Current assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Priority date: 2021-06-17
Filing date: 2021-06-17
Publication date: 2021-09-24
Anticipated expiration: 2041-06-17
Also published as: CN113437621B

Abstract

A high-power laser space-time chirped pulse amplification system comprises a laser seed pulse source, a pulse time domain stretcher, a pulse space stretcher, a chirped pulse amplifier capable of being cascaded, a pulse space compressor and a pulse time domain compressor. The laser seed pulse source outputs seed pulses, the seed pulses are stretched into time-domain chirp pulses by a pulse time-domain stretcher, the time-domain chirp pulses are stretched into time-space chirp pulses by a pulse space stretcher, then the time-space chirp pulses are subjected to energy amplification and spectrum shaping by one or more cascade chirp pulse amplifiers, and the amplified time-space chirp pulses sequentially pass through a pulse space compressor and a pulse time-domain compressor to be compressed into ultrashort laser pulses. The system realizes spectrum shaping in the process of amplifying the space-time chirped pulse, can effectively inhibit spectrum narrowing and spectrum red shift in a CPA system, and avoids laser pulse energy loss caused by spectrum filtering and the limitation of the application condition of a filtering device.

Description

High-power laser time-space chirped pulse amplification system

Technical Field

The invention relates to high-power laser pulse amplification, in particular to a high-power laser space-time chirped pulse amplification system.

Background

In 1960, Maiman, the american Hughes laboratory, invented the first laser in the world. Then, Q-switching technique and mode-locking technique are rapidly developed, and the peak power of laser pulse reaches GW (10)⁹W) magnitude. When the laser power is continuously increased, nonlinear effects such as beam self-focusing are enhanced, and optical elements are easily damaged. In 1985, d.strickland and g.mourou at Rochester university in the united states applied chirped pulse amplification (hereinafter abbreviated as CPA) technology to solve the above problems well. The laser seed pulse is firstly stretched into chirp pulse in time domain, and the time domain chirp pulse is compressed into ultrashort laser pulse after energy amplification. The peak power of the laser pulse reaches TW (10) by using CPA technology¹²W) and even PW (10)¹⁵W) magnitude or more. For the conventional CPA technology, the time-domain chirped pulse will generate effects such as spectrum narrowing and spectrum red shift in the energy amplification process, thereby affecting the laser pulse width after compression. In order to suppress spectral narrowing and spectral red-shift, spectral filtering of the laser seed pulse is typically required in CPA systems (Physics, 2005(06): 2764-. However, spectral filtering will cause loss of laser pulse energy, and the filtering device needs to be suitable for certain laser conditions. Therefore, the limitation of the conventional CPA technology needs to be broken through, and the laser power output capability of the CPA system is further improved.

Disclosure of Invention

The invention provides a high-power laser space-time chirped pulse amplification system, which breaks through the limitations of spectrum narrowing and spectrum red shift effect in the traditional CPA system and promotes the improvement of the laser power output capability of the CPA system.

The technical solution of the invention is as follows:

a high-power laser space-time chirped pulse amplification system comprises a laser seed pulse source, a pulse time domain stretcher, a pulse time domain compressor, a pulse space stretcher, a cascadable chirped pulse amplifier and a pulse space compressor, wherein the cascadable chirped pulse amplifier comprises: the multi-channel pump laser pulse is widened into a time domain chirp pulse by the pulse time domain stretcher, the time domain chirp pulse is widened into a time-space chirp pulse by the pulse space stretcher, the multi-channel pump laser pulse is respectively reflected by the pump light reflectors and acts on the gain medium, and the time-space chirp pulse is reflected by the plurality of seed light reflectors and passes through the gain medium for multiple times; at the cross section of the gain medium, the multiple channels of pump laser pulses are sequentially arranged along the space chirp direction (i.e. the z-axis direction) of the time-space chirp pulse, and after the energy amplification and the spectrum shaping are carried out on the time-space chirp pulse by one or more cascade chirped pulse amplifiers, the time-space chirp pulse is compressed into an ultrashort laser pulse by sequentially passing through the pulse space compressor and the pulse time domain compressor.

The pulse space stretcher is a prism pair or a grating pair, the time domain chirp pulse generates space chirp vertical to a propagation main plane (namely an xy plane) after passing through the pulse space stretcher, and the pulse space compressor and the pulse space stretcher are symmetrical in structure and opposite in function.

The cascade chirped pulse amplifier can inhibit spectrum narrowing and spectrum red shift by adjusting the energy, polarization or time delay of the multi-channel pump laser pulses.

Compared with the prior art, the invention has the following remarkable characteristics:

1. by utilizing a space-time chirped pulse amplification technology, the multistage multi-pass amplification of the space-time chirped pulse can be realized, the spectrum narrowing and the spectrum red shift in a CPA system are inhibited, and the laser power output capability of the CPA system is improved;

2. in the process of amplifying the space-time chirped pulse, the spectral shaping of the space-time chirped pulse can be realized step by step, and the laser pulse energy loss and the limitation of the applicable condition of a filtering device caused by pre-compensation spectral filtering are avoided.

Drawings

FIG. 1 is a schematic diagram of the high-power laser space-time chirped pulse amplification system according to the present invention.

Fig. 2 is a schematic diagram of an optical path structure of the pulse space stretcher in the embodiment.

Fig. 3 is a schematic diagram of an optical path structure of the cascade multi-pass chirped pulse amplifier in the embodiment.

Fig. 4 is a schematic diagram of the spatial arrangement of the pump laser pulses and the space-time chirped pulses at the cross section of the gain medium in the embodiment.

Detailed Description

The present invention is further illustrated by the following examples and figures, but should not be construed as being limited thereby.

Referring to fig. 1 and fig. 3, fig. 1 is a schematic structural diagram of a high-power laser space-time chirped pulse amplification system according to the present invention. Fig. 3 is a schematic diagram of an optical path structure of the cascade multi-pass chirped pulse amplifier in the embodiment. It can be seen from the figure that the high-power laser space-time chirped pulse amplification system of the present invention comprises a laser seed pulse source 1, a pulse time domain stretcher 2, a pulse time domain compressor 6, a pulse space stretcher 3, a cascadable chirped pulse amplifier 4 and a pulse space compressor 5, wherein the cascadable chirped pulse amplifier 4 comprises: a multi-pumping laser pulse P1, P2, P3, P4, …, a plurality of

pumping mirrors

401, 402, 403, 404, a gain medium 405, a plurality of

seed mirrors

413, 412, 411, 410, 409, 408, 407, 406, wherein the seed pulse C0 is broadened into a time-domain chirped pulse C1 by the pulse time-domain stretcher 2, the time-domain chirped pulse C1 is broadened into a time-space chirped pulse C2 by the pulse space stretcher 3, the multi-pumping laser pulse P1, P2, P3, P4, … is reflected by the

pumping mirrors

401, 402, 403, 404 respectively and acts on the gain medium 405, and the time-space chirped pulse C2 passes through the gain medium 405 a plurality of times by the plurality of

seed mirrors

413, 412, 411, 410, 409, 408, 407, 406; at the cross section of the gain medium 405, the multiple pump laser pulses P1, P2, P3, P4, … are sequentially arranged along the spatial chirp direction (i.e., z-axis direction) of the space-time chirped pulse C2, and after the energy amplification and spectral shaping of the space-time chirped pulse C2 are performed by one or more cascadable chirped pulse amplifiers 4, the space-time chirped pulse C2 is compressed into an ultrashort laser pulse by sequentially passing through the pulse space compressor 5 and the pulse time domain compressor 6.

The pulse space stretcher 3 is a prism pair or a grating pair, the time domain chirped pulse C1 generates a spatial chirp perpendicular to a propagation main plane (namely, xy plane) of the time domain chirped pulse after passing through the pulse space stretcher 3, and the pulse space compressor 5 is structurally symmetrical and has an opposite function with the pulse space stretcher 3.

The pulse time domain stretcher 2 and the pulse time domain compressor 6 can respectively adopt

Type stretchers and Treacy type compressors.

Referring to fig. 2, fig. 2 is a schematic diagram of an optical path structure of a pulse space stretcher in an embodiment. As can be seen from the figure, the time-domain chirped pulse C1 is stretched into a space-time chirped pulse C2 after passing through the first prism 301 and the second prism 302 in sequence along the x-axis direction, and the space-time chirped pulse C2 has a spatial chirp along the z-axis direction. The incident surface of the first prism 301 is parallel to the exit surface of the second prism 302, and the exit surface of the first prism 301 is parallel to the incident surface of the second prism 302. The pulse space compressor 5 and the pulse space stretcher 3 are symmetrical in structure and opposite in function.

Fig. 4 is a schematic diagram of the spatial arrangement of the pump laser pulses and the space-time chirped pulses at the cross section of the gain medium in the embodiment. P1, P2, P3 and P4 are multi-channel pump laser pulses, C2 is a space-time chirped pulse, and 405 is a gain medium.

Experiments show that the invention realizes the spectrum shaping in the process of amplifying the space-time chirped pulse, can effectively inhibit the spectrum narrowing and the spectrum red shift in a CPA system, and avoids the laser pulse energy loss caused by spectrum filtering and the limitation of the application condition of a filtering device.

Claims

1. A high-power laser space-time chirped pulse amplification system comprises a laser seed pulse source (1), a pulse time domain stretcher (2) and a pulse time domain compressor (6), and is characterized by further comprising a pulse space stretcher (3), a cascadable chirped pulse amplifier (4) and a pulse space compressor (5), wherein the cascadable chirped pulse amplifier (4) comprises: multiple pump laser pulses (P1, P2, P3, P4, …), a plurality of pump light mirrors (401, 402, 403, 404), a gain medium (405), a plurality of seed light mirrors (413, 412, 411, 410, 409, 408, 407, 406), the seed pulse (C0) is stretched into a time domain chirp pulse (C1) by the pulse time domain stretcher (2), the time domain chirp pulse (C1) is stretched into a time-space chirp pulse (C2) by the pulse space stretcher (3), the multi-channel pumping laser pulses (P1, P2, P3, P4, …) are respectively reflected by the pumping light reflecting mirrors (401, 402, 403, 404) and then act on the gain medium (405), said space-time chirped pulse (C2) is reflected off a plurality of seed light mirrors (413, 412, 411, 410, 409, 408, 407, 406) a plurality of times through said gain medium (405); at the cross section of the gain medium (405), the multiple pump laser pulses (P1, P2, P3, P4, …) are sequentially arranged along the spatial chirp direction (i.e. z-axis direction) of the space-time chirped pulse (C2), after the energy amplification and the spectral shaping of the space-time chirped pulse (C2) by one or more cascadable chirped pulse amplifiers (4), the space-time chirped pulse (C2) is compressed into an ultrashort laser pulse by sequentially passing through the pulse space compressor (5) and the pulse time domain compressor (6).

2. The high power laser space-time chirped pulse amplification system according to claim 1, wherein said pulse space stretcher (3) is a prism pair or a grating pair, the time domain chirped pulse (C1) generates a space chirp perpendicular to its main propagation plane (xy plane) after passing through the pulse space stretcher (3), and said pulse space compressor (5) is structurally symmetrical and opposite in function to said pulse space stretcher (3).

3. The high power laser space-time chirped pulse amplification system according to claim 1, wherein the cascadable chirped pulse amplifier (4) can suppress spectral narrowing and spectral red shift by adjusting energy, polarization or delay of the multi-pump laser pulses (P1, P2, P3, P4, …).