High-power laser nonlinear compression device based on composite film reflector

Abstract

A high-power laser nonlinear compression device based on composite film layer reflectors comprises at least one composite film layer reflector, each composite film layer reflector is composed of an anti-reflection film layer, a nonlinear dielectric film layer, a chirp reflection film layer and a lens substrate, and laser pulses firstly enter the anti-reflection film layers of the composite film layer reflectors and then enter the nonlinear dielectric film layers of the composite film layer reflectors. Then the laser pulse enters the nonlinear dielectric film layer for spectrum broadening, dispersion compensation and light reflection are realized through the chirp reflection film layer, and the reflected laser pulse is emitted as a shorter pulse through the nonlinear dielectric film layer and the antireflection film layer again; the negative dispersion amount generated by the laser pulse passing through the chirp reflection film layer and the positive dispersion amount generated by the laser pulse passing through the nonlinear dielectric film layer and the antireflection film layer twice are compensated. The structure is simple, spectrum broadening and dispersion compensation can be achieved at the same time through the composite film layer reflecting mirror, and further improvement of laser pulse nonlinear compression efficiency is better facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of nonlinear compression of high-power laser pulses, in particular to a high-power laser nonlinear compression device based on a composite film reflector. Background Art

[0002] With the continuous development of chirped pulse amplification (CPA) technology, the peak power of laser pulses can reach TW (10 12 W) or even PW(10 15 In 2014, G. Mourou and his research team proposed a high-power laser nonlinear compression technology using large-aperture nonlinear dielectric materials and chirped mirrors. This technology is expected to increase the peak power of laser pulses to nearly EW (10 18 W) level (Eur. Phys. J. Spec. Top. 2014, 223:1181). In 2019, VN Ginzburg et al. used large-aperture glass materials to compress high-power laser pulse width from 63 fs to 21 fs (Quantum Electronics, 2019, 49:299). In 2022, JIKIM et al. used large-aperture quartz materials to compress high-power laser pulse width from 23 fs to below 10 fs (Optics Express, 2022, 30:8734). In these high-power laser nonlinear compression technologies, the laser pulse is first spectrally broadened by passing through a large-aperture thin-film material such as glass or quartz, and then dispersion is compensated for using a chirped mirror to further compress the laser pulse width. The large-aperture thin-film material is difficult to process and must be used in conjunction with a chirped mirror.

[0003] Therefore, it is necessary to develop new high-power laser nonlinear compression devices to further improve the nonlinear compression efficiency of high-power lasers. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the existing technology, the present invention provides a high-power laser nonlinear compression device based on a composite film layer reflector. The composite film layer reflector can simultaneously achieve spectral broadening and dispersion compensation, which is conducive to further improving the efficiency of high-power laser nonlinear compression.

[0005] The technical solutions of the present invention are as follows:

[0006] A high-power laser nonlinear compression device based on a composite film reflector is characterized in that it includes at least one composite film reflector, each composite film reflector consisting of a four-layer structure:

[0007] The upper layer is an anti-reflection film layer, which is used to reduce the reflection loss of the incident laser;

[0008] The middle layer is a nonlinear dielectric film layer, which is made of materials such as TiO2 or Ta2O5 with high nonlinear refractive index coefficient;

[0009] The lower layer is a chirped reflective film layer, which is used to achieve dispersion compensation and light reflection;

[0010] The bottom layer is the lens substrate, which is made of optical glass or crystal material.

[0011] The laser pulse first enters the anti-reflection film layer of the composite film reflector, then enters the nonlinear dielectric film layer for spectral broadening, and then passes through the chirped reflective film layer to achieve dispersion compensation and light reflection. The reflected laser pulse passes through the nonlinear dielectric film layer and the anti-reflection film layer again and is emitted as a shorter pulse. The negative dispersion generated by the laser pulse passing through the chirped reflective film layer is compensated by the positive dispersion generated by passing through the nonlinear dielectric film layer and the anti-reflection film layer twice.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. The device has a relatively simple structure, consisting of only one or more composite film reflectors, each of which can achieve nonlinear compression of laser pulses;

[0014] 2. Integrating spectral broadening and dispersion compensation functions into a single reflector simplifies the system structure and achieves optimal compression by precisely matching the negative dispersion of the chirped reflective film with the positive dispersion of the nonlinear dielectric film.

[0015] 3. Use multiple mirrors in series to achieve multi-stage compression, further improving the nonlinear compression efficiency of high-power laser pulses. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of a high-power laser nonlinear compression device composed of two composite film layer reflectors in an embodiment.

[0017] Figure 2 Schematic diagram of the film structure of the composite film reflector. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to examples and drawings, but the scope of protection of the present invention should not be limited thereto.

[0019] like Figure 1 As shown in FIG, this embodiment uses a high-power laser nonlinear compression device composed of two composite film reflectors M1 and M2 connected in series to perform nonlinear compression on the laser pulse P0. The peak power of the laser pulse P0 is 1PW, the spectral width is 760-830nm, and the initial pulse width is 30fs. The specific structure of each composite film reflector is as follows: Figure 2 As shown, from top to bottom, it includes:

[0020] Anti-reflection coating M-1: has high transmittance in the 650-1050nm spectral range;

[0021] Nonlinear dielectric film layer M-2: Ta2O5 material can be used, and the film thickness is 16.9μm;

[0022] Chirped reflective film M-3: has high reflectivity in the 650-1050nm spectral range and can provide negative dispersion that matches the positive dispersion produced by the nonlinear dielectric film M-2 and the antireflection film M-1.

[0023] Lens substrate M-4: can be made of quartz glass.

[0024] The two-stage nonlinear compression process in this embodiment is:

[0025] First level compression:

[0026] The high-power laser pulse P0 (initial pulse width ~30fs) is incident on the anti-reflection film layer M-1 of the first composite film layer reflector M1, then enters the nonlinear dielectric film layer M-2 for spectral broadening, and then passes through the chirped reflective film layer M-3 to achieve dispersion compensation and light reflection. The reflected laser pulse P0 is emitted through the nonlinear dielectric film layer M-2 and the anti-reflection film layer M-1 in turn, outputting a shorter pulse P1 (pulse width ~11.3fs).

[0027] Second level compression:

[0028] The pulse P1 is incident on the second composite film reflector M2, and the above nonlinear compression process is repeated, and the pulse width of the final output pulse P2 is compressed to ~8.6fs.

[0029] This device can effectively compress the pulse width of high-power lasers while maintaining high energy conversion efficiency. By optimizing the film material and thickness parameters, it can adapt to the requirements of laser pulse compression for different wavelengths, pulse widths, and powers. To achieve shorter pulse widths and higher peak powers, multiple mirrors can be connected in series to achieve progressive compression. This invention is particularly suitable for ultrashort pulse laser systems and provides a more efficient and compact technical solution for the further application of high-power lasers.

Claims

1. A high-power laser nonlinear compression device based on a composite film reflector, characterized in that: The invention comprises at least one composite film layer reflector, wherein the composite film layer reflector comprises an antireflection film layer (M-1), a nonlinear dielectric film layer (M-2), a chirped reflective film layer (M-3) and a lens substrate (M-4) stacked in sequence; The laser pulse passes through the anti-reflection film layer (M-1) and the nonlinear medium film layer (M-2) in sequence for spectral broadening, then is reflected by the chirped reflective film layer (M-3) and dispersion compensation, and finally passes through the nonlinear medium film layer (M-2) and the anti-reflection film layer (M-1) again to be emitted, thereby achieving pulse compression.

2. The high-power laser nonlinear compression device based on a composite film reflector according to claim 1, characterized in that: The nonlinear dielectric film layer (M-2) is made of dielectric material with a high nonlinear refractive index coefficient, including TiO2 or Ta2O5.

3. The high-power laser nonlinear compression device based on a composite film reflector according to claim 1, characterized in that: The negative dispersion provided by the chirped reflective film layer (M-3) matches the positive dispersion generated by the laser pulse passing through the nonlinear medium film layer (M-2) and the antireflection film layer (M-1) twice, thereby achieving dispersion compensation.

4. The high-power laser nonlinear compression device based on a composite film reflector according to claim 1, characterized in that: It comprises a plurality of composite film layer reflectors, and the laser pulse passes through each composite film layer reflector in sequence for multi-stage compression.

5. The high-power laser nonlinear compression device based on a composite film reflector according to claim 1, characterized in that: The antireflection film layer (M-1) is used to reduce the reflection loss of the incident laser and improve the nonlinear compression efficiency.

6. The high-power laser nonlinear compression device based on a composite film reflector according to claim 1, characterized in that: The lens substrate (M-4) is optical glass or crystal material, and is used to support the composite film layer structure.

Images