Laser pulse compression device based on multiple cavities

Abstract

A kind of multipass cell-based laser pulse post-compression device, it is constituted in the direction of laser pulse advance in turn, mode matching module, nonlinear spectral broadening module, dispersion compensation module.This application can multiply compress the pulse width of high-power, high-energy, high-repetition industrial pulse laser, and the designed multipass cell oscillation mode will significantly improve the heat dissipation of mirror surface, expand the average power range of pulse laser that the device can adapt, and then multiply improve its peak power.

Description

Technical Field

[0001] This invention relates to the fields of laser technology and nonlinear optics, and more particularly to a pulsed laser compression device based on a multi-cavity cavity. Background Technology

[0002] With the development of science and technology, the demand for high-power, high-energy, and high-repetition-rate femtosecond lasers is becoming increasingly strong. Traditional Ti:sapphire femtosecond lasers cannot meet the high-power requirements, while other high-power pulsed lasers, such as ytterbium-doped pulsed lasers, can meet the requirements of high power, high energy, and high repetition rate. However, their pulse width is not as short as that of Ti:sapphire lasers. In order to improve the peak power of industrial pulsed lasers and quickly adapt them to industrial applications, it is necessary to further compress the pulsed laser time without changing the original laser structure. Therefore, it is necessary to design a post-pulse compression device for high-power, high-repetition-rate, and high-energy industrial lasers.

[0003] Traditional laser pulse compression techniques use hollow optical fibers filled with rare gases to achieve nonlinear spectral broadening of the pulse. However, the low damage threshold of hollow optical fibers is far from meeting the needs of high-power lasers used in industry. Therefore, multi-pass cavity structures have been proposed for spectral broadening of high-power lasers. The 2016 paper "Nonlinear pulse compression in a multi-pass cell" published in Opt. Lett by J. Schulte et al. details a pulse compression device based on a Herriott cell multi-pass cavity structure, successfully compressing a pulsed laser with an average power of 375W by 10 times, achieving an efficiency of over 90%.

[0004] However, further increasing the average power of the pulsed laser will inevitably cause heat accumulation and temperature rise in the mirror. The undesigned oscillation mode will not only have a limited number of oscillations, but the light spot will also repeatedly appear in the same position on the mirror surface, which will further increase the difficulty of heat dissipation and cause damage to the mirror. Summary of the Invention

[0005] To overcome the shortcomings of the prior art and optimize the heat dissipation capacity of the lens, the present invention provides a pulsed laser compression device based on a multi-cavity cavity. By designing a circular spot distribution, the spot is evenly distributed across the entire reflective mirror surface, making full use of the reflective mirror area for heat dissipation management.

[0006] The technical solution of the present invention is as follows:

[0007] A laser pulse compression device based on a multi-cavity cavity, characterized in that it includes:

[0008] The pattern matching module is used to change the spot size, shape and phase of the incident pulse so that the spot energy density is less than the damage threshold of the mirror in the nonlinear spectral broadening module.

[0009] The optical path coupling module is used to control the incident position and incident angle of the light spot coupling into the nonlinear spectral broadening module;

[0010] The nonlinear spectral broadening module includes at least a Herriott cell consisting of two relatively parallel concave mirrors with the same reflectivity and focal length, which cause the incident pulsed laser to oscillate multiple times in the Herriott cell. The incident position and incident angle of the pulsed laser are controlled by adjusting the optical path coupling module, so that a designed spot distribution pattern is presented on the two concave mirrors.

[0011] The dispersion compensation module is used to compensate for the chirp generated by the laser pulse after nonlinear broadening.

[0012] Preferably, after the pulsed laser is shaped by the mode matching module, it is input into the spectral broadening module. The nonlinear spectral broadening module consists of multiple mirrors, which cause the laser pulse to oscillate multiple times and broaden the spectrum by generating nonlinear interactions with the substances therein.

[0013] Preferably, the nonlinear spectral broadening module is used to compensate for the dispersion generated by the pulsed laser after nonlinear broadening. It consists of typical chirped mirror pairs, or transmission grating pairs, or reflection grating pairs as a chirping device, and its function is to compensate for the chirp generated by the pulsed laser in the nonlinear spectral broadening module.

[0014] Preferably, the multi-cavity structure provides a structure for multiple reflections of laser pulses, including a Herriott cell, a ring-shaped multi-cavity, and an array of multi-faceted mirrors. The designed spot pattern can also be applied to these structures to increase heat dissipation efficiency.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. By adopting a special light spot distribution pattern and utilizing the area of ​​the concave reflector, the number of oscillations in the multi-channel cavity is increased, the contact distance with the nonlinear material is multiplied, and the cumulative effect of nonlinear effects in a single multi-channel cavity is improved.

[0017] 2. By adopting a special spot distribution pattern and utilizing the area of ​​the concave mirror, the heat generated by the high-power laser is evenly distributed over a larger mirror area, making the thermal effect management of the high-power laser more effective. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the optical path of the multi-cavity pulsed laser compression device of the present invention.

[0019] Figure 2 This invention uses simulation software to calculate one of the light spot patterns that appear after a multi-cavity laser pulse is reflected multiple times on a concave mirror. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to specific examples and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The technical solutions provided by the format of this application are described in detail below with reference to the accompanying drawings.

[0022] Please see Figure 1 As shown, the pulsed laser compression device based on multi-cavity lasers in this application includes a mode matching module, which includes a first off-axis parabolic mirror 1, a high-power mirror 2, a second off-axis parabolic mirror 3, and a high-power mirror 4; a nonlinear spectral broadening module, which includes a first high-power concave mirror 8 and a second high-power concave mirror 9; and a dispersion compensation module, which includes a chirped mirror 12, a chirped mirror 13, and several other mirrors.

[0023] All the reflectors are high-power reflectors.

[0024] The pulsed laser emitted from the industrial laser first passes through the mode matching module, and is then reflected sequentially through the first off-axis parabolic mirror 1, the high-power mirror 2, the second off-axis parabolic mirror 3, and the high-power mirror 4, adjusting the laser spot to the required size. Afterward, it is reflected through the optical path coupling module, and after a single reflection through the high-power mirrors 5, 6, and 7, it is coupled into a multi-pass cavity based on a Herriott cell. By adjusting the position and pitch of the high-power mirrors 5, 6, and 7, the angle of incidence into the multi-pass cavity is controlled. Multiple reflections occur between the first high-power concave mirror 8 and the second high-power concave mirror 9, causing the oscillating light within the multi-pass cavity to travel n times (n is an integer) within the Herriott cell, forming a pattern as shown in the image. Figure 2 The light spot distribution pattern is shown. The high-power reflector 10 then reflects the oscillating light from the Herriott cell through the multi-channel cavity. After multiple reflections through the high-power reflector 11, the dispersion compensation module, the dispersion compensation mirror group (chirped reflector 12), and the chirped reflector 13, the light is finally reflected out by the high-power reflector group 14.

[0025] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0026] It should also be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or includes elements inherent to such a process, method, article, or apparatus that also contain other identical elements.

[0027] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A laser pulse compression device based on a multi-cavity cavity, characterized in that, include: The pattern matching module is used to change the spot size, shape and phase of the incident pulse so that the spot energy density is less than the damage threshold of the mirror in the nonlinear spectral broadening module, and to provide conditions for the spot to form a preset, non-overlapping distributed spot pattern on the multi-cavity mirror. The optical path coupling module is used to control the incident position and incident angle of the light spot coupling into the nonlinear spectral broadening module; The nonlinear spectral broadening module includes at least a Herriott cell consisting of two relatively parallel concave mirrors with the same reflectivity and focal length. The incident pulsed laser oscillates multiple times in the Herriott cell. By adjusting the mode matching module and the optical path coupling module, the incident position and incident angle of the pulsed laser are controlled, resulting in a designed spot distribution pattern on the two concave mirrors. This pattern is designed to uniformly distribute the heat load caused by the laser energy across the entire effective area of ​​the mirrors, thereby improving heat dissipation efficiency and allowing for higher average laser power. The dispersion compensation module is used to compensate for the chirp generated by the laser pulse after nonlinear broadening.

2. The laser pulse compression device based on a multi-cavity cavity as described in claim 1, characterized in that, After being shaped by the mode matching module, the pulsed laser is input into the spectral broadening module. The nonlinear spectral broadening module consists of multiple mirrors, which cause the laser pulse to oscillate multiple times and interact nonlinearly with the substances within it, thus broadening the spectrum.

3. The laser pulse compression device based on a multi-cavity cavity as described in claim 1, characterized in that, The nonlinear spectral broadening module is designed to compensate for the dispersion generated by the pulsed laser after nonlinear broadening. It consists of typical chirped mirror pairs, or transmission grating pairs, or reflection grating pairs as a chirping device, and its function is to compensate for the chirp generated by the pulsed laser in the nonlinear spectral broadening module.

4. The multi-cavity laser pulse compression device as described in claim 1, characterized in that, The multi-cavity structure provides a structure for multiple reflections of laser pulses, including a Herriott cell, a ring-shaped multi-cavity, and an array of multi-faceted mirrors. The designed spot pattern can also be applied to these structures to increase heat dissipation efficiency.

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