A device for shortening the optical path of femtosecond laser pulses

Abstract

This application provides a femtosecond laser pulse compression device for shortening optical path, comprising a mode-locked seed source, a beam stretcher, a timing adjustment module, and an fiber amplifier arranged sequentially along the optical path; the pulse compression module includes a first transmission grating and a second transmission grating that are parallel to each other; a reflector is also provided between the first transmission grating and the fiber amplifier; a plano-concave cylindrical mirror and a plano-convex cylindrical mirror are respectively provided between the second transmission grating and the first transmission grating; the plano-concave cylindrical mirror is relatively close to the first transmission grating; the plano-convex cylindrical mirror is located between the plano-concave cylindrical mirror and the second transmission grating; a beam-raising mirror is also provided on the side of the second transmission grating away from the plano-convex cylindrical mirror. By setting the plano-concave cylindrical mirror and the plano-convex cylindrical mirror between the first transmission grating and the second transmission grating respectively, the optical path can be effectively reduced, the optical path divergence angle can be expanded, and the diffracted light divergence path can be reduced, thereby realizing the miniaturization of the femtosecond laser.

Description

Technical Field

[0001] This application relates to the field of ultrafast laser technology, specifically to a device for shortening the optical path of a femtosecond laser pulse compression. Background Technology

[0002] In femtosecond laser technology, achieving narrower pulse widths relies heavily on chirped pulse amplification (CPA), which essentially involves first broadening the pulse time domain using a stretcher and then compressing it using a compressor. With the widespread application in industry and scientific research, the demand for high peak power femtosecond lasers is increasingly strong. Obtaining high peak power femtosecond lasers requires narrower pulse widths and higher single-pulse energy. However, narrower pulse widths are generally achieved through fiber amplification. Achieving high single-pulse energy using fiber amplification necessitates increasing the stretching amount of the stretcher to reduce nonlinear effects during amplification. A larger stretching amount, in turn, requires a larger compression amount to match. In femtosecond lasers, the compressed volume can account for about one-third of the total volume. A smaller compressed volume effectively reduces the overall laser size, which is beneficial for stable and long-term laser operation. Therefore, increasing the stretching amount while reducing the compressed volume is crucial for femtosecond laser development. Summary of the Invention

[0003] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a femtosecond laser pulse compression device that shortens the optical path.

[0004] This application provides a device for shortening the optical path of a femtosecond laser pulse compression, including: The mode-locked seed source, stretcher, timing adjustment module and fiber amplifier are arranged sequentially along the optical path; A pulse compression module, comprising a first transmission grating and a second transmission grating that are parallel to each other; A reflector is also provided between the first transmission grating and the fiber amplifier to change the direction of the optical path and thus compress the volume. A plano-concave cylindrical mirror and a plano-convex cylindrical mirror are respectively provided between the second transmission grating and the first transmission grating; The plano-concave cylindrical mirror is positioned relatively close to the first transmission grating to expand the laser beam incident through the first transmission grating. The plano-convex cylindrical mirror is located between the plano-concave cylindrical mirror and the second transmission grating, and is used to collimate the expanded laser beam. The second transmission grating is further provided with a beam-raising mirror on the side away from the plano-convex cylindrical mirror.

[0005] Furthermore, The mode-locked seed source is configured to provide a stable pulse sequence. The output laser wavelength is 1025nm~1035nm, the pulse width is 2ps, the spectral bandwidth is 16nm~25nm, and the repetition frequency is 40MHz.

[0006] Furthermore, The stretcher is configured to perform temporal stretching of the optical pulses output from the mode-locked seed source.

[0007] Furthermore, The timing adjustment module is configured to reduce the frequency of the light output from the mode-locked seed source.

[0008] Furthermore, The fiber amplifier is configured to amplify the down-frequency optical pulses, increase the single-pulse energy, and improve the peak power of the optical pulses.

[0009] Furthermore, The concave surface of the plano-concave cylindrical mirror and the convex surface of the plano-convex cylindrical mirror are both located on the side closest to the first transmission grating.

[0010] Furthermore, The beam-raising mirror is configured to elevate the input light in space and reflect it back to the second transmission grating; The light beam returns to the first transmission grating after passing through the plano-convex cylindrical mirror and the plano-concave cylindrical mirror, and then exits above the reflector.

[0011] The advantages and positive effects of this application are: This technical solution involves placing a plano-concave cylindrical mirror and a plano-convex cylindrical mirror between the first and second transmission gratings, respectively. The plano-concave cylindrical mirror can accurately expand the laser beam emitted from the first transmission grating within a short distance, while the plano-convex cylindrical mirror can simultaneously and efficiently collimate the expanded laser beam. The combination of the two can effectively reduce the optical path, expand the optical path divergence angle, and reduce the diffraction light divergence path, thereby achieving the miniaturization of the femtosecond laser. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the femtosecond laser pulse compression device for shortening optical path provided in the embodiments of this application; Figure 2 A schematic diagram of the beam lifting mirror of the shortened optical path femtosecond laser pulse compression device provided in the embodiments of this application.

[0013] The text labels in the figure represent: 100-mode-locked seed source; 200-broadener; 300-timing adjustment module; 400-fiber amplifier; 500-first transmission grating; 600-second transmission grating; 700-mirror; 800-plano-concave cylindrical mirror; 810-plano-convex cylindrical mirror; 900-beam lifting mirror. Detailed Implementation

[0014] To enable those skilled in the art to better understand the technical solution of this application, the application will be described in detail below with reference to the accompanying drawings. The description in this section is only exemplary and explanatory, and should not be used to limit the scope of protection of this application.

[0015] Please refer to Figures 1-2 This embodiment provides a femtosecond laser pulse compression device for shortening optical path, including a mode-locked seed source 100, a stretcher 200, a timing adjustment module 300, and an fiber amplifier 400 arranged sequentially along the optical path; the pulse compression module includes a first transmission grating 500 and a second transmission grating 600 that are parallel to each other; a reflector 700 is also provided between the first transmission grating 500 and the fiber amplifier 400 to change the direction of the optical path and thus compress the volume; the second transmission grating 600 and the fiber amplifier 400 are... A plano-concave cylindrical mirror 800 and a plano-convex cylindrical mirror 810 are respectively provided between the first transmission grating 500; the plano-concave cylindrical mirror 800 is relatively close to the first transmission grating 500 and is used to expand the laser beam incident through the first transmission grating 500; the plano-convex cylindrical mirror 810 is located between the plano-concave cylindrical mirror 800 and the second transmission grating 600 and is used to collimate the expanded laser beam; a beam lifting mirror 900 is also provided on the side of the second transmission grating 600 away from the plano-convex cylindrical mirror 810.

[0016] In this embodiment, the mode-locked seed source 100 provides a stable pulse sequence which is broadened by the stretcher 200, then down-frequencyd by the timing adjustment module 300 and further amplified by the fiber amplifier 400. After being output, it is reflected by the reflector 700 into the first transmission grating 500. After passing through the first transmission grating 500, the light is diffracted and then expanded by the plano-concave cylindrical mirror 800 and the plano-convex cylindrical mirror 810. After being diffracted by the second transmission grating 600, it becomes a strip-shaped light spot. The beam lifting mirror 900 elevates the input light in space and reflects it back to the second transmission grating 600. The beam returns to the first transmission grating 500 along the original path and exits from above the reflector 700, thus completing the compression process of the pulse time domain width.

[0017] In a preferred embodiment, the mode-locked seed source 100 is configured to provide a stable pulse sequence, with an output laser wavelength of 1025nm to 1035nm, a pulse width of 2ps, a spectral bandwidth of 16nm to 25nm, and a repetition frequency of 40MHz.

[0018] In this embodiment, the output laser wavelength of the mode-locked seed source 100 is 1030nm and the spectral bandwidth is 18nm.

[0019] In a preferred embodiment, the stretcher 200 is configured to perform temporal stretching of the optical pulses output by the mode-locked seed source 100.

[0020] In this embodiment, the time-domain stretching of the stretcher 200 is 19 ps. 2 .

[0021] In a preferred embodiment, the timing adjustment module 300 is configured to reduce the frequency of the light output by the mode-locked seed source 100.

[0022] In this embodiment, the timing adjustment module 300 can effectively reduce the frequency to 1MHz.

[0023] In a preferred embodiment, the fiber amplifier 400 is configured to amplify the down-frequency optical pulse, increase the single pulse energy, and improve the peak power of the optical pulse.

[0024] In this embodiment, the fiber optic amplifier 400 has an amplification power of 10W.

[0025] In a preferred embodiment, the concave surface of the plano-concave cylindrical mirror 800 and the convex surface of the plano-convex cylindrical mirror 810 are both located on the side close to the first transmission grating 500.

[0026] In this embodiment, the focal length of the plano-concave cylindrical mirror 800 is -50mm; the focal length of the plano-convex cylindrical mirror 810 is 100mm; the first transmission grating 500 and the second transmission grating 600 are both selected as 1000 lines / mm; the light spot size incident on the first transmission grating 500 is 1mm; in the compressed optical path, the distance between the plano-concave cylindrical mirror 800 and the first transmission grating 500 is 50mm. From the optical path analysis, it can be seen that the optical path distance is shortened by 8mm, which effectively reduces the optical path volume.

[0027] In a preferred embodiment, the beam-raising mirror 900 is configured to elevate the input light in space and reflect it back to the second transmission grating 600; after the beam passes through the plano-convex cylindrical mirror 810 and the plano-concave cylindrical mirror 800 and returns to the first transmission grating 500, it exits above the reflector 700.

[0028] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of textual expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A device for compressing an optical path femtosecond laser pulse, characterized in that, include The mode-locked seed source (100), stretcher (200), timing adjustment module (300) and fiber amplifier (400) are arranged sequentially along the optical path. A pulse compression module, comprising a first transmission grating (500) and a second transmission grating (600) that are parallel to each other. A reflector (700) is also provided between the first transmission grating (500) and the fiber amplifier (400) to change the direction of the optical path and thus compress the volume; A plano-concave cylindrical mirror (800) and a plano-convex cylindrical mirror (810) are respectively provided between the second transmission grating (600) and the first transmission grating (500). The plano-concave cylindrical mirror (800) is relatively close to the first transmission grating (500) and is used to expand the laser beam incident through the first transmission grating (500). The plano-convex cylindrical mirror (810) is located between the plano-concave cylindrical mirror (800) and the second transmission grating (600) and is used to collimate the expanded laser beam; The second transmission grating (600) is further provided with a beam lifting mirror (900) on the side away from the plano-convex cylindrical mirror (810).

2. The shortened optical path femtosecond laser pulse compression device according to claim 1, characterized in that, The mode-locked seed source (100) is configured to provide a stable pulse sequence. The output laser wavelength is 1025nm~1035nm, the pulse width is 2ps, the spectral bandwidth is 16nm~25nm, and the repetition frequency is 40MHz.

3. The shortened optical path femtosecond laser pulse compression device according to claim 1, characterized in that, The stretcher (200) is configured to perform temporal stretching of the optical pulses output by the mode-locked seed source (100).

4. The shortened optical path femtosecond laser pulse compression device according to claim 1, characterized in that, The timing adjustment module (300) is configured to reduce the frequency of the light output from the mode-locked seed source (100).

5. The shortened optical path femtosecond laser pulse compression device according to claim 1, characterized in that, The fiber amplifier (400) is configured to amplify the down-frequency optical pulse, increase the single pulse energy, and improve the peak power of the optical pulse.

6. The shortened optical path femtosecond laser pulse compression device according to claim 1, characterized in that, The concave surface of the plano-concave cylindrical mirror (800) and the convex surface of the plano-convex cylindrical mirror (810) are both located on the side close to the first transmission grating (500).

7. The shortened optical path femtosecond laser pulse compression device according to claim 1, characterized in that, The beam-raising mirror (900) is configured to elevate the input light in space and reflect it back to the second transmission grating (600). The light beam returns to the first transmission grating (500) after passing through the plano-convex cylindrical mirror (810) and the plano-concave cylindrical mirror (800), and then exits above the reflector (700).

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