A nonlinear compression device based on femtosecond laser pulses

Abstract

The present application discloses a nonlinear compression device based on femtosecond laser pulses, which relates to the field of laser processing technology. The device comprises: a transmitting module, an adjustment module and a pulse compression module arranged in sequence from front to back along the laser incident direction; the transmitting module is used to transmit a first laser pulse; the adjustment module comprises: a nonlinear crystal and a first optical adjustment unit that cooperate with each other; the nonlinear crystal is used to receive the first laser pulse; the optical adjustment unit is used to increase the nonlinear change amount of the first laser pulse at the nonlinear crystal to increase its spectrum broadening amount; the pulse compression module is arranged on the side of the nonlinear crystal away from the transmitting module, and the pulse compression module is used to receive the first laser pulse adjusted by the nonlinear crystal and compress the first laser pulse. The device can effectively solve the problem that the adjustment of the nonlinear broadening amount is complicated and the spot shape cannot be adjusted in nonlinear compression.

Description

Technical Field

[0001] The present disclosure generally relates to the field of laser processing technology, and more particularly to a nonlinear compression device based on femtosecond laser pulses. Background Art

[0002] In femtosecond lasers, chirped pulse amplification (CPA) technology is usually used to generate femtosecond lasers. However, during the use of CPA technology, the pulse width is usually several hundred femtoseconds due to gain narrowing, strong nonlinearity, etc. For example: in the fiber amplification solution, since the fiber itself can support a wider spectrum, although there is a gain narrowing phenomenon, it can still be compressed to 200fs-300fs in the end. However, in the solid solution, since Yb:YAG crystals are usually used for amplification, the crystal emission spectrum of YAG is relatively narrow, so the compressed pulse width is generally 500-800fs. Therefore, if a narrower pulse width is required, a nonlinear compression device needs to be used to further compress the pulse width.

[0003] Traditional nonlinear compression includes two parts: nonlinear spectral broadening and chirped mirror compression. Nonlinear spectral broadening is usually produced by hollow optical fiber, quartz plate, high-pressure gas, etc. The width of the nonlinear spectrum is adjusted by adjusting the length of the optical fiber, the thickness of the quartz plate or the pressure of the high-pressure gas, so that the pulse width after compression can be narrower. However, such a broadening adjustment method is not convenient in implementation. For this reason, we propose a nonlinear compression device based on femtosecond laser pulses. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a nonlinear compression device based on femtosecond laser pulses.

[0005] The present application provides a nonlinear compression device based on femtosecond laser pulses, the device comprising: a transmitting module, an adjustment module and a pulse compression module arranged in sequence from front to back along the incident direction of the laser;

[0006] The transmitting module is used to transmit a first laser pulse;

[0007] The adjustment module comprises: a nonlinear crystal and a first optical adjustment unit that cooperate with each other; the nonlinear crystal is used to receive the first laser pulse; the optical adjustment unit is used to increase the nonlinear change amount of the first laser pulse at the nonlinear crystal to increase its spectrum broadening amount;

[0008] The pulse compression module is disposed on a side of the nonlinear crystal away from the transmitting module, and is used for receiving the first laser pulse adjusted by the nonlinear crystal and compressing the first laser pulse.

[0009] According to the technical solution provided by this application, the first optical adjustment unit includes:

[0010] A radiation laser emitter, wherein the radiation laser emitter is used to emit radiation laser to the nonlinear crystal to increase the refractive index change of the nonlinear crystal;

[0011] Wherein, the radiation laser emitter is arranged on a side of the nonlinear crystal close to the emission module.

[0012] According to the technical solution provided by this application, the first optical adjustment unit also includes:

[0013] An aperture, the aperture being disposed between the radiation laser emitter and the nonlinear crystal;

[0014] The radiation laser emitted by the radiation laser emitter passes through the aperture and is emitted to a surface of the nonlinear crystal close to the emission module.

[0015] According to the technical solution provided in the present application, the adjustment module also includes: a second optical adjustment unit cooperating with the first optical adjustment unit; the second optical adjustment unit is arranged on a side of the nonlinear crystal close to the pulse compression module and avoids the pulse compression module; the second optical adjustment unit is used to reduce the refractive index of the nonlinear crystal.

[0016] According to the technical solution provided in this application, the second optical adjustment unit includes:

[0017] An ultraviolet lamp is used to emit ultraviolet light to the nonlinear crystal, and the ultraviolet light irradiates the surface of the nonlinear crystal on a side away from the transmitting module.

[0018] According to the technical solution provided in the present application, the irradiation area of ​​the ultraviolet light on the corresponding surface of the nonlinear crystal covers the light refraction area of ​​the radiation laser emitter on the corresponding surface of the nonlinear crystal through the aperture.

[0019] According to the technical solution provided in the present application, the pulse compression module includes: a first chirped mirror and a second chirped mirror arranged in sequence along the reflection light path; the first chirped mirror and the second chirped mirror are used to perform negative dispersion compensation on the first laser pulse adjusted by the nonlinear crystal;

[0020] The first chirped mirror is disposed on a side of the nonlinear crystal away from the transmitting module; the first chirped mirror is used to receive the first laser pulse adjusted by the nonlinear crystal;

[0021] The second chirped mirror is used to receive the first laser pulse reflected by the first chirped mirror and adjusted by the nonlinear crystal; when the pulse compression module completes the compression of the adjusted first laser pulse, the second chirped mirror outputs it.

[0022] According to the technical solution provided in the present application, the transmitting module includes: a femtosecond laser light source, and the femtosecond laser light source is used to output the first laser pulse to the nonlinear crystal.

[0023] In summary, the present technical solution specifically discloses a nonlinear compression device based on femtosecond laser pulses, the device comprising: a transmitting module, an adjustment module and a pulse compression module arranged in sequence from front to back along the laser incident direction; the transmitting module is used to transmit a first laser pulse; the adjustment module comprises: a nonlinear crystal and a first optical adjustment unit that cooperate with each other; the nonlinear crystal is used to receive the first laser pulse; the optical adjustment unit is used to increase the nonlinear change amount of the first laser pulse at the nonlinear crystal to increase its spectral broadening amount; the pulse compression module is arranged on a side of the nonlinear crystal away from the transmitting module, the pulse compression module is used to receive the first laser pulse adjusted by the nonlinear crystal, and compress the first laser pulse.

[0024] In view of the problem that the means for adjusting the broadening amount of traditional nonlinear compression is not convenient during implementation, the present invention proposes a nonlinear compression device based on femtosecond laser pulses. The device can transmit the components of a first laser pulse through a transmitting module, and at the same time, the first laser pulse is transmitted to an adjustment module 2, and the spectrum of the first laser pulse is broadened by using a nonlinear crystal and a first optical adjustment unit, so that after the first laser pulse is incident on the pulse compression module, a laser pulse with a narrower pulse width can be finally output. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0026] Figure 1 Schematic diagram of the structure of a nonlinear compression device based on femtosecond laser pulses.

[0027] Figure 2 Schematic diagram of the structure of the first aperture in a nonlinear compression device based on femtosecond laser pulses.

[0028] Figure 3 Schematic diagram of the structure of the second aperture in a nonlinear compression device based on femtosecond laser pulses.

[0029] Numbers in the figure: 1. Transmitting module; 2. Adjusting module; 21. Nonlinear crystal; 22. Radiation laser emitter; 23. Aperture; 24. Ultraviolet lamp; 3. Pulse compression module; 31. First chirped mirror; 32. Second chirped mirror. DETAILED DESCRIPTION

[0030] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] Example 1

[0033] In femtosecond lasers, if a narrower pulse width is required, a nonlinear compression device is often used to further compress the pulse width. In the field of laser physics, pulse post-compression technology is mainly used to increase the peak power of laser pulses and shorten the pulse duration to produce ultrashort laser pulses. This technology is widely used in material processing, medical equipment, communications and other fields.

[0034] In order to overcome the problem that the means for adjusting the amount of broadening in the prior art are not convenient in implementation, the embodiment of the present application aims to propose a nonlinear compression device based on femtosecond laser pulses, which adjusts the refractive index of the nonlinear crystal by combining radiation laser irradiation with ultraviolet light scrubbing to change the amount of nonlinear spectral broadening, thereby adjusting the pulse width, and at the same time obtains an adapted photorefractive area by changing the shape of the aperture to adjust the shape of the transmission light spot, thereby effectively solving the problem that the adjustment of the nonlinear broadening amount is complicated and the spot shape cannot be adjusted in nonlinear compression.

[0035] Please refer to Figure 1 The structure diagram of a nonlinear compression device based on femtosecond laser pulses provided in this embodiment is shown, and the device comprises: a transmitting module 1, an adjustment module 2 and a pulse compression module 3 arranged in sequence from front to back along the laser incident direction;

[0036] The transmitting module 1 is used to transmit a first laser pulse;

[0037] The adjustment module 2 includes: a nonlinear crystal 21 and a first optical adjustment unit that cooperate with each other; the nonlinear crystal 21 is used to receive the first laser pulse; the optical adjustment unit is used to increase the nonlinear change amount of the first laser pulse at the nonlinear crystal 21 to increase its spectrum broadening amount;

[0038] The pulse compression module 3 is disposed on a side of the nonlinear crystal 21 away from the transmitting module 1 . The pulse compression module 3 is used to receive the first laser pulse adjusted by the nonlinear crystal 21 and compress the first laser pulse.

[0039] In the embodiment of the present application, the transmitting module 1 is a component for generating a first laser pulse. When it transmits the first laser pulse to the adjusting module 2, it generates self-phase modulation (SPM) with the nonlinear crystal 21, thereby broadening the spectrum of the first laser pulse.

[0040] In a preferred embodiment, see Figure 1 The transmitting module 1 includes: a femtosecond laser light source, which is used to output a first laser pulse to the nonlinear crystal 21; in actual use, the femtosecond laser light source can output a stable sequence of femtosecond pulse lasers, and the pulse width is generally 300fs-500fs, and there is no specific limitation.

[0041] At the same time, according to Fourier transform, a wider spectrum can support a narrower pulse width in the subsequent process, so changing the spectrum width can adjust the pulse width of the final output laser. Therefore, the refractive index of the nonlinear crystal 21 is changed through the optical adjustment unit to increase the nonlinear change of the first laser pulse to increase its spectrum broadening. Finally, the first laser pulse with a broadened spectrum is input into the pulse compression module 3 for compression to obtain a laser pulse that meets the pulse width requirement.

[0042] Among them, the SPM effect refers to the fact that when a strong laser pulse propagates in a nonlinear medium, due to the nonlinear refractive index of the medium, the optical path of the leading and trailing edges of the pulse is different, resulting in a change in the phase between different parts of the pulse. At the same time, this phase modulation will cause the spectrum to be broadened.

[0043] In a preferred embodiment, see Figure 1 , the first optical adjustment unit includes:

[0044] A radiation laser emitter 22, the radiation laser emitter 22 is used to emit radiation laser to the nonlinear crystal 21 to increase the refractive index change of the nonlinear crystal 21;

[0045] The radiation laser emitter 22 is disposed on a side of the nonlinear crystal 21 close to the emission module 1 .

[0046] See also Figure 1There is no special limitation on the arrangement of the radiation laser emitter 22. It is necessary to ensure that the radiation laser emitted by the radiation laser emitter 22 can be incident on the surface of the nonlinear crystal 2 close to the transmitting module 1, and at the same time, the refraction area formed by the radiation laser emitter 22 in the nonlinear crystal 2 must also be provided for the first emitted laser pulse to pass through.

[0047] In actual application, the magnitude of the refractive index change is determined by controlling the irradiation time of the radiation laser emitter 22 on the nonlinear crystal 2. The longer the irradiation time, the greater the corresponding refractive index change. The greater the nonlinear change of the first laser pulse after passing through the nonlinear crystal 2, the greater the final spectral broadening.

[0048] It should be explained that the nonlinear crystal 21 can be an orthorhombic crystal material such as lithium triborate and other nonlinear crystal materials that can produce nonlinearity; and the radiation laser emitter 22 can select lasers of corresponding bands according to different materials, mainly based on the absorption characteristics of the material, and there is no specific limitation.

[0049] In a preferred embodiment, see Figure 1-Figure 3 , the first optical adjustment unit also includes:

[0050] The aperture 23 is disposed between the radiation laser emitter 22 and the nonlinear crystal 21; wherein the aperture 23 can have different shapes, for example Figure 2 and Figure 3 The triangle and ellipse shown are not particularly limited.

[0051] The radiation laser emitted by the radiation laser emitter 22 is emitted through the aperture 23 to the surface of the nonlinear crystal 21 close to the emission module 1 .

[0052] The first optical adjustment unit is used to adjust the spot shape. Since the radiation laser emitted by the radiation laser emitter 22 passes through the aperture 23, photorefractive regions of different shapes will be formed on the surface of the nonlinear crystal 2 based on the shape of the aperture 23, thereby changing the spot shape of the first laser pulse at the nonlinear crystal 2. Accordingly, different aperture shapes can obtain first laser pulses with different spot shapes.

[0053] In a preferred embodiment, see Figure 1 The adjustment module 2 also includes: a second optical adjustment part that cooperates with the first optical adjustment part; the second optical adjustment part is arranged on a side of the nonlinear crystal 21 close to the pulse compression module 3 and avoids the pulse compression module 3; the second optical adjustment part is used to reduce the refractive index of the nonlinear crystal 21.

[0054] The second optical adjustment part is used to "scrub" the refractive index of the photorefractive region of the nonlinear crystal 2, thereby reducing the refractive index increased by the irradiation laser, so as to achieve adjustable refractive index of the nonlinear crystal 2. It should be explained that the photorefractive region here refers to the region on the nonlinear crystal 21 where the refractive index increases due to the irradiation of the laser. In addition, see Figure 1 It can be seen that the first optical adjustment part and the second adjustment part are both arranged beside the nonlinear crystal 21 to adjust the refractive index of the nonlinear crystal 21 . Therefore, the first optical adjustment part and the second adjustment part.

[0055] In a preferred embodiment, see Figure 1 , the second optical adjustment unit includes:

[0056] The ultraviolet lamp 24 is used to emit ultraviolet light to the nonlinear crystal 21 , and the ultraviolet light irradiates the surface of the nonlinear crystal 21 away from the transmitting module 1 .

[0057] The ultraviolet light emitted by the ultraviolet lamp 24 can change the refractive index of the material through the electro-optical effect. This is because the electrons in the crystal may be excited to a higher energy level, causing the polarization state of the electron cloud to change, thereby reducing the refractive index of the crystal, and then "scrub" the refractive index of the photorefractive region at the nonlinear crystal 21.

[0058] In a preferred embodiment, see Figure 1 The irradiation area of ​​the ultraviolet light on the corresponding surface of the nonlinear crystal 21 covers the light refraction area of ​​the radiated laser emitter 22 on the corresponding surface of the nonlinear crystal 21 through the aperture 23.

[0059] In order to ensure that the ultraviolet light fully "scrubs" the photorefractive area, it is necessary to ensure that the photorefractive area presented by the radiated laser through the aperture 23 on the corresponding surface of the nonlinear crystal 21 can fully fall within the irradiation range of the ultraviolet light on the corresponding surface of the nonlinear crystal 21.

[0060] It should be explained that the duration of ultraviolet light and radiation laser irradiation on the nonlinear crystal 21 and the change in refractive index caused by the specified duration can be calibrated by technicians in the early stage, and the selection of materials for the nonlinear crystal 2 also needs to take into account the factor of performance changes of different materials under ultraviolet light and radiation laser.

[0061] In a preferred embodiment, see Figure 1 The pulse compression module 3 includes: a first chirped mirror 31 and a second chirped mirror 32 arranged in sequence along the reflection light path; the first chirped mirror 31 and the second chirped mirror 32 are used to perform negative dispersion compensation on the first laser pulse adjusted by the nonlinear crystal 21;

[0062] The first chirped mirror 31 is disposed on a side of the nonlinear crystal 21 away from the transmitting module 1; the first chirped mirror 31 is used to receive the first laser pulse adjusted by the nonlinear crystal 21;

[0063] The second chirped mirror 32 is used to receive the first laser pulse reflected by the first chirped mirror 31 and adjusted by the nonlinear crystal 21 ; when the pulse compression module 3 completes the compression of the adjusted first laser pulse, the second chirped mirror 32 outputs it.

[0064] The surface of the chirped mirror has a variable reflection phase to compensate for the dispersion of the light pulse during propagation. In fact, the first chirped mirror 31 and the second chirped mirror 32 are used to reversely compensate for the pulse broadening of the first laser pulse caused by the dispersion effect during propagation, and reverse dispersion is introduced to compensate for the pulse broadening of the laser pulse caused by the dispersion effect during propagation, thereby compressing it.

[0065] Furthermore, after the femtosecond laser is nonlinearly broadened, it is compressed by the pulse compression module 3. Each reflection of the pulse compression module 3 can perform negative dispersion compensation. In actual application, the dispersion amount is usually -500 femtoseconds to -2000 femtoseconds. Different reflection times can compensate for different dispersion amounts. In the embodiment of the present application, see Figure 1 A total of four reflections are performed between the first chirped mirror 31 and the second chirped mirror 32 to adapt the size of the nonlinear broadening amount.

[0066] It needs to be explained that there is no difference between the first chirped mirror and the second chirped mirror in essence. They are distinguished here for the convenience of introduction. In actual situations, the chirped mirror compensation amount and the number of reflections can be selected according to actual conditions. No specific limitations are made here.

[0067] Based on the above description, the present application proposes a nonlinear compression device based on femtosecond laser pulses, the device comprising: a transmitting module 1, an adjustment module 2 and a pulse compression module 3 in sequence from front to back along the laser incident direction; the transmitting module 1 is used to transmit a first laser pulse; the adjustment module 2 comprises: a nonlinear crystal 21 and a first optical adjustment part that cooperate with each other; the nonlinear crystal 21 is used to receive the first laser pulse; the optical adjustment part is used to increase the nonlinear change amount of the first laser pulse at the nonlinear crystal 21 to increase its spectral broadening amount; the pulse compression module 3 is arranged on a side of the nonlinear crystal 21 away from the transmitting module 1, and the pulse compression module 3 is used to receive the first laser pulse adjusted by the nonlinear crystal 21, and compress the first laser pulse.

[0068] The specific working principle of the device is as follows: first, the transmitting module 1, the nonlinear crystal 21, the radiation laser emitter 22, the aperture 23, the ultraviolet lamp 24, the first chirped mirror 31 and the second chirped mirror 32 are arranged according to the designed optical path. Here, it should be noted that the aperture 23 of a suitable shape is selected according to the needs (here, the triangular aperture is taken as an example), and the radiation laser emitter 22 is controlled to be turned on, and the radiation laser is emitted to the nonlinear crystal 21 through the aperture 23 for a certain period of time. Then, the femtosecond laser light source in the transmitting module 1 is controlled to be turned on, and the first laser pulse is emitted to the nonlinear crystal 21 in the adjustment module 2 coordinated therewith. When the first laser pulse is spectrally broadened at the nonlinear crystal 21, it is emitted to the first chirped mirror 31, and at the same time, it is reflected multiple times between the first chirped mirror 31 and the second chirped mirror 32, thereby compensating for the corresponding dispersion amount, and finally completing the compression of the first laser pulse.

[0069] Next, when other nonlinear compression tasks are required, for example, a change in the spot shape is required, the ultraviolet lamp 24 needs to be turned on and ultraviolet light needs to be emitted to the nonlinear crystal 21 to reduce the refractive index in the triangular refractive area originally formed on the nonlinear crystal 21 in order to perform other tasks.

[0070] Example 2

[0071] Based on the device described in Example 1, Example 2 of the present application illustrates the irradiation change of the nonlinear crystal 2 when the aperture 23 is a triangle.

[0072] like Figure 1 and Figure 2 As shown, the femtosecond laser light source outputs a stable sequence of femtosecond pulse lasers. At this time, the femtosecond pulse laser is equivalent to the aforementioned first laser pulse, and the pulse width is 300fs. The spectrum of the laser is broadened after passing through the nonlinear crystal 21, wherein the irradiation time of the radiation laser 22 on the nonlinear crystal 21 is adjusted to determine the magnitude of the nonlinear change. For example, the irradiation time used in this embodiment is 5 minutes, and the aperture 23 added between the radiation laser 22 and the nonlinear crystal 21 is triangular in shape, so the refraction area formed by irradiating the nonlinear crystal is a triangle. When the femtosecond laser passes through the nonlinear crystal, not only the nonlinear spectrum is broadened, but also the spot shape is changed into a triangle. Then, after being reflected between the first chirped mirror 31 and the second chirped mirror 32, the laser pulse width finally output by the second chirped mirror 32 is 100fs.

[0073] Example 3

[0074] Based on the device described in Example 1, Example 3 of the present application describes the irradiation change of the nonlinear crystal 21 when the aperture 23 is elliptical.

[0075] like Figure 1 and Figure 3 As shown, the femtosecond laser light source outputs a stable sequence of femtosecond pulse lasers. At this time, the femtosecond pulse laser is equivalent to the aforementioned first laser pulse, and the pulse width is 500fs. After the laser passes through the nonlinear crystal 21, the spectrum is broadened. Adjusting the irradiation time of the radiation laser 22 on the nonlinear crystal 21 determines the magnitude of the nonlinear change. For example, the irradiation time used in this embodiment is 10min. The aperture 23 added between the radiation laser 22 and the nonlinear crystal 21 is elliptical, and the refractive area formed by irradiating the nonlinear crystal 21 is elliptical. When the femtosecond laser passes through the nonlinear crystal 21, not only the nonlinear increase spectrum is broadened, but also the spot morphology is changed to an ellipse. After further adding a chirped mirror, the output pulse width is 200fs.

[0076] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A nonlinear compression device based on femtosecond laser pulses, characterized in that: The device comprises: a transmitting module (1), an adjusting module (2) and a pulse compression module (3) which are arranged in sequence from front to back along the incident direction of the laser; The transmitting module (1) is used to transmit a first laser pulse; The adjustment module (2) comprises: a nonlinear crystal (21) and a first optical adjustment unit that cooperate with each other; the nonlinear crystal (21) is used to receive the first laser pulse; the optical adjustment unit is used to increase the nonlinear change amount of the first laser pulse at the nonlinear crystal (21) to increase its spectral broadening amount; The pulse compression module (3) is arranged on a side of the nonlinear crystal (21) away from the transmitting module (1), and the pulse compression module (3) is used to receive the first laser pulse adjusted by the nonlinear crystal (21) and compress the first laser pulse; The first optical adjustment unit comprises: a radiation laser emitter (22), the radiation laser emitter (22) being used to emit radiation laser to the nonlinear crystal (21) so as to increase the refractive index variation of the nonlinear crystal (21); Wherein, the radiation laser emitter (22) is arranged on a side of the nonlinear crystal (21) close to the emission module (1); The adjustment module (2) further comprises: a second optical adjustment part cooperating with the first optical adjustment part; the second optical adjustment part is arranged on a side of the nonlinear crystal (21) close to the pulse compression module (3) and avoids the pulse compression module (3); the second optical adjustment part is used to reduce the refractive index of the nonlinear crystal (21); the second optical adjustment part comprises: an ultraviolet lamp (24), the ultraviolet lamp (24) is used to emit ultraviolet light to the nonlinear crystal (21), the ultraviolet light irradiating the surface of the nonlinear crystal (21) on a side away from the emission module (1).

2. A nonlinear compression device based on femtosecond laser pulses according to claim 1, characterized in that: The first optical adjustment unit further includes: An aperture (23), the aperture (23) being arranged between the radiation laser emitter (22) and the nonlinear crystal (21); The radiation laser emitted by the radiation laser emitter (22) is emitted through the aperture (23) to the surface of the nonlinear crystal (21) on a side close to the emission module (1).

3. The nonlinear compression device based on femtosecond laser pulses according to claim 2, characterized in that: The irradiation area of ​​the ultraviolet light on the corresponding surface of the nonlinear crystal (21) covers the light refraction area of ​​the radiation laser emitter (22) on the corresponding surface of the nonlinear crystal (21) through the aperture (23).

4. The nonlinear compression device based on femtosecond laser pulses according to claim 1, characterized in that: The pulse compression module (3) comprises: a first chirped mirror (31) and a second chirped mirror (32) arranged in sequence along a reflection light path; the first chirped mirror (31) and the second chirped mirror (32) are used to perform negative dispersion compensation on the first laser pulse adjusted by the nonlinear crystal (21); The first chirped mirror (31) is arranged on a side of the nonlinear crystal (21) away from the transmitting module (1); the first chirped mirror (31) is used to receive the first laser pulse adjusted by the nonlinear crystal (21); The second chirped mirror (32) is used to receive the first laser pulse reflected by the first chirped mirror (31) and adjusted by the nonlinear crystal (21); when the pulse compression module (3) completes compression of the adjusted first laser pulse, the second chirped mirror (32) outputs it.

5. The nonlinear compression device based on femtosecond laser pulses according to claim 1, characterized in that: The transmitting module (1) comprises: a femtosecond laser light source, which is used to output the first laser pulse to the nonlinear crystal (21).

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