Visible light fiber gas Raman laser

Abstract

The present invention provides a visible light fiber gas Raman laser, which includes a 1μm pump source and a hollow core fiber. The 1μm pump source outputs pump laser with a wavelength range of 950nm - 1080nm; the pump laser is coupled into the core of the hollow core fiber sealed at both ends; hydrogen gas is filled in the core of the hollow core fiber; the pump laser undergoes stimulated Raman scattering and four-wave mixing effects with hydrogen gas in the hollow core fiber to generate and output anti-Stokes lasers in the red, green, and blue visible light bands; a visible light band-pass filter, whose central wavelength is the anti-Stokes wavelength of the red, green, or blue visible light band of hydrogen gas, and the visible light band-pass filter filters out the non-target wavelength light beams output by the hollow core fiber and outputs the visible light of the target wavelength. The structure of the present invention is compact and can efficiently output anti-Stokes lasers in the red, green, and blue visible light bands.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of fiber laser, and in particular to a visible light fiber gas Raman laser. Background Art

[0002] The wavelength range of visible light is approximately 400 nm - 780 nm. Lasers in the visible light band have important application values in the fields of display, medical treatment, communication, lighting, sensing, etc., and have attracted extensive attention. From the perspective of technical means for realizing visible light, semiconductor, gas, solid, and fiber lasers can all generate visible light lasers. However, semiconductor lasers have poor beam quality and wide laser linewidths, gas lasers have non-compact structures, and solid lasers have high requirements for environmental stability. Fiber lasers have advantages such as good beam quality, compact structure, and convenient thermal management. However, in the visible light band, fluoride fibers are mainly used, which have certain disadvantages in terms of anti-deliquescence and high power tolerance.

[0003] The fiber gas Raman laser developed with the emergence of hollow-core fibers can be used as an alternative to fiber lasers, providing a means to obtain visible light lasers. A fiber gas Raman laser fills a hollow-core fiber with a Raman gain gas and obtains gas Raman laser output in the hollow-core fiber by means of optical pumping. Gas stimulated Raman scattering has the advantages of high gain coefficient, a wide variety of selectable media, and narrow linewidth, and can achieve narrow-linewidth laser output of the target wavelength within a large wavelength range. The core of the hollow-core fiber can be filled with a gas medium to confine the laser transmission, so it provides an almost ideal environment for the stimulated Raman scattering of the gas, which can greatly increase the interaction distance and interaction intensity between the gas and the laser. At the same time, the transmission band range and dispersion characteristics of the silicon-based hollow-core fiber can be controlled by designing the microstructure of the hollow-core fiber. Existing fiber gas Raman lasers mainly focus on the output of Stokes light, especially the output of the first-order Stokes light. However, there has been no public report in the art on whether it is possible to use an infrared laser pump in an anti-resonant hollow-core fiber to achieve multi-wavelength visible light output of a fiber gas Raman laser based on anti-Stokes light, that is, there are few reports on visible light fiber gas Raman lasers based on anti-Stokes light. Summary of the Invention

[0004] In view of the technical problems existing in the prior art, the present invention proposes a visible light fiber gas Raman laser.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A visible light fiber gas Raman laser, comprising a 1 μm pump source, a hollow-core fiber, and a working gas:

[0007] The 1 μm pump source outputs pump laser with a wavelength range of 950 nm - 1080 nm;

[0008] The pump laser is coupled into the core of a hollow fiber sealed at both ends.

[0009] The core of the hollow fiber is filled with a working gas, and the working gas is hydrogen.

[0010] The pump laser undergoes stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow fiber, generating anti-Stokes lasers in the visible light bands of red, green, and blue and outputting them.

[0011] A visible light bandpass filter, whose central wavelength is the anti-Stokes wavelength of the red, green, or blue visible light band of hydrogen, filters out the beams of non-target wavelengths output from the hollow fiber and outputs visible light of the target wavelength.

[0012] Furthermore, the 1 μm pump source is a 1 μm linearly polarized narrow linewidth high peak power pulsed laser, with a degree of linear polarization greater than 1000:1, a linewidth less than or equal to 0.1 nm, a pulse width less than 3 ns, and a maximum peak power higher than 30 kW.

[0013] Furthermore, it further includes a coupling lens, which has a high transmittance for the pump laser and focuses and couples the pump laser into the core of the hollow fiber.

[0014] Furthermore, both ends of the hollow fiber are sealed by an input end small gas chamber and an output end small gas chamber, and at least one of the input end small gas chamber and the output end small gas chamber is connected to a gas mass flow controller, which is used to evacuate the core of the hollow fiber, fill the core of the hollow fiber with the working gas, and control the gas flow rate of the filled working gas, thereby controlling the air pressure in the input end small gas chamber, the output end small gas chamber, and the core of the hollow fiber.

[0015] Furthermore, the gas mass flow controller is connected to the corresponding small gas chamber using a valve gas pipe, which is used to control the gas flow rate flowing into the small gas chamber and the hollow fiber, thereby precisely controlling the air pressure in the small gas chamber and the hollow fiber. It can withstand a maximum high pressure of 100 bar and can control the minimum inflation step size to be 0.1 bar.

[0016] Furthermore, the 1 μm pump source is a 1064 nm linearly polarized narrow linewidth high peak power pulsed laser, with a degree of linear polarization greater than 1000:1, a linewidth of 0.1 nm, a pulse width of 1 ns, and a maximum peak power higher than 30 kW.

[0017] Further, the output pump laser wavelength of the 1 μm pump source is 1064 nm, and the first, second, and third anti-Stokes wavelengths are 738 nm, 565 nm, and 457 nm respectively, corresponding to red, green, and blue lasers.

[0018] Further, the hollow fiber has low transmission loss for the 1064 nm band of the pump laser wavelength, the 1.9 μm band of the Stokes wavelength, and the visible light band of the anti-Stokes, while having high transmission loss for lasers in other bands.

[0019] Further, it also includes a collimating lens, which is arranged on one side of the output end of the hollow fiber. The collimating lens has a high transmittance for the visible light laser output from the hollow fiber and collimates the visible light laser for output to the visible light bandpass filter.

[0020] Further, the hollow fiber is an anti-resonant hollow fiber, which can transmit visible light and near-infrared band lasers.

[0021] Compared with the prior art, the beneficial technical effects of the present invention include:

[0022] The present invention provides a visible light fiber gas Raman laser, which can obtain visible light fiber laser output with high beam quality, high power, and narrow linewidth.

[0023] The basic principle of the present invention is the stimulated Raman scattering of gas in the hollow fiber. The pump laser undergoes stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow fiber, generating anti-Stokes lasers in the visible light bands of red, green, and blue, making up for the deficiency that it is difficult for silicon-based fiber lasers to achieve visible light output.

[0024] In the present invention, the wavelength range of the pump laser is 950 nm - 1080 nm, the degree of linear polarization is greater than 1000:1, the linewidth is less than or equal to 0.1 nm, the pulse width is less than 3 ns, and the length of the hollow fiber can be several tens of centimeters. The length of the hollow fiber will affect the output efficiency of visible light. The length requirement of the hollow fiber is determined by the pulse width of the pump source used, and the length requirement of the hollow fiber is greater than or equal to the pulse width of the pump laser. The speed of light in vacuum. Traditional gas lasers generally use a metal cavity structure, and the cavity is generally relatively long, on the order of several meters, and the volume is relatively large. The pulse width of the pump laser used in the present invention is less than 3 ns, and the length of the hollow fiber can be several tens of centimeters. In this way, the fiber length and output efficiency can be balanced, and an ultra-short hollow fiber structure can be realized.

[0025] Further, the present invention uses a small gas cavity to seal the hollow fiber, which has the advantages of compact structure, easy to carry, and easy to maintain.

[0026] Furthermore, the present invention adopts a gas mass flow controller to precisely control the air pressure inside the hollow fiber by controlling the flow rates of the gases flowing into the small gas chamber and the hollow fiber, thus compensating for the disadvantage that it is difficult to control the air pressure when high-pressure gases are filled into existing fiber gas lasers.

[0027] Furthermore, the present invention combines the advantages of high output power, high damage threshold of gas lasers and good beam quality of fiber lasers, and has great potential advantages in practical applications. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0029] Figure 1 It is a schematic structural diagram of a visible light fiber gas Raman laser provided by an embodiment;

[0030] Figure 2 It is a schematic diagram of the transmission loss of a hollow fiber provided by an embodiment;

[0031] Figure 3 It is an output spectrum diagram of a visible light fiber gas Raman laser filled with 23 bar H2 provided by an embodiment;

[0032] Figure 4 It is a diagram showing the influence of filling 4 bar - 30 bar H2 into the core of a hollow fiber on the average power of the output 738 nm red laser of a visible light fiber gas Raman laser under a coupled pump laser power of 0 mW - 720 mW provided by an embodiment.

[0033] Legend Explanation:

[0034] 1. 1 μm pump source; 2. Coupling lens; 3. Input gas mass flow controller; 4. Input small gas chamber; 5. Hollow fiber; 6. Output small gas chamber; 7. Output gas mass flow controller; 8. Collimating lens; 9. Visible light band-pass filter. Detailed Embodiments

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] Reference Figure 1 , a visible light fiber gas Raman laser provided by an embodiment has a compact structure, and the length of the hollow fiber can be dozens of centimeters. Specifically, the visible light fiber gas Raman laser includes:

[0037] A 1 μm pump source 1 outputs pump laser with a wavelength range of 950 nm - 1080 nm;

[0038] The pump laser is coupled into the core of the hollow fiber 5 sealed at both ends;

[0039] The core of the hollow fiber 5 is filled with a working gas, and the working gas is hydrogen;

[0040] The pump laser undergoes stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow fiber 5, generating anti-Stokes lasers in the visible light bands of red, green, and blue and outputting them;

[0041] A collimating lens 8 is arranged on one side of the output end of the hollow fiber 5. The collimating lens 8 has a high transmittance for the visible light laser output from the hollow fiber 5 and collimates the visible light laser for output to the visible light bandpass filter 9;

[0042] The visible light bandpass filter 9 has a center wavelength that is the anti-Stokes wavelength of the red, green, or blue visible light band of hydrogen. The visible light bandpass filter filters out the non-target wavelength light beams output from the hollow fiber 5 and outputs the visible light of the target wavelength.

[0043] Preferably, Figure 1 A coupling lens 2 is also provided. The pump laser output from the 1 μm pump source 1 enters the hollow fiber 5 through the coupling lens 2. The coupling lens 2 has a high transmittance for the pump laser and focuses and couples the pump laser into the core of the hollow fiber 5. The hollow fiber 5 can conduct visible light in the near-infrared band and has a length of dozens of centimeters.

[0044] Both ends of the hollow-core optical fiber 5 are sealed by the input-end small gas chamber 4 and the output-end small gas chamber 6. First, use the input-end gas mass flow controller 3 and the output-end gas mass flow controller 7 to evacuate the input-end small gas chamber 4, the output-end small gas chamber 6, and the hollow-core optical fiber 5 to vacuum, and then fill the hollow-core optical fiber 5 with the working gas hydrogen. The charging amount is controlled by the input-end gas mass flow controller 3 and the output-end gas mass flow controller 7, and the minimum charging step can be controlled to 0.1 bar. The pump laser generates anti-Stokes lasers in the visible light bands of red, green, and blue through stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow-core optical fiber 5. It is collimated and output by the collimating lens 8, and then the visible light laser of the target wavelength is obtained by filtering through the visible light band-pass filter 9. If the target wavelength is the anti-Stokes wavelength of the red light wavelength, the selected visible light band-pass filter 9 can filter out the light beams of the remaining wavelengths except the red light wavelength and output the visible light of the target wavelength, that is, red light.

[0045] The 1 μm pump source is a 1 μm narrow linewidth high peak power pulsed laser with a wavelength range of 950 nm - 1080 nm. Preferably, a 1064 nm narrow linewidth high peak power pulsed laser is used, and multi-order anti-Stokes light of red, green, and blue can be generated within this wavelength range. The linewidth of the pump laser output by the 1 μm pump source should be less than 0.1 nm. To excite pure vibrational stimulated Raman scattering, the degree of linear polarization should be greater than 1000:1. To excite transient stimulated Raman scattering in a hollow-core optical fiber with a length of dozens of centimeters (less than 1 meter), the pulse width of the pump laser output by the 1 μm pump source should be less than 3 ns. To reach the stimulated Raman scattering threshold and output efficiently, the peak power is higher than 30 kW.

[0046] The gas mass flow controllers (including the input-end gas mass flow controller 3 and the output-end gas mass flow controller 7) are connected to the corresponding small gas chambers (the input-end small gas chamber 4 and the output-end small gas chamber 6) using valve conduits, and are used to control the gas flow rate flowing into the small gas chambers and the hollow-core optical fiber, thereby precisely controlling the air pressure in the small gas chambers and the hollow-core optical fiber. The maximum pressure it can withstand is 100 bar, and the minimum controllable charging step is 0.1 bar.

[0047] For the input-end small gas chamber 4 and the output-end small gas chamber 6, rubber rings are used for internal sealing, so that the laser output window of the output-end small gas chamber 6 faces the output end of the hollow-core optical fiber. The laser output window of the output-end small gas chamber 6 has high transmittance to visible light. Both the input-end small gas chamber 4 and the output-end small gas chamber 6 are connected with valve conduits, which are used to control the air pressure in the small gas chambers, thereby controlling the air pressure in the hollow-core optical fiber.

[0048] To verify the effectiveness of the present invention, a specific application example is provided below to illustrate the effectiveness of the present invention as follows:

[0049] The visible light fiber gas Raman laser provided in this embodiment is based on Figure 1 the structure shown in the figure, and includes a 1 μm pump source 1, a coupling lens 2, an input gas mass flow controller 3, an input small gas chamber 4, a hollow fiber 5, an output small gas chamber 6, an output gas mass flow controller 7, a collimating lens 8, and a visible light band-pass filter 9.

[0050] The 1 μm pump source 1 is a 1064 nm linearly polarized narrow linewidth high peak power pulsed laser, with a linear polarization degree of 1000:1, a linewidth of 0.1 nm, a pulse width of 1 ns, and a peak power higher than 30 kW.

[0051] The hollow fiber 5 is an anti-resonant hollow fiber, which can transmit visible light and near-infrared band lasers. The working gas filled in the hollow fiber 5 is hydrogen.

[0052] The collimating lens 8 has a high transmittance for visible light lasers and can collimate and output visible light lasers.

[0053] The visible light band-pass filter 9 is a visible light band-pass filter, which is arranged outside the laser output window, and its central wavelength is the anti-Stokes wavelength of hydrogen.

[0054] Other settings such as the input gas mass flow controller 3, the input small gas chamber 4, the output small gas chamber 6, and the output gas mass flow controller 7 can adopt the same settings as those in the previous embodiment, and will not be elaborated here.

[0055] In this embodiment, a 1064 nm narrow linewidth high peak power pulsed laser is used as the 1 μm pump source 1. The pump laser first passes through the coupling lens 2 and is coupled into the hollow fiber 5. The core of the hollow fiber 5 is filled with gas and at the same time restricts the transmission of the pump laser, providing an ideal environment for the interaction between the working gas and the pump laser. The working gas filled inside the hollow fiber 5 is hydrogen. Starting from 0 bar pressure, the pressure is gradually increased in steps of 1 bar until the output power of the red light laser is the highest. By selecting an appropriate pressure and using the stimulated Raman scattering of hydrogen, the pump laser frequency can be up-converted to the visible light band. The generated visible light laser is output from the laser output window of the output small gas chamber 6, collimated by the collimating lens 8 and output to the visible light band-pass filter 9, and the residual pump light and other non-target wavelength lasers are filtered out by the visible light band-pass filter 9 and then output.

[0056] The working gas is hydrogen, which has 4155 cm -1The vibration frequency shift coefficient can shift the pump laser to red, green, and blue lasers through the anti-Stokes process of stimulated Raman scattering.

[0057] The input small gas chamber 4 and the output small gas chamber 6 are sealed with rubber rings inside. The end of the hollow fiber is aligned with the laser output window of the output small gas chamber 6, and the laser output window of the output small gas chamber 6 has high transmittance to visible light. The input small gas chamber 4 and the output small gas chamber 6 are both connected with gas pipes with valves. The other ends of the gas pipes with valves are connected to the corresponding gas mass flow controllers. By controlling the gas flow rates flowing into the input small gas chamber 4, the output small gas chamber 6, and the hollow fiber, an increase in air pressure with a step of 0.1 bar can be achieved, and the air pressure inside the hollow fiber can be accurately controlled.

[0058] At the same time, the selection of the pump laser wavelength determines the specific wavelength of the output visible light laser. The pump laser wavelength, the anti-Stokes wavelength, and the frequency shift coefficient of gas molecules are determined by the following formula:

[0059] ;

[0060] In the formula λ p is the pump laser wavelength, λ as is the anti-Stokes wavelength, and Ω R is the Raman frequency shift coefficient. Since hydrogen (H2) molecules have a vibrational Raman spectral line with a vibrational frequency shift coefficient of 4155 cm -1 , when the pump laser wavelength is 1064 nm, the first, second, and third anti-Stokes wavelengths are 738 nm, 565 nm, and 457 nm respectively, corresponding to red, green, and blue lasers.

[0061] Reference Figure 2 , which is a schematic diagram of the transmission loss of the hollow fiber in this embodiment, has low transmission loss for the 1064 nm band of the pump laser wavelength, the 1.9 μm band of the Stokes wavelength, and the visible light band of the anti-Stokes, while having high transmission loss for lasers in other bands.

[0062] Figure 3 This is the output spectrum diagram of the visible light fiber gas Raman laser provided in this embodiment when filled with 23 bar H2. As can be seen from Figure 3 , when the coupled pump average power is filled with 23 bar H2, red, green, and blue lasers with wavelengths of 457 nm, 565 nm, and 738 nm are simultaneously generated, indicating that the compact visible light fiber gas Raman laser provided by the present invention can operate.

[0063] Figure 4For the visible light fiber gas Raman laser provided in this embodiment, it is a diagram showing the influence of filling 4 bar to 30 bar H2 into the core of the hollow fiber on the average power of the output 738 nm red laser under the coupled pump laser power of 0 mW to 720 mW. The corresponding coupled pump average power threshold for the generation of 738 nm red light is 210 mW. When the coupled pump average power is 720 mW, under the H2 gas pressure of 4 bar to 23 bar, as the gas pressure increases, the average power of the 738 nm red light output increases and reaches the maximum value of 9.71 mW at the gas pressure of 23 bar; under the H2 gas pressure of 23 bar to 30 bar, as the gas pressure increases, the average power of the 738 nm red light output decreases. Since the generation of 565 nm green light and 457 nm blue light is the same as that of 738 nm red light, both are generated by the four-wave mixing effect, so the influence trends of the output laser powers of 565 nm green light and 457 nm blue light with the coupled pump power and gas pressure are the same as those of 738 nm red light, which will not be elaborated here.

[0064] Through the above specific application embodiments and the corresponding data and effect diagrams, the effectiveness of the present invention is fully illustrated.

[0065] Furthermore, by precisely adjusting the gas pressure inside the hollow fiber, the optimal phase matching of the pump wave, the first-order Stokes wave, and the first-order anti-Stokes wave can be achieved. This carefully designed phase matching helps to achieve an efficient four-wave mixing process, thereby generating a large amount of anti-Stokes light with a high conversion efficiency, and further expanding the output wavelength range of the existing fiber gas Raman laser. In addition, the output of the fiber gas Raman laser is not restricted by stimulated Brillouin scattering, and at the same time, it has the advantages of high beam quality and easy maintenance of general fiber lasers.

[0066] Matters not covered in this invention are well-known technologies.

[0067] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0068] The above-described embodiments merely represent several implementation manners of this application. The description is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application should be subject to the appended claims.

[0069] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Visible light fiber gas Raman laser, characterized in that, Including: 1 μm pump source, hollow-core fiber, working gas; 1 μm pump source, which outputs pump laser with a wavelength range of 950 nm - 1080 nm. The 1 μm pump source is a 1 μm linearly polarized narrow linewidth high peak power pulsed laser, with a degree of linear polarization greater than 1000:1, a linewidth less than or equal to 0.1 nm, a pulse width less than 3 ns, and a maximum peak power higher than 30 kW; The pump laser is coupled into the core of the hollow-core fiber sealed at both ends; The core of the hollow-core optical fiber is filled with a working gas, which is hydrogen. The length of the hollow-core optical fiber is required to be greater than or equal to the pulse width of the pump laser the speed of light in vacuum and the length of the hollow-core optical fiber is less than 1 meter; The pump laser undergoes stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow-core fiber to generate anti-Stokes lasers in the red, green, and blue visible light bands and output them; Visible light bandpass filter, whose central wavelength is the anti-Stokes wavelength in the red, green, or blue visible light band of hydrogen. The visible light bandpass filter filters out the non-target wavelength light beams output from the hollow-core fiber and outputs the visible light of the target wavelength.

2. The visible light fiber gas Raman laser according to claim 1, wherein It also includes a coupling lens, which has a high transmittance for the pump laser and focuses and couples the pump laser into the core of the hollow-core fiber.

3. The visible light fiber gas Raman laser according to claim 2, characterized in that, Both ends of the hollow-core fiber are sealed by an input end small gas chamber and an output end small gas chamber. At least one of the input end small gas chamber and the output end small gas chamber is connected to a gas mass flow controller, which is used to evacuate the core of the hollow-core fiber, fill the core of the hollow-core fiber with working gas, and control the gas flow of the filled working gas, thereby controlling the air pressure in the input end small gas chamber, the output end small gas chamber, and the core of the hollow-core fiber.

4. The visible light fiber gas Raman laser according to claim 3, characterized in that The gas mass flow controller is connected to the corresponding small gas chamber using a valve gas pipe, which is used to control the gas flow into the small gas chamber and the hollow-core fiber, thereby precisely controlling the air pressure in the small gas chamber and the hollow-core fiber. It can withstand a maximum high pressure of 100 bar and can control the minimum inflation step size to be 0.1 bar.

5. The visible light fiber gas Raman laser according to claim 3 or 4, characterized in that, The 1 μm pump source is a 1064 nm linearly polarized narrow linewidth high peak power pulsed laser, with a degree of linear polarization greater than 1000:1, a linewidth of 0.1 nm, a pulse width of 1 ns, and a maximum peak power higher than 30 kW.

6. The visible light fiber gas Raman laser according to claim 5, wherein The 1 μm pump source outputs pump laser with a wavelength of 1064 nm. The first, second, and third order anti-Stokes wavelengths are 738 nm, 565 nm, and 457 nm respectively, corresponding to red, green, and blue lasers.

7. The visible light fiber gas Raman laser according to claim 6, wherein The hollow-core fiber has low transmission loss for the 1064 nm band of the pump laser wavelength, the 1.9 μm band of the Stokes wavelength, and the visible light band of the anti-Stokes, while having high transmission loss for lasers in other bands.

8. The visible light fiber gas Raman laser according to claim 1 or 2 or 3 or 4 or 6 or 7, characterized in that It also includes a collimating lens, which is arranged on one side of the output end of the hollow-core fiber. The collimating lens has a high transmittance for the visible light laser output from the hollow-core fiber and collimates and outputs the visible light laser to the visible light bandpass filter.

9. The visible-light fiber gas Raman laser according to claim 8, wherein, The hollow-core fiber is an anti-resonant hollow-core fiber, which can transmit visible light and near-infrared band lasers.

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