Visible light optical fiber gas Raman laser

Abstract

The invention provides a visible light optical fiber gas Raman laser which comprises a 1 [mu] m pumping source and a hollow-core optical fiber, the 1 [mu] m pumping source outputs pumping laser, and the wavelength range is 950 nm to 1080 nm; pumping laser is coupled into a fiber core of the hollow-core optical fiber with two sealed ends; the fiber core of the hollow-core optical fiber is filled with hydrogen; the pumping laser generates stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow-core optical fiber, and anti-Stokes laser in three-color visible light wave bands of red, green and blue is generated and output; and the central wavelength of the visible light band-pass filter is the anti-Stokes wavelength of the red, green or blue visible light wave band of the hydrogen, and the visible light band-pass filter filters out the light beams with the non-target wavelength output by the hollow-core optical fiber and outputs visible light with the target wavelength. The device is compact in structure, and can efficiently output anti-Stokes laser in red, green and blue visible light wavebands.

Description

Technical Field

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

[0002] The wavelength range of visible light is approximately 400nm - 780nm. 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 to achieve 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 uses optical pumping to obtain gas Raman laser output in the hollow-core fiber. 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, thus providing 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 is no public report in this field on whether infrared laser pumping can be used 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: A visible light fiber gas Raman laser, comprising a 1μm pump source, a hollow-core fiber, and a working gas: The 1μm pump source outputs pump laser with a wavelength range of 950nm - 1080nm; The pump laser is coupled into the core of a hollow-core optical fiber sealed at both ends; The core of the hollow core optical fiber is filled with a working gas, which is hydrogen; The pump laser generates stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow-core optical fiber, generating and outputting anti-Stokes lasers in the red, green and blue visible light bands. The visible light bandpass filter 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 light beam of non-target wavelength output by the hollow-core optical fiber and outputs visible light of target wavelength.

[0006] Furthermore, the 1 μm pump source is a 1 μm linearly polarized narrow linewidth high peak power pulse laser, with a linear polarization degree 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.

[0007] Furthermore, it also includes a coupling lens, which has high transmittance to the pump laser and focuses the pump laser to couple it into the core of the hollow-core optical fiber.

[0008] Furthermore, both ends of the hollow-core optical fiber are sealed by a small gas cavity at the input end and a small gas cavity at the output end, and at least one of the small gas cavity at the input end and the small gas cavity at the output end is connected to a gas mass flow controller for evacuating the core of the hollow-core optical fiber, filling the core of the hollow-core optical fiber with working gas and controlling the gas flow of the working gas, thereby controlling the air pressure in the small gas cavity at the input end, the small gas cavity at the output end and the core of the hollow-core optical fiber.

[0009] Furthermore, the gas mass flow controller uses a valved air duct connected to the corresponding small gas cavity to control the gas flow into the small gas cavity and the hollow-core optical fiber, thereby accurately controlling the gas pressure in the small gas cavity and the hollow-core optical fiber. It can withstand a maximum high pressure of 100 bar and can control the inflation step to a minimum of 0.1 bar.

[0010] Furthermore, the 1 μm pump source is a 1064 nm linearly polarized narrow linewidth high peak power pulse laser, with a linear polarization degree greater than 1000:1, a linewidth of 0.1 nm, a pulse width of 1 ns, and a maximum peak power greater than 30 kW.

[0011] Furthermore, the 1 μm pump source outputs a pump laser wavelength of 1064 nm, and 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.

[0012] Furthermore, the hollow-core optical 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 anti-Stokes visible light band, but has high transmission loss for lasers in other bands.

[0013] Furthermore, it also includes a collimating lens, which is arranged on one side of the output end of the hollow-core optical fiber. The collimating lens has a high transmittance to the visible light laser output by the hollow-core optical fiber, and collimates the visible light laser and outputs it to the visible light bandpass filter.

[0014] Furthermore, the hollow-core optical fiber is an anti-resonant hollow-core optical fiber capable of transmitting visible light and near-infrared lasers.

[0015] Compared with the prior art, the beneficial technical effects of the present invention include: The 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 line width.

[0016] The basic principle of the present invention is stimulated Raman scattering of gas in hollow-core optical fiber. The pump laser undergoes stimulated Raman scattering and four-wave mixing effect with hydrogen in the hollow-core optical fiber to generate anti-Stokes lasers in the red, green and blue visible light bands, making up for the deficiency that silicon-based fiber lasers are difficult to achieve visible light output.

[0017] The wavelength range of the pump laser in the present invention is 950nm-1080nm, the linear polarization degree is greater than 1000:1, the line width is less than or equal to 0.1nm, the pulse width is less than 3ns, and the length of the hollow-core fiber can be tens of centimeters. The length of the hollow-core fiber will affect the output efficiency of visible light. The length requirement of the hollow-core fiber is determined by the pulse width of the pump source used. The length requirement of the hollow-core fiber is greater than or equal to (the pulse width of the pump laser The speed of light in vacuum). Conventional gas lasers generally use a metal cavity structure, and the cavity is generally long, on the order of several meters, and has a relatively large volume. The pulse width of the pump laser used in the present invention is less than 3ns, and the length of the hollow-core fiber can be tens of centimeters. This balances the fiber length and output efficiency, and enables the realization of an ultra-short hollow-core fiber structure.

[0018] Furthermore, the present invention uses a small gas cavity to seal the hollow core optical fiber, which has the advantages of compact structure, easy portability and easy maintenance.

[0019] Furthermore, the present invention adopts a gas mass flow controller to accurately control the gas pressure in the hollow-core optical fiber by controlling the flow rate of the gas flowing into the small gas cavity and the hollow-core optical fiber, thereby compensating for the disadvantage that the gas pressure is difficult to control when the existing fiber gas laser is filled with high-pressure gas.

[0020] Furthermore, the present invention combines the advantages of high output power and high damage threshold of gas lasers with the good beam quality of fiber lasers, and has great potential advantages in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0022] Figure 1 is a schematic structural diagram of a visible light fiber gas Raman laser provided by an embodiment; Figure 2 A schematic diagram of transmission loss of a hollow core optical fiber provided by an embodiment; Figure 3 A visible light fiber gas Raman laser provided in an embodiment is filled with 23 bar H 2 Output spectrum of Figure 4 In a visible light fiber gas Raman laser provided in an embodiment, 4 bar to 30 bar H is filled into the hollow core fiber core at a coupled pump laser power of 0 mW to 720 mW. 2 Graph showing the impact on the average power of the output 738nm red laser.

[0023] Legend: 1. 1μm pump source; 2. Coupling lens; 3. Gas mass flow controller at the input end; 4. Small gas cavity at the input end; 5. Hollow core optical fiber; 6. Small gas cavity at the output end; 7. Gas mass flow controller at the output end; 8. Collimating lens; 9. Visible light bandpass filter. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] refer to Figure 1 An embodiment provides a visible light fiber gas Raman laser, which has a compact structure, and the length of the hollow core fiber can be tens of centimeters. Specifically, the visible light fiber gas Raman laser includes: 1μm pump source 1, outputting pump laser with a wavelength range of 950nm-1080nm; The pump laser is coupled into the core of the hollow core optical fiber 5 sealed at both ends; The core of the hollow core optical fiber 5 is filled with a working gas, which is hydrogen; The pump laser generates stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow-core optical fiber 5, generating and outputting anti-Stokes lasers in the red, green and blue visible light bands; The collimating lens 8 is arranged at one side of the output end of the hollow core optical fiber 5. The collimating lens 8 has a high transmittance to the visible light laser outputted by the hollow core optical fiber 5, and collimates the visible light laser and outputs it to the visible light bandpass filter 9; The visible light bandpass filter 9 has a central 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 light beam of non-target wavelength output by the hollow-core optical fiber 5 and outputs visible light of target wavelength.

[0026] Preferably, Figure 1 A coupling lens 2 is also provided in the hollow core fiber 5. The pump laser output by the 1 μm pump source 1 enters the hollow core fiber 5 through the coupling lens 2. The coupling lens 2 has a high transmittance to the pump laser and focuses the pump laser and couples it into the core of the hollow core fiber 5. The hollow core fiber 5 can guide visible light and near-infrared bands and has a length of tens of centimeters.

[0027] The two ends of the hollow-core optical fiber 5 are sealed by a small gas cavity 4 at the input end and a small gas cavity 6 at the output end. First, the small gas cavity 4 at the input end, the small gas cavity 6 at the output end and the hollow-core optical fiber 5 are evacuated to a vacuum by using the gas mass flow controller 3 at the input end and the gas mass flow controller 7 at the output end, and then the working gas hydrogen is filled into the hollow-core optical fiber 5. The filling amount is controlled by the gas mass flow controller 3 at the input end and the gas mass flow controller 7 at the output end, and the minimum filling step can be controlled to be 0.1 bar. The pump laser undergoes stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow-core optical fiber 5, generating anti-Stokes lasers in the red, green and blue visible light bands. The output is collimated by a collimating lens 8, and then filtered by a visible light bandpass filter 9 to obtain a visible light laser of the target wavelength. If the target wavelength is the anti-Stokes wavelength of the red light wavelength, the selected visible light bandpass 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, i.e., red light.

[0028] The 1μm pump source is a 1μm narrow linewidth high peak power pulse laser with a wavelength range of 950nm-1080nm. Preferably, a 1064nm narrow linewidth high peak power pulse laser is used, which can generate multi-order anti-Stokes light of red, green and blue in this wavelength range. The line width of the pump laser output by the 1μm pump source should be less than 0.1nm. In order to stimulate pure vibration stimulated Raman scattering, the linear polarization degree should be greater than 1000:1. In order to stimulate transient stimulated Raman scattering in a hollow-core optical fiber with a length of tens of centimeters (less than 1 meter), the pulse width of the pump laser output by the 1μm pump source should be less than 3ns. In order to reach the stimulated Raman scattering threshold and output efficiently, the peak power is higher than 30kW.

[0029] The gas mass flow controller (including the input end gas mass flow controller 3 and the output end gas mass flow controller 7) is connected to the corresponding small gas cavity (the input end small gas cavity 4, the output end small gas cavity 6) using a valved air pipe, which is used to control the gas flow flowing into the small gas cavity and the hollow-core optical fiber, and then accurately control the gas pressure in the gas cavity and the hollow-core optical fiber. It can withstand a maximum high pressure of 100 bar and can control the minimum inflation step to 0.1 bar.

[0030] The small gas cavity 4 at the input end and the small gas cavity 6 at the output end are sealed with a rubber ring inside, so that the output end of the hollow-core optical fiber is directly opposite to the laser output window of the small gas cavity 6 at the output end, and the laser output window of the small gas cavity 6 at the output end is highly transparent to visible light. The small gas cavity 4 at the input end and the small gas cavity 6 at the output end are both connected to an air guide tube with a valve, which is used to control the air pressure in the gas cavity, and then control the air pressure in the hollow-core optical fiber.

[0031] In order 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: The visible light fiber gas Raman laser provided in this embodiment is based on Figure 1 The structure shown includes a 1 μm pump source 1, a coupling lens 2, a gas mass flow controller at the input end 3, a small gas cavity at the input end 4, a hollow-core optical fiber 5, a small gas cavity at the output end 6, a gas mass flow controller at the output end 7, a collimating lens 8, and a visible light bandpass filter 9.

[0032] The 1 μm pump source 1 is a 1064 nm linearly polarized narrow linewidth high peak power pulse 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.

[0033] The hollow-core optical fiber 5 is an anti-resonant hollow-core optical fiber, which can transmit visible light and near-infrared laser light. The working gas filled in the hollow-core optical fiber 5 is hydrogen.

[0034] The collimating lens 8 has high transmittance to the visible light laser and can collimate the visible light laser for output.

[0035] The visible light bandpass filter 9 is a visible light bandpass filter, which is arranged outside the laser output window, and the central wavelength thereof is the anti-Stokes wavelength of hydrogen.

[0036] Other settings such as the input end gas mass flow controller 3, the input end small gas cavity 4, the output end small gas cavity 6, and the output end gas mass flow controller 7 can all adopt the same settings as the above-mentioned embodiments, and will not be repeated here.

[0037] In this embodiment, a 1064nm narrow linewidth high peak power pulse laser is used as a 1μm pump source 1. The pump laser is first coupled into the hollow core optical fiber 5 through a coupling lens 2. The core of the hollow core optical fiber 5 is filled with gas and the pump laser transmission is constrained at the same time, providing an ideal environment for the interaction between the working gas and the pump laser. The working gas filled into the hollow core optical fiber 5 is hydrogen. Starting from 0 bar pressure, the pressure is gradually increased with a step size of 1 bar pressure, and the pressure is adjusted to the highest output power of the red laser. By selecting a suitable pressure and utilizing 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 small gas cavity 6 at the output end, and the visible light laser is collimated and output to the visible light bandpass filter 9 through the collimating lens 8. The visible light bandpass filter 9 filters out the residual pump light and other non-target wavelength lasers before outputting.

[0038] The working gas is hydrogen, with a -1 The vibration frequency shift coefficient can shift the pump laser to red, green and blue lasers through the anti-Stokes process of stimulated Raman scattering.

[0039] The small gas cavity 4 at the input end and the small gas cavity 6 at the output end are sealed with rubber rings, and the output end of the hollow-core optical fiber faces the laser output window of the small gas cavity 6 at the output end, and the laser output window of the small gas cavity 6 at the output end is highly transparent to visible light. The small gas cavity 4 at the input end and the small gas cavity 6 at the output end are both connected to an air guide tube with a valve, and the other end of the air guide tube with the valve is connected to a corresponding gas mass flow controller. By controlling the flow rate of the gas flowing into the small gas cavity 4 at the input end, the small gas cavity 6 at the output end and the hollow-core optical fiber, a step-size increase in air pressure of 0.1 bar can be achieved, and the air pressure in the hollow-core optical fiber can be accurately controlled.

[0040] At the same time, the choice of pump laser wavelength determines the specific wavelength of the output visible light laser. The pump laser wavelength, anti-Stokes wavelength and the frequency shift coefficient of the gas molecules are determined by the following formula: ; In the formula λ p is the pump laser wavelength, λ as is the anti-Stokes wavelength, Ω R is the Raman frequency shift coefficient. 2 ) The molecule has a vibration frequency shift coefficient of 4155cm -1 The vibration Raman spectrum of the pump laser is 1064nm, and the first, second and third order anti-Stokes wavelengths are 738nm, 565nm and 457nm, respectively, corresponding to red, green and blue lasers.

[0041] refer to Figure 2 , which is a schematic diagram of the transmission loss of the hollow-core optical fiber in this embodiment, has low transmission loss for the 1064nm band of the pump laser wavelength, the 1.9μm band of the Stokes wavelength, and the anti-Stokes visible light band, but has high transmission loss for lasers in other bands.

[0042] Figure 3 The visible light fiber gas Raman laser provided in this embodiment is filled with 23 bar H 2 Output spectrum of . Figure 3 It can be seen that the average power of the coupled pump is charged with 23 barH 2 At the same time, red, green and blue laser outputs of 457nm, 565nm and 738nm are generated, indicating that the compact visible light fiber gas Raman laser provided by the present invention is operable.

[0043] Figure 4 For the visible light fiber gas Raman laser provided in this embodiment, 4 bar to 30 bar H2O is filled into the hollow core fiber core at 0 mW to 720 mW coupled pump laser power. 2 The influence of the output 738nm red laser average power. The corresponding coupled pump average power threshold of 738nm red light is 210mW. When the coupled pump average power is 720mW, at 4bar~30barH 2 Under pressure, as the pressure increases, the average power of 738nm red light output increases, reaching a maximum of 9.71mW at 23bar pressure; 2 Under air pressure, as the air pressure increases, the average power of the 738nm red light output decreases. Since the generation of 565nm green light and 457nm blue light is the same as that of 738nm red light, both are generated by the four-wave mixing effect, the influence trend of the output laser power of 565nm green light and 457nm blue light with the change of coupled pump power and air pressure is the same as that of 738nm red light, which will not be repeated here.

[0044] The effectiveness of the present invention is fully demonstrated through the above specific application embodiments and corresponding data and effect diagrams.

[0045] Furthermore, by precisely adjusting the gas pressure in the hollow-core 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 high conversion efficiency, thereby expanding the output wavelength range of existing fiber gas Raman lasers. In addition, the output of the fiber gas Raman laser will not be restricted by stimulated Brillouin scattering, and at the same time has the advantages of high beam quality and easy maintenance of general fiber lasers.

[0046] Matters not covered by the present invention are known technologies.

[0047] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0048] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

[0049] The above description is only a preferred embodiment of the present invention and is 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 in the protection scope of the present invention.

Claims

1. Visible light fiber gas Raman laser, characterized in that: Including 1μm pump source, hollow core fiber, working gas: 1μm pump source, output pump laser, wavelength range is 950nm-1080nm; The pump laser is coupled into the core of a hollow-core optical fiber sealed at both ends; The core of the hollow core optical fiber is filled with a working gas, which is hydrogen; The pump laser generates stimulated Raman scattering and four-wave mixing effects with hydrogen in the hollow-core optical fiber, generating and outputting anti-Stokes lasers in the red, green and blue visible light bands. The visible light bandpass filter 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 light beam of non-target wavelength output by the hollow-core optical fiber and outputs visible light of target wavelength.

2. The visible light fiber gas Raman laser according to claim 1, characterized in that: The 1 μm pump source is a 1 μm linearly polarized narrow linewidth high peak power pulse laser, with a linear polarization degree 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.

3. The visible light fiber gas Raman laser according to claim 1 or 2, characterized in that: The invention also comprises a coupling lens, which has high transmittance to the pump laser and focuses and couples the pump laser into the core of the hollow core optical fiber.

4. The visible light fiber gas Raman laser according to claim 3, characterized in that: The two ends of the hollow-core optical fiber are sealed by a small gas cavity at the input end and a small gas cavity at the output end. At least one of the small gas cavity at the input end and the small gas cavity at the output end is connected to a gas mass flow controller for evacuating the core of the hollow-core optical fiber, filling the core of the hollow-core optical fiber with working gas and controlling the gas flow of the working gas, thereby controlling the gas pressure in the small gas cavity at the input end, the small gas cavity at the output end and the core of the hollow-core optical fiber.

5. The visible light fiber gas Raman laser according to claim 4, characterized in that: The gas mass flow controller uses a valved air pipe connected to the corresponding small gas cavity to control the gas flow into the small gas cavity and the hollow-core optical fiber, thereby accurately controlling the gas pressure in the small gas cavity and the hollow-core optical fiber. It can withstand a maximum high pressure of 100 bar and can control the minimum inflation step to 0.1 bar.

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

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

8. The visible light fiber gas Raman laser according to claim 7, characterized in that: The hollow core optical fiber has low transmission loss for the 1064nm band of pump laser wavelength, the 1.9μm band of Stokes wavelength and the visible light band of anti-Stokes, but has high transmission loss for lasers in other bands.

9. The visible light fiber gas Raman laser according to claim 1 or 2 or 4 or 5 or 7 or 8, characterized in that: It also includes a collimating lens, which is arranged on one side of the output end of the hollow-core optical fiber. The collimating lens has a high transmittance to the visible light laser output from the hollow-core optical fiber, and collimates the visible light laser and outputs it to the visible light bandpass filter.

10. The visible light fiber gas Raman laser according to claim 9, characterized in that: The hollow-core optical fiber is an anti-resonance hollow-core optical fiber, which can transmit visible light and near-infrared band laser.

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