Ultra-narrow linewidth laser based on spatial light

Abstract

The present invention provides an ultra-narrow linewidth laser based on spatial light, including a laser generating gain device, a spatial coupling lens, a first lens with transmission and reflection characteristics, a convex lens and a spherical mirror arranged in sequence, the first lens is arranged vertically relative to the horizontal direction, the convex surface of the convex lens and the concave surface of the spherical mirror are arranged relative to each other, and a distributed scattering medium is arranged on the concave surface of the spherical mirror. The present invention transmits the spatial laser generated by the laser generating gain device to the gain medium on the spherical mirror, and the gain medium compresses the linewidth of the spatial laser to obtain a scattering signal with a narrower linewidth. The scattering signal is fed back to the laser generating gain device in the original path, and the laser generating gain device performs gain amplification on the received scattering signal, and the scattering signal after gain amplification is transmitted back to the distributed scattering medium as the spatial laser for linewidth compression. When equilibrium is reached, the optical signal reflected and output by the first lens undergoes multiple linewidth cycle deep compressions.

Description

Technical Field

[0001] The invention belongs to the technical field of narrow linewidth lasers, and in particular relates to an ultra-narrow linewidth laser based on spatial light. Background Art

[0002] Ultra-narrow linewidth lasers have the characteristics of high coherence, high integration and low phase noise, so they have very important application prospects in application fields such as laser radar and digital coherent transmission systems. So far, most of the research on laser linewidth characteristics has focused on the one-dimensional transmission process of waveguide light, and there are few detailed studies on the compression of spatial light width. As for the current methods for compressing the width of spatial light, such as using multi-mirror reflection and coupling as waveguide light and then using the external cavity method, all current methods have the disadvantages of either large systems, or requiring wavelength limitations and difficult direct control. Therefore, how to achieve deep compression of the laser linewidth of spatial light structures while ensuring simple structure and low cost is a difficult problem currently faced by this field. Summary of the invention

[0003] The present invention provides an ultra-narrow linewidth laser based on spatial light to solve the problem that the current device for deep compression of the linewidth of spatial light laser has a complex structure and a large volume.

[0004] According to the first aspect of the patent embodiment of the present invention, an ultra-narrow linewidth laser based on spatial light is provided, comprising a laser generating gain device, a spatial coupling lens, a first lens with transmission and reflection characteristics, a convex lens and a spherical mirror arranged in sequence, the convex surface of the convex lens and the concave surface of the spherical mirror are arranged oppositely, and a distributed scattering medium is arranged on the concave surface of the spherical mirror; the laser generating gain device is used to generate a spatial laser, and the spatial laser is emitted outward to the spatial coupling lens, and the spatial laser is coupled by the spatial coupling lens and transmitted to the first lens in the horizontal direction forward, and the first lens is inclined relative to the horizontal direction, and the first lens transmits a part of the spatial laser to the convex lens, and the other part is reflected and output; the convex lens emits the received spatial laser from its convex surface outward to the distributed scattering medium of the spherical mirror;

[0005] The distributed scattering medium compresses the line width of the received spatial laser to obtain a scattering signal with a narrower line width than the spatial laser. A part of the scattering signal can be transmitted back to the convex surface of the convex lens along the original route. After receiving the scattering signal, the convex lens transmits the scattering signal forward in the horizontal direction to the first lens along the original route. The first lens transmits a part of the scattering signal to the spatial coupling lens, and reflects and outputs the other part. The spatial coupling lens returns the received scattering signal to the laser generating gain device along the original route. The laser generating gain device performs gain amplification on the scattering signal, and then continues to emit the gain-amplified scattering signal as the spatial laser along the original route to the spatial coupling lens. When equilibrium is reached, the light signal reflected and output by the first lens is used as the output light of the laser. After multiple line width cycle deep compressions, an ultra-narrow line width laser is obtained.

[0006] In an optional implementation, the laser generating gain device is used to generate a spatial laser with a set diffusion angle. When a plurality of distributed scattering media are arranged on the concave surface of the spherical mirror and the scattering coefficients of the plurality of distributed scattering media are partially the same, the line width compression degree of the spatial laser is adjusted by changing the position at which the spatial laser is emitted to the spatial coupling lens and / or changing the distributed scattering medium to which the spatial laser emitted from the convex surface of the convex lens is aligned.

[0007] In another optional implementation, a plurality of distributed scattering media are arranged on the concave surface of the spherical mirror, and the scattering coefficients of the plurality of distributed scattering media are different. The laser generating gain device is used to generate a parallel beam type spatial laser, and the line width compression degree of the spatial laser is adjusted by changing the position where the spatial laser is emitted to the spatial coupling lens and / or changing the distributed scattering medium to which the spatial laser emitted from the convex surface of the convex lens is aligned.

[0008] In another optional implementation, the laser generating gain device is used to generate multiple spatial lasers with corresponding set diffusion angles, and each spatial laser with a corresponding set diffusion angle is respectively emitted to different positions of the spatial coupling lens, and the convex lens emits each received spatial laser to different distributed scattering media of the spherical mirror.

[0009] In another optional implementation, the laser generating gain device is used to generate multiple parallel beam type spatial lasers, each of which is emitted to a different position of the spatial coupling lens, and the convex lens emits each of the received spatial lasers to different distributed scattering media of the spherical mirror.

[0010] In another optional implementation, the scattering coefficient of the distributed scattering medium is increased so that the scattering signal output by the distributed scattering medium has a higher intensity, thereby further compressing the line width and reducing the size of the required distributed scattering medium; the line width compression degree of the spatial laser is changed by replacing the distributed scattering medium with a different scattering coefficient.

[0011] In another optional implementation, the distributed scattering medium is suitable for line width compression of laser light of any wavelength.

[0012] In another optional implementation, the emission angle range of the spatial laser from the convex surface of the convex lens to the spherical mirror is determined according to the refractive index and curvature of the convex lens.

[0013] In another optional implementation, the convex surface of the convex lens and the concave surface of the spherical mirror have equal curvature radii, the convex surface of the convex lens and the concave surface of the spherical mirror are concentric, and a sliding groove is provided under the spherical mirror. By sliding the spherical mirror along the sliding groove, the spherical mirror can be rotated around its center of circle, thereby changing the distributed scattering medium to which the spatial laser emitted from the convex surface of the convex lens is aimed, thereby adjusting the degree of line width compression of the spatial laser.

[0014] In another optional implementation, the distributed scattering medium is used to generate a multiple reflection characteristic of a scattered signal to achieve single longitudinal mode output of the laser.

[0015] The beneficial effects of the present invention are:

[0016] 1. The present invention sequentially arranges a laser generating gain device, a space coupling lens, a first lens, a convex lens and a spherical mirror, and arranges a gain medium on the spherical mirror. The space laser generated by the laser generating gain device can be sequentially transmitted to the gain medium on the spherical mirror through the space coupling lens, the first lens and the convex lens. The gain medium compresses the line width of the space laser to obtain a scattering signal with a narrower line width. The scattering signal is sequentially transmitted back to the laser gain medium through the convex lens, the first lens and the space coupling lens in the original path. The laser gain medium performs gain amplification on the received scattering signal, and the scattering signal after gain amplification is transmitted as the space laser to the distributed scattering medium again in the original path for line width compression. Since the first lens has transmission and reflection characteristics, Therefore, when the balance is reached, the optical signal reflected and output by the first lens is used as the output light of the laser, which has undergone deep line width cyclic compression, so that ultra-narrow line width laser can be obtained. The present invention combines the scattering principle and the spatial coupling lens to realize direct deep compression of the laser line width in three-dimensional space. The structure of the entire laser is simple, the volume is small, and the stability and scalability are good. In addition, the present invention compresses the line width of the spatial laser based on the scattering effect, and feeds back the obtained scattering signal with a narrower line width to the laser generating gain device. The laser generating gain device can suppress the side mode of the optical signal in the process of gain amplifying each scattered signal, so that the gain-amplified scattered signal output by the laser generating gain device has a high side mode suppression ratio.

[0017] 2. The present invention can perform line width cyclic compression on a single-channel space laser with a corresponding set diffusion angle, and can also perform line width cyclic compression on multiple-channel space lasers with corresponding set diffusion angles at the same time. In addition, by arranging multiple distributed scattering media on the concave surface of the spherical mirror and making the scattering coefficients of the multiple distributed scattering media partially the same, the line width compression degree of the space laser with the diffusion angle can be adjusted as needed;

[0018] 3. The present invention can perform line width cyclic compression on a single-path parallel beam type space laser, and can also perform line width cyclic compression on multiple parallel beam type space lasers at the same time, and by arranging multiple distributed scattering media on the concave surface of the spherical mirror and making the scattering coefficients of the multiple distributed scattering media partially the same, the line width compression degree of the parallel beam type space laser can be adjusted as needed;

[0019] 4. The present invention adjusts the scattering coefficient of the distributed scattering medium, so that the distributed scattering medium can output a high-intensity scattering signal, so that the scattering signal fed back to the convex surface of the convex lens along the original path also has a high intensity;

[0020] 5. The line width compression effect of the distributed scattering medium of the present invention is applicable to a laser generating gain device of any wavelength;

[0021] 6. The present invention can also adjust the degree of line width depth compression of spatial laser by changing the size and thickness of the distributed scattering medium without replacing the distributed scattering medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of an embodiment of an ultra-narrow linewidth laser based on spatial light of the present invention.

[0023] In the figure, the names corresponding to the various marks are: laser generating gain device 1, spatial coupling lens 2, first lens 3, convex lens 4, distributed scattering medium 5, and spherical mirror 6. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings, but is not limited to the following contents.

[0025] See also Figure 1 , is a structural schematic diagram of an ultra-narrow linewidth laser based on spatial light of the present invention. The ultra-narrow linewidth laser based on spatial light may include a laser generating gain device 1, a spatial coupling lens 2, a first lens 3 with transmission and reflection characteristics, a convex lens 4 and a spherical mirror 6 arranged in sequence, the convex surface of the convex lens 4 and the concave surface of the spherical mirror 6 are arranged oppositely, and a distributed scattering medium 5 is arranged on the concave surface of the spherical mirror 6; the laser generating gain device 1 is used to generate spatial laser, and emit the spatial laser outward to the spatial coupling lens 2, and the spatial laser is coupled by the spatial coupling lens 2 and transmitted to the first lens 3 in the horizontal direction in the front, and the first lens 3 is inclined relative to the horizontal direction, and the first lens 3 transmits a part of the spatial laser to the convex lens 4, and reflects the other part for output; the convex lens 4 emits the received spatial laser outward from its convex surface to the distributed scattering medium 5 of the spherical mirror 6.

[0026] The distributed scattering medium 5 compresses the line width of the received spatial laser to obtain a scattering signal with a narrower line width than the spatial laser. A part of the scattering signal can be transmitted back to the convex surface of the convex lens 4 along the original route. After receiving the scattering signal, the convex lens 4 transmits the scattering signal forward in the horizontal direction to the first lens 3 along the original route. The first lens 3 transmits a part of the scattering signal to the spatial coupling lens 2, and reflects the other part for output. The spatial coupling lens 2 returns the received scattering signal to the laser generating gain device 1 along the original route. The laser generating gain device 1 performs gain amplification on the scattering signal, and then continues to emit the gain-amplified scattering signal as the spatial laser along the original route to the spatial coupling lens 2. When equilibrium is reached, the light signal reflected and output by the first lens 3 is used as the output light of the laser. After multiple line width cycle deep compressions, an ultra-narrow line width laser is obtained.

[0027] In this embodiment, the laser generating gain device 1 may include all structures that can form lasers, such as conventional optical cavities and surface chips, and there is no spatial optical isolator inside, which is conducive to receiving subsequent feedback signals. The first lens 3 may be a semi-transparent and semi-reflective lens, and the spherical mirror 6 may be a hemispherical mirror. When the present invention performs line width cyclic compression on a spatial laser, the laser generating gain device 1 may be used to generate a spatial laser with a set diffusion angle, wherein the diffuse light center axis of the spatial laser may be on the same horizontal line as the center axis of the spatial coupling lens 2, the convex surface of the convex lens 4, and the concave surface of the spherical mirror 6, and at this time, the distributed scattering medium may be one. When the present invention performs line width cyclic compression on a spatial laser, by enabling the laser generating gain device to generate a spatial laser with a set diffusion angle, the line width compression rate of a single spatial laser can be improved. In addition, when a plurality of distributed scattering media 5 are arranged on the concave surface of the spherical mirror 6, and the scattering coefficients of the plurality of distributed scattering media 5 are partially the same, the line width compression degree of the spatial laser can be adjusted by changing the position where the spatial laser is emitted onto the spatial coupling lens 2 and / or changing the distributed scattering medium 5 to which the spatial laser emitted from the convex surface of the convex lens 4 is directed. For example, when the spherical mirror 6 is not in motion, the position where the spatial laser is emitted onto the spatial coupling lens 2 can be changed so that the distributed scattering medium to which the spatial laser emitted from the convex surface of the convex lens 4 is directed can be changed; when the position where the spatial laser is emitted onto the spatial coupling lens 2 remains unchanged, the spherical mirror can be rotated so that the distributed scattering medium to which the spatial laser emitted from the convex surface of the convex lens 4 is directed can be changed. Specifically, the convex surface of the convex lens 4 and the concave surface of the spherical mirror 6 have the same curvature radius, and the convex surface of the convex lens 4 and the concave surface of the spherical mirror 6 are concentric. A sliding groove is arranged below the spherical mirror 6. By sliding the spherical mirror 6 along the sliding groove, the spherical mirror 6 can be rotated around its center of the circle, and the distributed scattering medium 5 to which the spatial laser emitted from the convex surface of the convex lens 4 is directed is changed, thereby adjusting the line width compression degree of the spatial laser. When the line width compression degree needs to be increased, the spatial laser emitted from the convex surface of the convex lens 4 can be directed to the distributed scattering medium with a higher scattering coefficient; when the line width compression degree needs to be reduced, the spatial laser emitted from the convex surface of the convex lens 4 can be directed to the distributed scattering medium with a lower scattering coefficient. The present invention can adjust the line width compression degree of the spatial laser with a diffusion angle as needed by arranging multiple distributed scattering media on the concave surface of the spherical mirror and making the scattering coefficients of the multiple distributed scattering media partially the same.

[0028] The present invention can also perform line width cyclic compression on multiple spatial lasers with corresponding set diffusion angles at the same time. The laser generating gain device is used to generate multiple spatial lasers with corresponding set diffusion angles, and each spatial laser with a corresponding set diffusion angle is emitted to different positions of the spatial coupling lens respectively, and the convex lens emits each received spatial laser to different distributed scattering media of the spherical mirror respectively. When the line width cyclic compression is performed on multiple spatial lasers with corresponding set diffusion angles at the same time, the scattering coefficients of the distributed scattering media to which each spatial laser emitted from the convex surface of the convex lens 4 is aimed can be the same or different, and the wavelengths of the multiple spatial lasers can be the same or different.

[0029] In addition, the present invention can not only perform line width cyclic compression on a space laser with a diffusion angle, but also perform line width cyclic compression on a parallel beam type space laser. Among them, a plurality of distributed scattering media 5 can be arranged on the concave surface of the spherical mirror 6, and the scattering coefficients of the plurality of distributed scattering media 5 are different. The laser generating gain device 1 is used to generate a parallel beam type space laser, and the line width compression degree of the space laser is adjusted by changing the position of the space laser emitted to the space coupling lens 2 and / or changing the distributed scattering medium 5 to which the space laser emitted from the convex surface of the convex lens 4 is aimed. For example, when the spherical mirror 6 is not in motion, the position of the space laser emitted to the space coupling lens 2 can be changed so that the distributed scattering medium to which the space laser emitted from the convex surface of the convex lens 4 is aimed can be changed; when the position of the space laser emitted to the space coupling lens 2 remains unchanged, the spherical mirror can be rotated so that the distributed scattering medium to which the space laser emitted from the convex surface of the convex lens 4 is aimed can be changed. Specifically, the convex surface of the convex lens 4 and the concave surface of the spherical mirror 6 have the same curvature radius, the convex surface of the convex lens 4 and the concave surface of the spherical mirror 6 are concentric, a sliding groove is provided below the spherical mirror 6, each spatial laser emitted from the convex surface of the convex lens 4 is located on the same plane, each distributed scattering medium on the spherical mirror 6 intersects with the plane, and by sliding the spherical mirror 6 along the sliding groove, the spherical mirror 6 can be rotated around its center of circle to change the distributed scattering medium 5 to which the spatial laser emitted from the convex surface of the convex lens 4 is directed, thereby adjusting the line width compression degree of the spatial laser. When the line width compression degree needs to be increased, the spatial laser emitted from the convex surface of the convex lens 4 can be directed to the distributed scattering medium with a higher scattering coefficient; when the line width compression degree needs to be reduced, the spatial laser emitted from the convex surface of the convex lens 4 can be directed to the distributed scattering medium with a lower scattering coefficient. The present invention arranges a plurality of distributed scattering media on the concave surface of a spherical mirror, and makes the scattering coefficients of the plurality of distributed scattering media partially the same, so that the line width compression degree of the parallel beam type spatial laser can be adjusted as needed.

[0030] The present invention can also perform line width cyclic compression on multiple parallel beam type spatial lasers at the same time. The laser generating gain device 1 is used to generate multiple parallel beam type spatial lasers, each of which is emitted to different positions of the spatial coupling lens 2, and the convex lens 4 emits the received each of the spatial lasers to different distributed scattering media of the spherical mirror 6. When the line width cyclic compression is performed on multiple parallel beam type spatial lasers at the same time, the scattering coefficients of the distributed scattering media to which each of the spatial lasers emitted from the convex surface of the convex lens 4 is aimed can be the same or different, and the wavelengths of the multiple spatial lasers can be the same or different.

[0031] When there are multiple distributed scattering media on the concave surface of the spherical mirror 6, the multiple distributed scattering media can be arranged at intervals and can be arranged at uniform intervals. At this time, after receiving the spatial laser, the convex lens 4 emits the spatial laser from its convex surface to the distributed scattering medium 5 of the spherical mirror 6; the distributed scattering medium 5 compresses the line width of the received spatial laser to obtain a scattering signal with a narrower line width than the spatial laser, and a part of the scattering signal can be transmitted back to the convex surface of the convex lens 4 along the original path. Due to the reversibility of the optical path and the randomness of the direction of the scattering process, there must be a scattering signal that can be fed back to the laser generating gain device 1 along the original path of the system. However, precisely because the direction of the feedback transmission of the scattered signal is random, the scattered signal generated by the distributed scattering medium 5 is less than the scattered signal transmitted to the convex surface of the convex lens 4 along the original path. In order to make the intensity of the scattered signal transmitted to the convex surface of the convex lens along the original path larger, the scattering coefficient of the distributed scattering medium can be increased to make the scattered signal output by the distributed scattering medium 5 have a higher intensity, thereby further compressing the line width and reducing the size of the required distributed scattering medium. Among them, the distributed scattering medium can be a medium with a certain thickness attached to the concave surface of the spherical mirror 6. The present invention can construct the medium by doping metal elements "such as germanium, sodium, etc." into the medium, or using additives "such as metal oxide nanoparticles and monomers / polymers containing a high atomic number (compared to the number of carbon atoms)" for the medium, or using various materials with a high refractive index "such as a series of high refractive index polymers based on aromatic and brominated aromatic monomers" to make the scattering signal output by the distributed scattering medium have a higher intensity.

[0032] In addition, the distributed scattering medium in the present invention is suitable for line width compression of lasers of any wavelength, and the wavelengths of spatial lasers can be different. Therefore, the laser of the present invention can achieve deep line width compression of spatial lasers of different wavelengths. When the line width of a spatial laser with a diffusion angle is cyclically compressed, after the convex lens 4 receives the spatial laser, the range of the emission angle of the spatial laser from the convex surface of the convex lens to the spherical mirror is determined according to the refractive index and curvature of the convex lens. The present invention uses the multiple reflection characteristics of the distributed scattering medium to generate the scattered signal to achieve the single longitudinal mode output of the laser. Generally speaking, the equilibrium state of laser output refers to the state in which the gain and loss of the emitted laser in the laser generating gain device reach a balanced state. After the external scattering signal is introduced here, it can be expressed as the gain coefficient and loss coefficient of the scattered signal in the laser generating gain device reach a balance, which is manifested externally as the laser line width and laser power being stable. During the use of the laser, the user may need to adjust the degree of line width compression of the laser. At this time, the degree of line width compression of the spatial laser is changed by replacing the distributed scattering medium with different scattering coefficients.

[0033] It can be seen from the above embodiments that the present invention sequentially arranges a laser generating gain device, a spatial coupling lens, a first lens, a convex lens and a spherical mirror, and arranges a gain medium on the spherical mirror, so that the spatial laser generated by the laser generating gain device can be transmitted to the gain medium on the spherical mirror through the spatial coupling lens, the first lens and the convex lens in sequence, and the gain medium compresses the line width of the spatial laser to obtain a scattering signal with a narrower line width. The scattering signal is sequentially fed back to the laser gain medium through the convex lens, the first lens and the spatial coupling lens in the original path, and the laser gain medium performs gain amplification on the received scattering signal, and the scattering signal after gain amplification is transmitted as the spatial laser to the distributed scattering medium again in the original path for line width compression. Since the first lens has a transmission and reflection characteristics, so when equilibrium is reached, the light signal reflected and output by the first lens is used as the output light of the laser, and has undergone line width cyclic deep compression, so that ultra-narrow line width laser can be obtained. The present invention combines the scattering principle and the spatial coupling lens to realize direct deep compression of the laser line width in three-dimensional space. The structure of the entire laser is simple, the volume is small, and the stability and scalability are good. In addition, the present invention compresses the line width of the spatial laser based on the scattering effect, and feeds the obtained scattering signal with a narrower line width back to the laser generating gain device. The laser generating gain device can suppress the side mode of the light signal during the process of gain amplifying the scattered signals of each path, so that the gain-amplified scattered signal output by the laser generating gain device has a high side mode suppression ratio.

[0034] During the operation of the laser, since scattering exists in the transmission of lasers of any wavelength, no matter what wavelength drift the spatial laser output by the laser generating gain device 1 produces due to external environmental factors or internal self-oscillation, a scattering signal will be generated in the distributed scattering medium 5 and fed back to the laser generating gain device 1 to achieve deep compression of the line width. It should be noted that the distributed scattering medium can contain various structures or materials that can enhance the scattering coefficient. The wavelength output from the laser generating gain device can be selected arbitrarily, and the invention does not have wavelength selectivity in the process of deep compression of the line width of different laser wavelengths. In addition, the technology provided by this patent is applicable to original laser generating structures of both semiconductor type and fiber laser gain type.

[0035] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0036] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. An ultra-narrow linewidth laser based on spatial light, characterized in that: The invention comprises a laser generating gain device, a space coupling lens, a first lens with transmission and reflection characteristics, a convex lens and a spherical mirror which are arranged in sequence, wherein the convex surface of the convex lens and the concave surface of the spherical mirror are arranged opposite to each other, and a distributed scattering medium is arranged on the concave surface of the spherical mirror; the laser generating gain device is used to generate space laser, and emit the space laser outward to the space coupling lens; the space laser is coupled by the space coupling lens and transmitted to the first lens in a forward horizontal direction; the first lens is arranged tilted relative to the horizontal direction; the first lens transmits a part of the space laser to the convex lens, and reflects and outputs the other part; the convex lens emits the received space laser outward from its convex surface to the distributed scattering medium of the spherical mirror; The distributed scattering medium performs line width compression on the received spatial laser to obtain a scattering signal with a narrower line width than the spatial laser. A portion of the scattering signal can be transmitted back to the convex surface of the convex lens along the original path. After receiving the scattering signal, the convex lens transmits the scattering signal forward in the horizontal direction to the first lens along the original path. The first lens transmits a portion of the scattering signal to the spatial coupling lens, and the other portion is reflected and output; the spatial coupling lens returns the received scattering signal to the laser generating gain device along the original path, and the laser generating gain device performs gain amplification on the scattering signal, and then continues to emit the gain-amplified scattering signal as the spatial laser along the original path to the spatial coupling lens; when equilibrium is reached, the optical signal reflected and output by the first lens is used as the output light of the laser, and after multiple line width cycle deep compressions, an ultra-narrow line width laser is obtained; By increasing the scattering coefficient of the distributed scattering medium, the scattered signal output by the distributed scattering medium has a higher intensity, thereby further compressing the line width and reducing the size of the required distributed scattering medium; by replacing the distributed scattering medium with different scattering coefficients, the line width compression degree of the spatial laser is changed; The distributed scattering medium is suitable for line width compression of laser light of any wavelength.

2. The ultra-narrow linewidth laser based on spatial light according to claim 1, characterized in that: The laser generating gain device is used to generate a spatial laser with a set diffusion angle. When a plurality of distributed scattering media are arranged on the concave surface of the spherical mirror and the scattering coefficients of the plurality of distributed scattering media are partially the same, the line width compression degree of the spatial laser is adjusted by changing the position at which the spatial laser is emitted to the spatial coupling lens and / or changing the distributed scattering medium to which the spatial laser emitted from the convex surface of the convex lens is aimed.

3. The ultra-narrow linewidth laser based on spatial light according to claim 1, characterized in that: A plurality of distributed scattering media are arranged on the concave surface of the spherical mirror, and the scattering coefficients of the plurality of distributed scattering media are different. The laser generating gain device is used to generate a parallel beam type spatial laser, and the line width compression degree of the spatial laser is adjusted by changing the position where the spatial laser is emitted to the spatial coupling lens and / or changing the distributed scattering medium to which the spatial laser emitted from the convex surface of the convex lens is aimed.

4. The ultra-narrow linewidth laser based on spatial light according to claim 2, characterized in that: The laser generating gain device is used to generate multiple spatial lasers with corresponding set diffusion angles, and each spatial laser with a corresponding set diffusion angle is emitted to different positions of the spatial coupling lens respectively, and the convex lens emits each received spatial laser to different distributed scattering media of the spherical mirror respectively.

5. The ultra-narrow linewidth laser based on spatial light according to claim 3, characterized in that: The laser generating gain device is used to generate multiple parallel beam type spatial lasers, each of which is emitted to different positions of the spatial coupling lens, and the convex lens emits each of the received spatial lasers to different distributed scattering media of the spherical mirror.

6. The ultra-narrow linewidth laser based on spatial light according to claim 2, characterized in that: The emission angle range of the spatial laser from the convex surface of the convex lens to the spherical mirror is determined by the refractive index and curvature of the convex lens.

7. The ultra-narrow linewidth laser based on spatial light according to any one of claims 2 to 5, characterized in that: The convex surface of the convex lens and the concave surface of the spherical mirror have the same curvature radius, and the convex surface of the convex lens and the concave surface of the spherical mirror are concentric. A sliding groove is arranged under the spherical mirror. By sliding the spherical mirror along the sliding groove, the spherical mirror can be rotated around its center of circle, thereby changing the distributed scattering medium to which the spatial laser emitted from the convex surface of the convex lens is aimed, thereby adjusting the line width compression degree of the spatial laser.

8. The ultra-narrow linewidth laser based on spatial light according to claim 1, characterized in that: The distributed scattering medium is used to generate multiple reflection characteristics of scattered signals to achieve single longitudinal mode output of laser.

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