A hybrid cavity laser device

Abstract

The application discloses a kind of hybrid cavity laser devices, including solid laser medium, pump source, first cavity mirror, second cavity mirror, folding mirror and doctor blade mirror;The pump source is used to provide pump light for solid laser medium;The solid laser medium is used to generate laser gain, the laser fast axis direction of the solid laser medium is Y axis direction, and the laser slow axis direction is Z axis direction;The first cavity mirror and second cavity mirror constitute optical resonator, for oscillating laser;First cavity mirror and second cavity mirror constitute unstable cavity structure in laser fast axis direction, and constitute stable cavity structure in laser slow axis direction;Folding mirror is arranged between solid laser medium and second cavity mirror, and folding mirror is used to fold cavity length in unstable cavity direction, and is used to increase the divergence angle of laser beam in stable cavity direction, increase fundamental mode volume;Doctor blade mirror is arranged in unstable cavity structure, for adjusting laser intensity and laser direction in unstable cavity structure;Laser beam generated by laser device is output through second cavity mirror or doctor blade mirror.

Description

Technical Field

[0001] The present invention relates to the field of solid-state laser technology, and more particularly to a hybrid cavity laser device. Background Art

[0002] Slab lasers, using large-aperture laser materials as gain media, can produce high-power laser output and are widely used in fields such as materials processing, medical treatment, and defense. These applications place high demands on both output power and beam quality. However, slab lasers with a stable cavity structure suffer from limited output power and poor beam quality due to the fundamental mode size restrictions imposed by the stable cavity design. Slab lasers with an unstable cavity structure can increase the laser mode radius and improve beam quality. However, the unstable cavity structure introduces aperture differences in two directions, affecting beam symmetry. Slab lasers with a hybrid unstable and stable cavity structure combine the advantages of both stable and unstable cavities, effectively compensating for beam aperture differences in different directions. This improves beam quality while enhancing overall laser performance and stability. However, due to mode volume limitations, it is difficult to achieve a large fundamental mode gain volume in the stable cavity direction, limiting the ability to achieve high-power, high-beam-quality laser output in that direction. Summary of the Invention

[0003] The present invention provides a hybrid cavity laser device to solve at least one of the problems existing in the prior art.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a hybrid cavity laser device, which includes a solid laser medium, a pump source, a first cavity mirror, a second cavity mirror, a folding mirror and a scraper mirror;

[0006] The pump source is used to provide pump light for the solid laser medium;

[0007] The solid laser medium is used to generate laser gain, the width direction of the solid laser medium is the Y-axis direction, which is the laser fast axis direction, and the thickness direction of the solid laser medium is the Z-axis direction, which is the laser slow axis direction;

[0008] The first cavity mirror and the second cavity mirror are respectively arranged on both sides of the end face of the solid laser medium, and the first cavity mirror and the second cavity mirror constitute an optical resonant cavity for oscillating laser;

[0009] The first cavity mirror and the second cavity mirror form an unstable cavity structure in the direction of the laser fast axis, and the first cavity mirror and the second cavity mirror form a stable cavity structure in the direction of the laser slow axis;

[0010] The folding mirror is arranged between the solid laser medium and the second cavity mirror, and is used for folding the cavity length in the unstable cavity structure, and is used for increasing the divergence angle of the laser beam in the stable cavity structure.

[0011] The scraper mirror is arranged in the unstable cavity structure, and is used for adjusting the laser intensity and the laser direction in the unstable cavity structure.

[0012] The laser beam generated by the laser device is output through the second cavity mirror or the scraper mirror.

[0013] Optionally, the folding mirror in the unstable cavity structure is a plane folding mirror.

[0014] The folding mirror in the stable cavity structure is a concave folding mirror or a convex folding mirror.

[0015] Optionally, the number of the folding mirrors is one or more.

[0016] Optionally, the first cavity mirror in the unstable cavity structure is a first concave mirror, and the second cavity mirror in the unstable cavity structure is a second concave mirror or a convex mirror.

[0017] The first cavity mirror in the stable cavity structure is a first concave mirror, and the second cavity mirror in the stable cavity structure is a plane mirror.

[0018] Optionally, the unstable cavity structure is a positive branch unstable cavity structure or a negative branch unstable cavity structure.

[0019] Optionally, the unstable cavity structure is a coaxial unstable cavity structure or an off-axis unstable cavity structure.

[0020] Optionally, the solid laser medium is a solid laser medium with a rectangular, trapezoidal or elliptical shape in the light transmission direction.

[0021] Optionally, an angle is arranged between the scraper mirror and the optical resonant cavity optical axis, and the scraper mirror is a hole scraper mirror or a solid scraper mirror.

[0022] Optionally, the scraper mirror is a hole scraper mirror, and the focal points of the first cavity mirror and the second cavity mirror coincide with the parallel light center axis of the hole scraper mirror.

[0023] The scraper mirror is a solid scraper mirror, and the solid scraper mirror is arranged on one side of the solid laser medium.

[0024] Optionally, the scraper mirror is coated with a high-reflection film of laser on the side surface close to the folding mirror, and is used for reflecting the output laser beam.

[0025] The beneficial effects of the present application are as follows:

[0026] The mixed cavity laser device provided by the application adds a folding mirror in an optical resonant cavity, changes the propagation direction of the laser beam through the folding mirror, expands the beam in the stable cavity direction, increases the divergence angle of the laser beam, increases the fundamental mode volume, reduces the number of transverse modes, increases the fundamental mode volume of the stable cavity structure while keeping the fundamental mode volume of the unstable cavity structure, and thus has a high-power and high-beam-quality laser beam in both the unstable cavity and stable cavity directions. BRIEF DESCRIPTION OF DRAWINGS

[0027] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings.

[0028] Figure 1 A schematic diagram of the mixed cavity laser device of the application is shown;

[0029] Figure 2 A schematic diagram of the mixed cavity slab laser device of the application in the direction of the top view of the coaxial unstable cavity structure is shown;

[0030] Figure 3 A schematic diagram of the mixed cavity slab laser device of the application in the direction of the top view of the off-axis unstable cavity structure is shown;

[0031] Figure 4 A schematic diagram of the mixed cavity slab laser device of the application in the direction of the front view of the stable cavity structure is shown;

[0032] Figure 5 A schematic diagram of the mixed cavity slab laser device of the application in the direction of the front view of the stable cavity structure without using a folding mirror is shown. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the application, the application will be further described below with reference to the preferred embodiments and the accompanying drawings. Similar components are denoted by the same reference numerals in the drawings. Those skilled in the art should understand that the specific description below is illustrative rather than limiting, and should not limit the protection scope of the application.

[0034] The application provides a mixed cavity laser device, Figure 1 A schematic diagram of the mixed cavity laser device, which comprises a solid laser medium, a pump source, a first cavity mirror, a second cavity mirror, a folding mirror, and a scraper mirror;

[0035] The pump source is used to provide pump light for the solid laser medium, and the pump source is arranged on at least one end surface, large surface, or side surface of the solid laser medium. The pump source can be an LD array. The pump light is coupled into the solid laser medium through at least one end surface, large surface, or side surface of the solid laser medium after beam shaping;

[0036] The solid laser medium is used for generating laser gain, and the solid laser medium is a solid laser medium with a cross section of a light passing direction in a rectangular, trapezoidal or elliptical shape;

[0037] In the unstable and stable hybrid cavity laser device, the solid laser medium with an irregular shape such as a rectangular, trapezoidal or elliptical shape is selected for the cross section of the light passing direction, so as to optimize the propagation characteristics and mode control of the laser beam in the resonant cavity.

[0038] By controlling the geometric distribution of the laser beam through the laser medium with a cross section of a rectangular, trapezoidal or elliptical shape, the laser beam can achieve better divergence on the unstable cavity structure, thereby meeting the mode requirements in the cavity. The unstable cavity structure and the stable cavity structure have different requirements for the laser mode. The selection of the irregularly shaped laser medium can adjust the mode characteristics in the stable cavity direction while maintaining the appropriate fundamental mode volume on the unstable cavity structure. The selection of the irregularly shaped laser medium can better cooperate with the folding mirror design, optimize the spatial distribution and propagation mode of the laser beam in the cavity, and thereby improve the efficiency and stability of the laser output. The laser medium with an irregularly shaped cross section of the light passing direction can also effectively avoid the mode competition problem that may be caused by the circular medium. By precisely designing the shape of the medium to adjust the laser mode structure, the quality of the output beam can be controlled, unnecessary high-order modes can be avoided, and the performance of the laser can be ensured. The selection of the laser medium with an irregularly shaped cross section of the light passing direction such as a rectangular, trapezoidal or elliptical shape can better meet the requirements of the unstable cavity and the stable cavity, optimize the divergence, propagation and mode characteristics of the laser beam, and thereby improve the overall efficiency and stability of the laser device.

[0039] The first cavity mirror and the second cavity mirror are respectively arranged on both sides of the end face of the solid laser medium, and the first cavity mirror and the second cavity mirror constitute an optical resonant cavity for oscillating laser;

[0040] The first cavity mirror and the second cavity mirror constitute an unstable cavity structure in the fast axis direction of the laser, and constitute a stable cavity structure in the slow axis direction of the laser. The unstable cavity structure is a positive branch unstable cavity structure or a negative branch unstable cavity structure. The unstable cavity structure can also be a coaxial unstable cavity structure or an off-axis unstable cavity structure.

[0041] In the unstable cavity structure, the first cavity mirror is a first concave mirror, and the second cavity mirror is a second concave mirror or a convex mirror. In the stable cavity structure, the first cavity mirror is a first concave mirror, and the second cavity mirror is a flat mirror.

[0042] The folding mirror is arranged between the solid laser medium and the second cavity mirror. In the unstable cavity structure, the folding mirror is a flat folding mirror for folding the cavity length. In the stable cavity structure, the folding mirror is a concave folding mirror or a convex folding mirror for increasing the divergence angle of the laser beam, increasing the fundamental mode volume and improving the beam quality. The number of folding mirrors in the laser device can be one or more.

[0043] The scraper mirror is arranged between the second cavity mirror and the folding mirror, and is used to adjust the laser intensity and laser direction in the unstable cavity structure. An angle is set between the scraper mirror and the optical axis of the optical resonant cavity. The laser intensity and laser direction are adjusted by adjusting the angle and position between the scraper mirror and the optical resonant cavity. The scraper mirror is an open-hole scraper mirror or a solid scraper mirror. When the scraper mirror is an open-hole scraper mirror, the focal points of the first cavity mirror and the second cavity mirror coincide with the parallel light center axis of the open-hole scraper mirror. When the scraper mirror is a solid scraper mirror, the solid scraper mirror is placed away from the solid laser medium.

[0044] The surface of the open-hole scraper mirror close to the folding mirror (except the open hole) is coated with a high-reflective film for laser, which is used to reflect the output laser beam; the surface of the solid scraper mirror close to the folding mirror is coated with a high-reflective film for laser, which is used to reflect the output laser beam; the surface of the first cavity mirror close to the slab laser medium is coated with a high-reflective film for laser, and the surface of the second cavity mirror close to the folding mirror is coated with a partial anti-reflective film for laser, wherein the reflectivity of the high-reflective film for laser is greater than 99%.

[0045] The laser beam generated by the laser device is output through the second cavity mirror or the scraper mirror.

[0046] The hybrid cavity laser device provided by the present invention incorporates a folding mirror structure within the hybrid cavity and laser device, increasing the volume of the fundamental mode in the stable cavity direction while maintaining a large volume of the unstable cavity fundamental mode, thereby improving beam quality. The folding mirror changes the propagation direction of the laser beam, causing it to expand in the stable cavity direction, thereby increasing the volume of the fundamental mode. A larger fundamental mode volume reduces the number of oscillating transverse modes, resulting in a laser beam with high output power and high beam quality in both the stable and unstable cavity directions.

[0047] In a specific embodiment, the solid laser medium is a slab laser medium. Figure 2 The schematic diagram of the top view of the hybrid cavity slab laser device in the coaxial unstable cavity structure is shown. The device includes a slab laser medium 1, a pump source (the pump source is not in the Figure 2 As shown in the figure), an optical resonant cavity composed of a first cavity mirror and a second cavity mirror, and a folding mirror and a scraper mirror located in the optical resonant cavity, wherein in the unstable cavity structure, the first cavity mirror is a first concave mirror 2, the second cavity mirror is a second concave mirror 3, the folding mirror is a plane folding mirror 4, and the scraper mirror is an aperture scraper mirror 5, Figure 2 The direction of the arrow in the middle is the laser output direction, and the X-axis direction is the light transmission direction.

[0048] The active ions in the slab laser medium 1 include at least one of Nd, Yb, Ti, Pr, Cr, Tm or Ho, and / or the matrix material of the slab laser medium 1 includes at least one of crystal, glass and ceramic. Figure 2The X-axis is the length of the slab laser medium, the Y-axis is the width of the slab laser medium, and the Z-axis is the thickness of the slab laser medium. The length of the slab laser medium is greater than the width, and the thickness is greater than the thickness. The width of the slab laser medium is the fast axis of the laser, and the thickness of the slab laser medium is the slow axis of the laser. The slab laser medium has six faces. The large faces usually refer to the two faces orthogonal to the thickness direction. The large faces have the largest area and can be used to install cooling devices. The pump source is usually pumped from the large faces. The side faces usually refer to the two faces orthogonal to the width direction. Pumping can also be done from the side faces. The end faces usually refer to the two faces perpendicular to the light transmission direction. They are the faces from which the laser is output from the slab laser medium 1 and can also be pumped from the end faces. The cross-section of the solid laser medium in the light transmission direction can also be an irregular polygon such as a rectangle or an ellipse.

[0049] A pump source, such as a stacked LD array, provides pump light for the slab laser medium 1 and is located on at least one end face, side face, or large surface of the slab laser medium 1. After beam shaping, the pump light is coupled into the slab laser medium 1 through at least one end face, side face, or large surface of the slab laser medium 1.

[0050] The resonant cavity includes a first concave mirror 2 and a second concave mirror 3, respectively disposed on either side of the end face of a slab laser medium 1, and a flat folding mirror 4 disposed between the slab laser medium 1 and the second concave mirror 3. The first concave mirror 2 and the second concave mirror 3 constitute an optical resonant cavity for oscillating the laser. The first concave mirror 2 and the second concave mirror 3 constitute an unstable cavity structure along the laser fast axis and a stable cavity structure along the laser slow axis. The unstable cavity structure formed along the laser fast axis can be a positive-branch unstable cavity structure or a negative-branch unstable cavity structure. In the unstable cavity structure, the second cavity mirror can also be a convex mirror. In the resonant cavity, the unstable cavity structure formed along the laser fast axis can also be a coaxial unstable cavity structure or an off-axis unstable cavity structure.

[0051] The plane mirror 4 is used to fold the cavity length in an unstable cavity structure and to increase the divergence angle of the laser beam, increase the fundamental mode volume, and improve the beam quality in a stable cavity structure. The number of the plane folding mirrors 4 can be one or more.

[0052] The scraper mirror arranged between the second concave mirror 3 and the flat folding mirror 4 is used to act as an aperture inside the resonant cavity and reflect the output laser beam to the outside of the resonant cavity. An angle is set between the scraper mirror and the optical axis of the resonant cavity. According to the requirements of the laser beam emission, the angular position and reflectivity of the scraper mirror are adjusted to control the intensity and direction of the output laser.

[0053] Figure 2The scraper mirror in the image is a perforated scraper mirror 5. The position of the laser beam in the optical path is controlled by the light hole of the perforated scraper mirror 5, thereby controlling the light aperture of the laser. During the round trip of the optical path of the unstable cavity structure, in the direction of the laser fast axis, the parallel collimated laser emitted from the slab laser medium 1 is reflected by the slab laser medium 1 and the plane folding mirror 4. Part of the laser passes through the light hole of the perforated scraper mirror 5, forming resonance. This part of the laser is reflected by the second concave mirror 3, and then passes through the common focus with the first concave mirror 2. It coincides with the central axis of the parallel light passing through the scraper mirror, that is, the central axis perpendicular to the width direction of the slab medium. When it reaches the first concave mirror 2, it can diverge to the full aperture of the light spot, that is, reach the same aperture as the end face of the slab laser medium 1. Due to the angle between the perforated scraper mirror 5 and the optical axis of the resonant cavity, the laser reflected back from the first concave mirror 2 becomes a parallel collimated laser again. The generated laser can be output through the perforated scraper 5 and the second concave mirror 3. In the coaxial unstable cavity structure, the side of the perforated scraper mirror 5 close to the plane folding mirror 4 (except the light hole) is coated with a high-reflective film for laser. Part of the laser beam passes through the light hole of the perforated scraper mirror 5 to reach the second concave mirror 3, and the laser beam that does not pass through the light hole is reflected and output by the perforated scraper mirror 5.

[0054] The focal points of the first concave mirror 2 and the second concave mirror 3 coincide with the central axis of the parallel light passing through the aperture scraper mirror 5, that is, the central axis perpendicular to the width direction of the slab laser medium 1. Therefore, the laser passing through the light hole of the aperture scraper mirror 5 is symmetrical about the laser fast and slow axis of the slab laser medium 1, and the laser reflected by the aperture scraper mirror 5 is also symmetrical about the laser fast and slow axis of the slab laser medium 1.

[0055] Figure 3 This is a schematic diagram of the off-axis unstable cavity structure of the hybrid cavity laser device in the top view direction. In the off-axis unstable cavity structure, the laser beam does not propagate along the central axis, but along a path deviated from the cavity axis. Figure 3 The direction of the arrow in the middle is the laser output direction. The similarities between the off-axis unstable cavity structure and the above-mentioned coaxial unstable cavity structure are not repeated here.

[0056] The off-axis unstable cavity structure includes a slab laser medium 1, a first concave mirror 2, a second concave mirror 3, a plane folding mirror 4, a scraper mirror and a pump source (the pump source is at Figure 3(not shown), wherein the scraper mirror is a solid scraper mirror 6, i.e., a scraper mirror without openings. The solid scraper mirror 6 is placed differently from the perforated scraper mirror 5. The solid scraper mirror 6 needs to be placed offset to one side of the width direction of the slab laser medium 1. The positions of the first concave mirror 2 and the second concave mirror 3 are adjusted accordingly, so that the overlapping focal points of the first concave mirror 2 and the second concave mirror 3 are located on the parallel light center axis of the solid scraper mirror 6. This achieves the effect that the parallel collimated laser light passing through the solid scraper mirror 6, after being reflected by the second concave mirror 3 and reaching the first concave mirror 2, diverges to the same diameter as the end face of the slab laser medium 1.

[0057] The surface of the second concave mirror 3 close to the plane folding mirror 4 is coated with a partial anti-reflection film of the laser, and the surface of the solid scraper mirror 6 close to the plane folding mirror 4 is coated with a high-reflection film of the laser, wherein the reflectivity of the high-reflection film of the laser is greater than 99%, and the transmittance and reflectivity of the partial anti-reflection film of the laser are set according to actual conditions.

[0058] The solid scraper mirror 6 is placed on one side of the width direction of the slab laser medium 1 to form a laser path. Part of the laser reaches the second concave mirror 3 and is transmitted through the second concave mirror 3 to output the laser beam. The other part of the laser that does not pass through the laser path is reflected and output through the solid scraper mirror 6.

[0059] By adjusting the angular position and reflectivity of the solid scraper mirror 6, controlling the intensity and direction of the output laser beam, and adjusting the positions of the first concave mirror 2 and the second concave mirror 3, the divergence angle of the laser beam reaching the first concave mirror 2 after being reflected by the second concave mirror 3 is the same as the end face aperture of the slab laser medium 1.

[0060] In the direction of the laser slow axis, Figure 4 This is a schematic diagram of the front view of the stable cavity structure in the hybrid cavity slab laser device, which includes a slab laser medium 1, a first cavity mirror, a second cavity mirror, a folding mirror and a pump source (the pump source is at Figure 4 (not shown in the figure), wherein the first cavity mirror is a first concave mirror 2, the second cavity mirror is a plane mirror 7, the folding mirror is a convex folding mirror 8, and the folding mirror can also be a concave folding mirror. The first concave mirror 2 and the plane mirror 7 constitute an optical resonant cavity, and the laser resonates stably between the first concave mirror 2 and the plane mirror 7.

[0061] Taking the convex folding mirror 8 as an example, during the laser oscillation process, the divergence angle of the laser beam and the spot area of ​​the laser beam in the cavity are changed by adjusting the angle and position of the convex folding mirror 8. By increasing the divergence angle of the laser beam, the diameter of the laser beam increases within the oscillation cavity, which increases the spot area of ​​the laser beam in the cavity, thereby increasing the fundamental mode volume. The laser light emitted by the slab laser medium 1 is refracted by the curved surface of the convex folding mirror 8, thereby changing the propagation direction of the laser light. After being refracted to the plane mirror 7, the laser light is reflected by the plane mirror 7. After refraction by the convex folding mirror 8 and transmission by the slab laser medium 1, the spot diameter is increased when it reaches the first concave mirror 2, so that the spot area returning to the first concave mirror 2 is larger than the spot area output from the end face of the slab laser medium 1. That is, the spot of the laser beam becomes wider during propagation, and the light field of the fundamental mode volume can cover a wider area, which contributes to the uniformity of the light field and the stability of the mode.

[0062] Figure 5 This is a schematic diagram of a front view of a hybrid cavity slab laser device without a folding mirror in the cavity stabilization structure. The convex folding mirror 8 in the cavity stabilization structure is replaced with a plane mirror 9. During laser oscillation, adjusting the angle and position of plane mirror 9 results in no significant increase in the spot area of ​​laser light emitted from the end face of the slab laser medium 1, reflected by plane mirror 9, then reflected by plane mirror 7, and finally reflected by plane mirror 9 before reaching the first concave mirror 2. Therefore, adjusting the angle and position of plane mirror 9 does not significantly increase the laser beam divergence angle or the spot area within the cavity, and thus does not significantly increase the fundamental mode volume. Therefore, the convex folding mirror 8, through its optical properties, modifies the laser beam divergence angle, resulting in a larger spot size within the cavity, thereby increasing the volume of the fundamental mode. A larger spot area stabilizes the fundamental mode and reduces competition among higher-order modes. Therefore, expanding the fundamental mode volume facilitates mode selection in the laser device, improving the output quality and consistency of the laser light, and increasing the volume of the fundamental mode within the laser oscillation cavity, thereby optimizing the laser beam quality along the slow axis.

[0063] The present invention incorporates a folding mirror structure within the hybrid cavity, increasing the volume of the fundamental mode in the stable cavity direction while maintaining a large volume in the unstable cavity. This changes the propagation direction of the laser beam, causing it to expand in the stable cavity direction, thereby increasing the volume of the fundamental mode and improving beam quality. Increasing the volume of the fundamental mode through the folding mirror reduces the number of transverse modes that initiate oscillation, resulting in a laser beam with high beam quality in both the stable and unstable cavity directions.

[0064] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0065] It should also be noted that, in the description of the present invention, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A hybrid cavity laser device, characterized in that: The laser device includes a solid laser medium, a pump source, a first cavity mirror, a second cavity mirror, a folding mirror and a scraper mirror; The pump source is used to provide pump light for the solid laser medium; The solid laser medium is used to generate laser gain, the laser fast axis direction of the solid laser medium is the Y-axis direction, and the laser slow axis direction of the solid laser medium is the Z-axis direction; The first cavity mirror and the second cavity mirror are respectively arranged on both sides of the end face of the solid laser medium, and the first cavity mirror and the second cavity mirror constitute an optical resonant cavity for oscillating laser; The first cavity mirror and the second cavity mirror form an unstable cavity structure in the direction of the laser fast axis, and the first cavity mirror and the second cavity mirror form a stable cavity structure in the direction of the laser slow axis; The folding mirror is arranged between the solid laser medium and the second cavity mirror. The folding mirror is used to fold the cavity length in an unstable cavity structure and to increase the divergence angle of the laser beam in a stable cavity structure. The scraper mirror is arranged in the unstable cavity structure and is used to adjust the laser intensity and laser direction in the unstable cavity structure; The laser beam generated by the laser device is output through the second cavity mirror or the scraper mirror; The folding mirror is a plane folding mirror in the unstable cavity structure; The pump source is arranged on at least one end face, large face or side face of the solid laser medium; The cross section of the solid laser medium in the light transmission direction is irregular in shape; The solid laser medium is a slab laser medium, the activated ions in the slab laser medium include at least one of Nd, Yb, Ti, Pr, Cr, Tm or Ho, and / or the matrix material of the slab laser medium includes at least one of crystal, glass and ceramic; The unstable cavity structure is a coaxial unstable cavity structure; The scraper mirror is a perforated scraper mirror.

2. The laser device according to claim 1, characterized in that The folding mirror is a concave folding mirror or a convex folding mirror in the stable cavity structure.

3. The laser device according to claim 2, characterized in that The number of the folding mirror is one or more.

4. The laser device according to claim 1, wherein The first cavity mirror is a first concave mirror in the unstable cavity structure, and the second cavity mirror is a second concave mirror or a convex mirror in the unstable cavity structure; The first cavity mirror is a first concave mirror in the stable cavity structure, and the second cavity mirror is a plane mirror in the stable cavity structure.

5. The laser device according to claim 1, wherein The unstable cavity structure is a positive branch unstable cavity structure or a negative branch unstable cavity structure.

6. The laser device according to claim 5, characterized in that The unstable cavity structure is an off-axis unstable cavity structure.

7. The laser device according to claim 1, wherein The solid laser medium is a solid laser medium whose cross section in the light transmission direction is rectangular, trapezoidal or elliptical.

8. The laser device according to claim 1, wherein An included angle is set between the scraper mirror and the optical axis of the optical resonant cavity, and the scraper mirror is a solid scraper mirror.

9. The laser device according to claim 8, characterized in that The scraper mirror is a hole-opening scraper mirror, and the focal points of the first cavity mirror and the second cavity mirror coincide with the parallel light center axis of the hole-opening scraper mirror; The scraper mirror is a solid scraper mirror, and the solid scraper mirror is placed away from one side of the solid laser medium.

10. The laser device according to claim 8, characterized in that The surface of the scraper mirror close to the folding mirror is coated with a high laser reflection film for reflecting the output laser beam.

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