A compact slab-pulsed laser

Abstract

The application discloses a compact slab pulse laser, which comprises a laser oscillation cavity, the laser oscillation cavity is composed of a total reflection mirror (1), a bonded crystal (2) and an output mirror (5) arranged in sequence along the same axis, the two end faces (201) of the bonded crystal (2) are bevels, and the included angle between the bevels and the axis is a Brewster angle, and the bonded crystal (2) is provided with a pump light module on the side face. The application is a pulse laser based on the passive Q-switching principle, and the diode array pumps the bonded crystal; the structure is simple and compact, and the pulse laser with a peak power of hundreds to thousands of watts can be generated. In the application, the bonded crystal (2) is used as a working medium, the bonded crystal is integrated with a laser crystal (21) as a gain medium and a passive Q-switching crystal (22), so that the thermal effect of the working medium in the laser working can be reduced; meanwhile, the bonded crystal (2) is arranged in a slab structure, the contact area with a heat sink (4) is increased, the heat management requirement of the solid laser, especially the high-power solid laser, is effectively reduced, and it is an effective way to realize the compact high-power pulse laser.

Description

Technical Field

[0001] This invention relates to the field of solid-state lasers, and more particularly to a compact, high-power slab pulsed laser. Background Technology

[0002] Pulsed lasers have wide applications in medical, industrial, and military fields. However, these lasers suffer from problems such as large size and low power during operation.

[0003] In existing technologies, acousto-optic Q-switching is commonly used. This method requires adding a Q-switch within the resonant cavity and using an external power supply to drive it, making the system relatively complex and bulky. Furthermore, the increased cavity size makes the laser more susceptible to thermal lensing instability at high pump power. Additionally, the high cost of acousto-optic Q-switches limits the technology's application. While passive Q-switching is relatively simpler and can significantly simplify the system structure, the saturable absorber is typically a thin sheet structure, making effective heat dissipation difficult and hindering high-power operation. Currently, most passively Q-switched laser systems use low-power end-pumping. Moreover, the saturable absorber exhibits strong absorption of the fundamental frequency laser, and the thermal lensing effect is very pronounced, which is detrimental to stable laser output.

[0004] Existing pulsed lasers have complex structures and large volumes, and their power is limited by thermal effects, making it impossible to achieve high-power operation. Furthermore, the optical path is a straight optical path with the axis parallel, which will cause distortion. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a pulsed laser with compact structure, low thermal effect, high average power and high peak power.

[0006] To achieve the above effects, the basic concept of the present invention is: a compact slab pulsed laser, characterized in that it includes a laser oscillation cavity, which is composed of a total reflection mirror, a bonding crystal and an output mirror arranged sequentially along the same axis, wherein the two end faces of the bonding crystal are inclined, and a pump light module is provided on the side of the bonding crystal.

[0007] Furthermore, the two end faces of the bonded crystal form a Brewster angle with the axis.

[0008] Furthermore, the bonding crystal is formed by bonding a laser crystal near the total reflection mirror and a passively Q-switched crystal near the output mirror. The laser crystal is an Nd:YAG crystal, an Nd:YVO4 crystal, or a Yb:YAG crystal, and the passively Q-switched crystal is a Cr:YAG crystal.

[0009] Furthermore, the bonded crystal is a slab-shaped structure with a width greater than its thickness, and its upper and lower surfaces are large surfaces, with a heat sink provided on at least one of the large surfaces. The heat sink is a passive heat sink or an active heat sink, and the active heat sink includes water-cooled or semiconductor-cooled types.

[0010] Furthermore, the aperture of the passively Q-switched crystal is larger than the maximum spot size of the laser oscillation cavity.

[0011] Furthermore, the pump light module includes a laser diode array and a shaping coupling system. The pump light emitted by the laser diode is shaped and coupled by the shaping coupling system and then incident on the bonding crystal. The center wavelength of the pump light is 808nm, 885nm, 940nm or 976nm.

[0012] Furthermore, the side of the laser crystal adjacent to the pump light module is coated with a high-reflection coating that blocks pump light.

[0013] Furthermore, the total reflection mirror and the output mirror are plane mirrors or curved mirrors, the surface of the total reflection mirror is coated with a total reflection film, and the surface of the output mirror is coated with a partial reflection film.

[0014] Furthermore, the bonding crystal also includes a section of white YAG crystal, which is bonded to the end of the passively Q-switched crystal and / or the end of the laser crystal.

[0015] Furthermore, the length of the laser crystal is comparable to the length of the pump light irradiation area, and the length of the bonding crystal is comparable to the length of the cooling area of ​​the heat sink.

[0016] The technical solution of the present invention has the following beneficial effects:

[0017] 1. This invention is a pulsed laser based on the passive Q-switching principle of pumping bonded crystals. It uses bonded crystals as the working medium, and the bonded crystals are integrated with the laser crystal and the Q-switching crystal into one compact structure, which can reduce the thermal effect of the working medium during laser operation.

[0018] 2. At the same time, the bonding crystal is set as a strip structure to increase the contact area with the heat sink, which effectively reduces the thermal management requirements of solid-state lasers, especially high-power solid-state lasers, and thus can operate stably at high power.

[0019] 3. The two ends of the bonded crystal are set as bevels and form a Brewster angle with the axis. The laser is incident at a Brewster angle, which can minimize the amount of reflection when the laser enters the crystal and reduce the laser energy loss. At the same time, the beveled end faces make the laser propagate in a zigzag pattern inside the bonded crystal, increasing the optical path length and the number of reflections, and reducing birefringence and distortion caused by heat inside the crystal. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a specific embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the bonded crystal in a specific embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of a specific embodiment two of the present invention;

[0023] Figure 4 This is a schematic diagram of the specific structure of a third embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the pump structure in a specific embodiment three of the present invention.

[0025] Figure label:

[0026] Wherein 1-total reflection mirror; 2-bonding crystal; 3-pump optical module; 4-heat sink; 5-output mirror; 21-laser crystal; 22-passively Q-switched crystal; 23-white YAG crystal; 31-diode laser array; 32-shaping coupling system; 201-bonding crystal end face; 202-bonding crystal side face; 203-bonding crystal large facet (top). Detailed Implementation

[0027] The accompanying drawings illustrate a layer structure according to an embodiment of the present invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0028] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0031] A compact slab pulsed laser includes a laser oscillation cavity, which is composed of a total reflection mirror 1, a bonding crystal 2 and an output mirror 5 arranged sequentially along the optical axis. The two end faces 201 of the bonding crystal 2 are inclined planes and form a Brewster angle with the axis. A pump light module 3 is provided on the side of the bonding crystal.

[0032] This invention uses a bonded crystal 2 as the working medium because existing pulsed lasers suffer from large size and complex structure. Existing technologies commonly employ acousto-optic Q-switching, which requires adding a Q-switch within the laser resonant cavity and using an external power supply to drive it, resulting in a relatively complex and bulky system. Furthermore, the volume and power of the oscillating light are limited by the size of the acousto-optic crystal, preventing the achievement of high-power Q-switched output. Therefore, this invention uses a passive Q-switching crystal, combining the gain medium 21 and the passive Q-switching crystal 22 into a single bonded crystal 2 through a thermal bonding process. This allows for a more compact laser structure and reduces the thermal effects of the working medium during laser operation.

[0033] Furthermore, this invention sets the two end faces 201 of the bonding crystal 2 as inclined planes. This causes refraction at a certain angle when the laser is incident on the bonding crystal along its axis, resulting in a zigzag optical path transmission within the bonding crystal 2. The laser undergoes multiple reflections within the bonding crystal 2, compensating for first-order thermal focusing and thermally induced birefringence, effectively eliminating heat-induced birefringence and distortion within the crystal. Traditional lasers typically follow a straight optical path, and the internal thermally induced birefringence reduces laser quality. Moreover, the thermally induced birefringence and distortion become more severe with increasing power, limiting the improvement of laser power.

[0034] To obtain better laser quality, the present invention also sets the inclined surfaces of the two end faces 201 of the bonded crystal 2 to form a Brewster angle with the axis. The laser is incident at a Brewster angle, which can minimize the amount of reflected light when the laser enters the crystal and reduce laser energy loss.

[0035] Furthermore, to further reduce thermally induced birefringence and distortion, it is necessary to minimize the operating temperature of the bonded crystal. Therefore, increasing the heat dissipation area is considered. Specifically, the bonded crystal is configured as a lath structure, meaning the width of the bonded crystal is greater than its thickness. This increases the contact area with the heat sink, achieving better heat dissipation and effectively reducing the thermal management requirements of solid-state lasers, especially high-power solid-state lasers. As a result, it can operate stably and continuously at high power.

[0036] The bonding crystal in this embodiment of the invention comprises at least two parts. One part is a gain medium (laser crystal) that generates pump laser light, which is excited to generate laser light under the illumination of the pump source. The other part is a passively Q-switched crystal (saturable absorber). The passively Q-switched crystal has a large absorption effect on laser light, making the laser generation threshold very high. Inverted particles accumulate continuously until the radiation increases. The passively Q-switched crystal becomes transparent to laser light. Due to the sudden decrease in the threshold, a large number of inverted particles instantly return to the ground state, generating a giant laser pulse, thereby realizing the pulsed emission of laser light.

[0037] The gain medium 21 may include, but is not limited to, Nd:YAG crystal (neodymium-doped yttrium aluminum garnet crystal), Nd:YVO4 crystal (neodymium-doped yttrium vanadate crystal), or Yb:YAG crystal (ytterbium-doped yttrium aluminum garnet crystal), and the passive Q-switching crystal 22 may include, but is not limited to, Cr:YAG crystal (chromium-doped yttrium aluminum garnet crystal).

[0038] To achieve pulsed emission of all laser beams, the aperture of the passively Q-switched crystal 22 must be larger than the maximum spot size of the laser oscillator cavity. Otherwise, some laser beams will not be absorbed by the passively Q-switched crystal, making it impossible to achieve pulsed emission of all laser beams.

[0039] The pump optical module 3 of this invention employs a laser diode array, with a center wavelength of 808nm, 885nm, 940nm, or 976nm. The selection of different wavelengths is based on the absorption and excitation characteristics of the gain medium 21 for different wavelengths. Depending on the operating conditions, different wavelength laser diode arrays can be selected when using different gain media.

[0040] To achieve stable continuous operation at high power, it is necessary to improve the heat dissipation of the laser and reduce the adverse effects of thermal effects. Therefore, this invention considers setting the bonding crystal 2 as a slab-shaped structure with a width greater than its thickness, with its upper and lower surfaces as large surfaces 203. A heat sink 4 is provided on at least one of the large surfaces 203, which is in contact with the surface of the bonding crystal. That is, the heat sink can be set on the upper surface of the slab-shaped bonding crystal or on the lower surface of the bonding crystal. Furthermore, if the pump light module is set on the side of the bonding crystal, heat sinks can be set on both the upper and lower surfaces, resulting in better cooling. The heat sink can be a passive heat sink or an active heat sink. The passive heat sink can be made of metal materials with good thermal conductivity, such as copper or silver. The active heat sink can be an active water-cooled heat sink or a semiconductor-cooled heat sink. Since water has a very high specific heat capacity, this invention preferably uses a microchannel water-cooled heat sink, which can quickly remove heat from the bonding crystal through the circulation of cooling water, thereby improving the quality of laser generation.

[0041] For the total reflection mirror and output mirror at both ends of the laser oscillation cavity, either a plane mirror or a curved mirror can be selected according to different operational needs. The surface of the total reflection mirror is coated with a total reflection film, while the surface of the output mirror is coated with a partial reflection film.

[0042] To effectively cool the passively Q-switched crystal, the bonded crystal also includes a section of white YAG crystal 23 (undoped YAG crystal), which is bonded to the outside of the passively Q-switched crystal. The Cr:YAG crystal acts as a saturable absorber for Q-switching the laser, while the white YAG crystal conducts heat away from the passively Q-switched crystal, reducing the overall thermal effect of the bonded crystal. This design tightly integrates the laser crystal and the Q-switching crystal, making the entire resonant cavity structure more compact. Simultaneously, the bonded crystals can be water-cooled in a water-cooling system, overcoming the limitation of previous passively Q-switched systems that could not cool the passively Q-switched crystal 22 (saturable absorber) and therefore could not operate at high pump power. Furthermore, the white YAG crystal 23 bonded to the end prevents the high-temperature end face of the Cr:YAG crystal (because saturable absorbers have significant laser absorption) from being exposed to air, thus preventing poor heat dissipation and increased thermal effects. Similarly, a white YAG crystal can also be bonded to the end of the laser crystal to further aid in heat dissipation.

[0043] This invention also sets the length of the laser crystal 21 to be approximately equal to the length of the irradiation area of ​​the pump light module 3. This configuration of the pump light source ensures that the laser crystal is fully irradiated, making full use of the laser crystal and avoiding unnecessary waste caused by unirradiated areas. To further reduce thermal effects, the length of the bonding crystal 2 is made approximately equal to the length of the cooling area of ​​the heat sink 4, ensuring that the entire bonding crystal is cooled by the heat sink.

[0044] The above-described scheme is the basic structure of this invention. In different application scenarios, the different component combinations of this invention can be configured and adjusted in different ways. The technical solution of this invention will be further described below with reference to different embodiments.

[0045] Example 1, as Figure 1 and Figure 2 As shown, the first embodiment of the present invention provides a compact high-power pulsed laser, including: a pump light module 3, a bonding crystal 2 (including a laser crystal 21 and a passively Q-switched crystal 22), an output mirror 5, and a total reflection mirror 1. The total reflection mirror 1, the bonding crystal 2, and the output mirror 5 are arranged sequentially along the optical axis from left to right to form a laser resonant cavity.

[0046] The bonding crystal 2 includes a laser crystal 21 and a passively Q-switched crystal 22. In this embodiment, the laser crystal 21 is an Nd:YAG crystal (neodymium-doped yttrium aluminum garnet crystal), and the passively Q-switched crystal is a Cr:YAG crystal (chromium-doped yttrium aluminum garnet crystal). The bonding crystal 2 is a trapezoidal crystal with both end faces 201 chamfered at Brewster angles. The laser crystal 21 can absorb pump light, generating intracavity oscillating laser light, thus creating conditions for output laser pulses. The saturable absorption of the passively Q-switched crystal 22 is used to modulate the laser light. When the incident light intensity increases to a certain level, the inverted particles of the saturable absorber are consumed, thereby generating a Q-switched pulse output in the resonant cavity. The laser crystal 21 is located between two cavity mirrors. One side 203 of its large surface is coated with a high-reflection coating for pump light, serving as the incident surface to absorb pump light. The other side is coated with a pump light reflective coating to increase the absorption length. This side is welded to the heat sink 4, which is a microchannel water-cooled heat sink to improve heat dissipation efficiency.

[0047] The pump light module 3 is a laser diode array located on one side of the bonding crystal 2, serving as a continuous laser pump source. The laser pump source provides excitation energy to the laser crystal 21. The center wavelength of the pump light should match the absorption spectrum of the bonding crystal 21 to achieve better absorption and higher optical efficiency. In this embodiment, the center wavelength of the LD pump light is 808 nm, and the power can reach hundreds of watts to tens of thousands of watts.

[0048] The beam shaping coupling system 32 is a rectangular quartz waveguide that shapes the pump light emitted by the diode laser array 31 into a uniformly distributed rectangular spot. The light is incident from a large surface 203 of the lath-shaped bonding crystal 2 and is absorbed twice by reflection from the bonding surface.

[0049] The aforementioned cavity mirrors include: the total reflection mirror 1 is a plane mirror coated with a high-reflectivity film for oscillating light; the output mirror 5 is a plane mirror, with a partial transmittance film for oscillating light coated on the side facing the bonding crystal 2, and a high transmittance film coated on the other side, used to couple the output cavity laser.

[0050] The above embodiments, without altering the internal structure and optical component configuration of the laser, and while meeting the bonding crystal damage threshold, increase crystal heat dissipation and reduce the thermal effect of the working medium during laser operation by employing side microchannel active cooling and crystal bonding. Furthermore, the application of the bonding crystal 2 offers the following advantages: a compact laser structure and improved beam quality.

[0051] Example 2, as Figure 3 As shown:

[0052] The end-face pumped strip self-Q-switching method is adopted, including: diode laser array 13, laser crystal 21, passively Q-switched crystal 22, output mirror 5, total reflection mirror 1, and shaping coupling system 32;

[0053] The total reflection mirror 1, the bonding crystal 2, and the output mirror 5 are placed along the optical axis from left to right to form a laser resonant cavity.

[0054] The bonded crystal 2 includes a laser crystal 21 and a passively Q-switched crystal 22. In this embodiment, the laser crystal 21 is an Nd:YAG slab crystal, and the passively Q-switched crystal 22 is a Cr:YAG crystal. To increase heat dissipation and withstand higher pump power, a section of white YAG crystal 23 is bonded to the outside of the Cr:YAG crystal to conduct heat away from the passively Q-switched crystal, thereby improving the heat dissipation performance of the bonded crystal 2.

[0055] The bonding crystal 2 is located between the two cavity mirrors, with each end face cut at a 45° angle (the calculated Brewster angle). Both end faces are coated with a bicolor film that provides high anti-reflection laser light against the pump beam. The laser beam is incident on the bonding crystal 2 at a certain angle and is continuously totally reflected inside the crystal, propagating in a zigzag optical path and compensating for thermal distortion and thermal depolarization caused by the pump.

[0056] The semiconductor laser pump module 31 is a laser diode array located on both sides of the aforementioned bonding crystal 2, as shown in the figure. Figure 3 The LD pump light serves as a continuous laser pump source. The pump source provides excitation energy to the laser crystal, and the center wavelength of the pump light should match the absorption spectrum of the laser crystal (2), which is the laser crystal 21, to achieve a better absorption rate and higher optical efficiency. In this embodiment, the center wavelength of the LD pump light is 808 nm, and the power can reach hundreds of watts to kilowatts.

[0057] The beam shaping coupling system 32 shapes the pump light emitted by the semiconductor laser pump module 31 into a uniformly distributed rectangular spot. The pump light is incident perpendicularly from both ends of the two end faces 201 of the slab-shaped bonding crystal 2, and after being reflected at 45° from both end faces, it is transmitted along the length of the slab and absorbed by the laser crystal 21.

[0058] The aforementioned cavity mirrors include: a total reflection mirror 1, which is a plane mirror coated with a high-reflectivity film for oscillating light; and an output mirror 5, which is a plane mirror with a partially transmittance film for oscillating light coated on the side facing the laser crystal and a high-transmittance film coated on the other side, used to couple the laser within the output cavity. When the incident light intensity increases to a certain level, the passively Q-switched crystal 22 will be bleached, thereby generating a self-Q-switched pulse output within the resonant cavity.

[0059] After adopting the above technical solution, the pump light is injected from both ends of the bonding crystal. Heat sinks 4 can be set on both large surfaces 203 of the bonding crystal 2. The heat sinks 4 adopt active water-cooled micro-channel circulation, which has a better cooling and heat dissipation effect, enabling it to reach higher power. Due to the further reduction of thermal effect, it can work stably and continuously at higher power.

[0060] Example 3, as Figure 4 and Figure 5 As shown,

[0061] A self-Q-switched laser employing edge-pumped slabs includes: a pump source, a diode laser array 3, an LD edge-pumped light shaping and coupling system 32, a bonding crystal 2, an output mirror 5, and a total reflection mirror 1;

[0062] The total reflection mirror 1, bonding crystal 2, and output mirror 5 are placed along the optical axis in order from left to right to form a laser resonant cavity.

[0063] The laser crystal 21, acting as a gain medium, absorbs the pump light, thereby achieving population inversion and generating laser light. In this embodiment, the laser crystal 21 is an Nd:YAG slab-shaped crystal with a white YAG crystal 23 bonded to one end and a passively Q-switched crystal 22 bonded to the other end. The laser crystal 21 is located between the two cavity mirrors. In this embodiment, an edge-pumping method is used, providing high-brightness pump light while also ensuring a more uniform distribution of the pump light within the slab.

[0064] In this embodiment, both ends of the laser crystal 21 and the passively Q-switched crystal 22 are bonded with white YAG crystals 23. This is because in this embodiment, the pump light is simultaneously incident from both sides of the bonded crystals, generating higher power and requiring better heat dissipation. Therefore, white YAG crystals are placed at both ends of the laser crystal 21 and the passively Q-switched crystal to aid heat conduction. The white YAG crystals at the ends of the laser crystals conduct heat away from the laser crystal 21 and the passively Q-switched crystal 22, achieving a better cooling effect.

[0065] The pump source diode laser array 31 is located on both sides of the laser crystal 21, as shown in the figure. Figure 5To achieve high optical-to-optical efficiency, good absorption efficiency of the pump light is essential. Therefore, a pump center wavelength that matches the laser crystal should be selected. In this embodiment, a continuous laser pump source is used, with a LD pump light center wavelength of 808 nm and a power ranging from hundreds of watts to kilowatts.

[0066] The pump light shaping coupling system 32 shapes the pump light emitted from the diode laser pump module 31 into a uniformly distributed rectangular spot. The pump light is incident perpendicularly from both sides 202 of the bonding crystal, propagates along the width of the slab, and is absorbed by the laser crystal 21. The passively Q-switched crystal 22, bonded to one side of the laser crystal 21 and modulating the laser, is Cr:YAG. When the incident light intensity increases to a certain level, the passively Q-switched crystal 22 is bleached, thereby generating a Q-switched pulse output in the resonant cavity.

[0067] The aforementioned cavity mirrors include: the total reflection mirror 1 is a plane mirror coated with a high-reflectivity film for oscillating light; the output mirror 5 is a plane mirror coated with a partial transmittance film for oscillating light on the side facing the laser crystal.

[0068] Using the above scheme, heat sinks 4 can also be simultaneously placed on both large surfaces 203 of the bonding crystal 2 to reduce the thermal effect. At the same time, the method of simultaneously injecting pump light from both sides can achieve a higher operating power. In addition, the white YAG crystals 23 bonded to both ends of the bonding crystal further improve the heat dissipation effect. Moreover, the two end faces of the bonding crystal 2 are chamfered at Bruce angles, and the laser undergoes continuous total internal reflection in a zigzag pattern inside the bonding crystal, which reduces the birefringence and distortion caused by heat within the crystal and can compensate for first-order thermal focusing.

[0069] The above embodiments, without altering the internal structure and optical component configuration of the laser, and while meeting the bonding crystal damage threshold, increase crystal heat dissipation and reduce the thermal effect of the working medium during laser operation by employing side microchannel active cooling and crystal bonding. The use of bonded crystals makes the laser structure more compact.

[0070] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A compact slab pulsed laser, characterized in that, It includes a laser oscillation cavity, which is composed of a total reflection mirror (1), a bonding crystal (2) and an output mirror (5) arranged sequentially along the same axis. The two ends of the bonding crystal (2) are inclined, and a pump light module that can illuminate the bonding crystal is provided on the side of the bonding crystal (2). The bonding crystal (2) is formed by bonding a laser crystal (21) near the total reflection mirror and a passive Q-switching crystal (22) near the output mirror. The laser crystal (21) is an Nd:YAG crystal, an Nd:YVO4 crystal or a Yb:YAG crystal, and the passive Q-switching crystal (22) is a Cr:YAG crystal. The bonding crystal (2) is a strip-shaped structure with a width greater than its thickness. Its upper and lower surfaces are bonding crystal large surfaces (203), and a heat sink (4) is provided on at least one large surface (203). The heat sink (4) is a passive heat sink or an active heat sink. The active heat sink includes a water-cooled heat sink or a semiconductor cooling heat sink. The aperture of the passively Q-switched crystal (22) is larger than the maximum spot size of the laser oscillation cavity; The bonding crystal also includes a white YAG crystal (23), which is bonded to the end of the passively Q-switched crystal (22) and / or the end of the laser crystal (21); The length of the laser crystal (21) is comparable to the length of the pump light irradiation area, and the length of the bonding crystal (2) is comparable to the length of the cooling area of ​​the heat sink (4).

2. The compact slab pulsed laser according to claim 1, characterized in that, The two end faces of the bonded crystal (2) form a Brewster angle with the axis.

3. The compact slab pulsed laser according to claim 1, characterized in that, The pump light module (3) includes a laser diode array (31) and a shaping coupling system (32). The pump light emitted by the laser diode array (31) is shaped and coupled by the shaping coupling system (32) and then incident on the bonding crystal (2). The center wavelength of the pump light is 808nm, 885nm, 940nm or 976nm.

4. A compact slab pulsed laser according to claim 1, characterized in that, The bonding crystal (2) is coated with a high-reflection coating on the side adjacent to the pump light module (3).

5. A compact slab pulsed laser according to claim 1, characterized in that, The total reflection mirror (1) and the output mirror (5) are plane mirrors or curved mirrors. The surface of the total reflection mirror (1) is coated with a total reflection film, and the surface of the output mirror (5) is coated with a partial reflection film.

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