Self-Q-switching composite laser element and preparation method and application thereof

Abstract

The invention discloses a self-Q-switching composite laser element and a preparation method and application thereof, the self-Q-switching composite laser element comprises a matrix, the matrix is doped garnet crystal and / or ceramic, the composition of the garnet crystal and / or ceramic is A3B5O12, and the doped element is Yb and Er, or Er, or Nd; the first bonding body is bonded at the front end of the substrate, and the first bonding body is MgAl2O4 crystal and / or ceramic; and the second bonding body is bonded at the rear end of the substrate, and the second bonding body is Co: MgAl2O4 crystal and / or ceramic. The self-Q-switching composite laser element can improve the thermal load of a laser material, shorten the cavity length of the laser resonant cavity, improve the effect of a laser, and solve the problems of split structure of a Q-switching laser system and waste heat accumulation of a laser gain medium.

Description

Technical Field

[0001] The invention belongs to the technical field of laser element preparation, and in particular relates to a self-Q-switched composite laser element and a preparation method thereof, and also relates to the application of the self-Q-switched composite laser element in a self-Q-switched laser. Background Art

[0002] Laser Q-switching technology is a method to increase the peak power of lasers by compressing the laser energy into extremely narrow pulses. This technology is based on a special optical element - the Q switch, which can quickly change the Q value of the laser resonant cavity at a specific moment, thereby controlling the oscillation and output of the laser. The core principle of Q-switching technology is that after the pumping starts, the laser oscillation is stopped by reducing the Q value of the resonant cavity, so that the degree of particle number inversion in the working material continues to accumulate. When it accumulates to a certain extent, the Q value is suddenly increased, so that the laser oscillation occurs rapidly, and the accumulated energy is released in a very short time, forming a laser output with high peak power and narrow pulse width.

[0003] The methods for implementing laser Q-switching technology are mainly divided into active Q-switching and passive Q-switching. Among them, active Q-switching technology is to dynamically adjust the Q value by actively introducing a modulator in the laser resonant cavity. Passive Q-switching technology uses the saturation absorption effect of nonlinear optical materials to achieve rapid Q-switching. In passive Q-switching, no external trigger is required, but the characteristics of the optical material itself are relied upon to achieve pulse generation. Passive Q-switching technology is favored for its simplicity, low cost and high stability.

[0004] In passive Q-switching technology, Co:MgAl2O4 has excellent saturation absorption characteristics in the range of 1.2 to 1.6μm, and is the preferred material for passive Q-switching of solid lasers in this band. Since the laser resonant cavity is usually constructed with a separate structure of laser gain material and saturated absorber when passively Q-switched laser output is used, this method not only increases the difficulty of heat conduction between the laser gain medium and the saturable absorber, but also increases the length of the laser resonant cavity, thereby increasing the loss in the laser cavity. On the other hand, as the laser power increases, the waste heat of the laser gain material is higher, which becomes the main reason for the deterioration of the laser beam quality. How to quickly export the heat has become the first problem that needs to be solved in the development of high peak power lasers. Summary of the invention

[0005] In view of this, the primary purpose of the present invention is to provide a self-Q-switched composite laser element, which can improve the thermal load of the laser material, shorten the cavity length of the laser resonant cavity, improve the effect of the laser, and solve the problems of discrete structure of the Q-switched laser system and waste heat accumulation of the laser gain medium.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A first aspect of the present invention provides a self-Q-switched composite laser element, the self-Q-switched composite laser element comprising:

[0008] The matrix is ​​a doped garnet crystal and / or ceramic, and the composition of the garnet crystal and / or ceramic is A3B5O 12 , wherein A is any one or two of Y, Lu, Gd, and Sc, and B is any one or two of Al and Ga; and the doping elements are Yb and Er, or Er, or Nd;

[0009] A first bonding body bonded to the front end of the substrate, wherein the first bonding body is a MgAl2O4 crystal and / or a ceramic;

[0010] And a second bonding body bonded to the rear end of the substrate, wherein the second bonding body is Co:MgAl2O4 crystal and / or ceramic.

[0011] In the present invention, MgAl2O4 crystal and / or ceramic and Co:MgAl2O4 crystal and / or ceramic are bonded to the front and rear ends of the doped garnet crystal and / or ceramic respectively to form an integrated composite laser element, which can not only improve the heat load of the laser material, solve the problem of discrete structure of the Q-switched laser system and waste heat accumulation of the laser gain medium, but also shorten the cavity length of the laser resonant cavity and improve the efficiency of the laser.

[0012] In the present invention, the composition of the doped garnet crystal and / or ceramic is Yb, Er / Er / Nd: A3B5O 12 Specifically, it can be doped with Er alone, or doped with Nd alone, or doped with Y and Er. The composition is A3B5O 12 Garnet is a cubic mineral material well known in the art, wherein A and B represent different cations, and the A cation forms an octahedral coordination with the oxygen atom, which means that there are eight oxygen atoms around the A cation. This coordination mode plays a key role in the crystal structure, thus determining the symmetry and stability of the crystal. At the same time, the B cation exists in the form of an octahedron, which means that there are six oxygen atoms around the B cation, forming a regular octahedral structure. A and B can both be cations well known in the art, for example, in some specific embodiments of the present invention, A is Y, or Lu, or Gd x Sc 1-x , or Y x Sc 1-x , or Lu x Sc 1-x ; B is Al, or Ga, or Al y Ga 1-y; wherein 0≤x, y≤1. Examples of garnet crystals and / or ceramics that can be specifically mentioned in the present invention include gadolinium gallium garnet (Gd3Ga5O 12 ) or yttrium aluminum garnet (Y3Al5O 12 ) or gadolinium-scandium-gallium garnet (Gd3Sc2Ga3O 12 ) or gadolinium scandium aluminum garnet (Gd3Sc2Al3O 12 ), but not limited thereto. In addition, it is understood that the concentration of the doping element in the garnet crystal and / or ceramic is a conventional concentration in the art and is not specifically limited here.

[0013] In the present invention, the self-Q-switched composite laser element can be cut into a conventional element shape in the art as required. In some specific embodiments of the present invention, it is a regular quadrangular prism or a cylindrical shape, but is not limited thereto. Figure 1 FIG. 4 shows a schematic structural diagram of a self-Q-switched composite laser element in a specific implementation manner.

[0014] It is understandable that the specific dimensions of the substrate, the first bonding body, and the second bonding body of the self-Q-switched composite laser element can be designed as needed, but it is necessary to ensure that the cross-sectional areas of the substrate, the first bonding body, and the second bonding body are equal, that is, the dimensions of the bonding interfaces between the substrate and the first bonding body and the second bonding body are the same. And, preferably, the length of the substrate is greater than the lengths of the first bonding body and the second bonding body. For example, in some specific implementation cases of the present invention, the dimensions of the substrate are (4-10) mm×(4-10) mm×(8-25) mm, and the dimensions of the first bonding body and the second bonding body are (4-10) mm×(4-10) mm×(2.5-5) mm, respectively.

[0015] A second aspect of the present invention provides a method for preparing the self-Q-switched composite laser element as described above, comprising the following steps:

[0016] preparing a substrate, a first bonding body and a second bonding body respectively;

[0017] The first bonding body is bonded to the front end surface of the substrate, and the second bonding body is bonded to the rear end surface of the substrate to obtain the self-Q-switched composite laser element.

[0018] In the present invention, the substrate, the first bonding body and the second bonding body can be prepared by processes well known in the art without particular limitation. For example, in some specific embodiments of the present invention, the substrate, the first bonding body and the second bonding body are crystals, and conventional crystal preparation methods such as the Czochralski method can be used to grow them. In other specific embodiments of the present invention, the substrate, the first bonding body and the second bonding body are ceramics, and conventional ceramic preparation methods such as high-temperature sintering can be used to prepare them.

[0019] In a further embodiment, the bonding described in the present invention can be achieved by bonding methods well known in the art, such as optically transparent chemical adhesive bonding, low melting point metal bonding, diffusion bonding, optical adhesive bonding, etc. In some preferred embodiments of the present invention, the bonding is achieved by an optical adhesive bonding process, and the optical adhesive bonding process includes the following steps:

[0020] Polishing the front end face and the rear end face of the substrate, and the bonding surfaces of the first bonding body and the second bonding body respectively to a photoresist-able condition;

[0021] Cleaning the polished surface and irradiating the cleaned surface with ultraviolet light, and then photobonding the front end surface of the first bonding body and the rear end surface of the substrate, respectively;

[0022] The composite component after optical bonding is subjected to high temperature sintering and annealing in sequence to obtain a self-Q-switched composite laser component.

[0023] The photoresist conditions described in this article refer to surface flatness ≥λ / 10@633nm, roughness Ra ≥0.5nm, and optical defects of level 0.

[0024] The cleaning described in this article refers to cleaning the polished surface by using chemical reagents such as H3PO4, H2SO4 or H2SO4+H2O2 to achieve the purpose of removing the polishing powder or polishing liquid remaining on the surface.

[0025] Furthermore, in this paper, the cleaned surface is irradiated with ultraviolet light to increase the number of dangling bonds on the surface. In some specific embodiments of the present invention, excimer laser irradiation with a wavelength of 193 nm and an energy density of 3 to 3.6 J / cm 2 , irradiation time is 5 to 15 minutes. The specific irradiation parameters vary according to the crystal or ceramic, are not limited to the conditions in this article, and can be determined based on methods known in the art.

[0026] Furthermore, a certain pressure can be applied as needed during the optical adhesive bonding, and generally the larger the bonding surface, the greater the pressure required. In some specific embodiments of the present invention, the pressure is preferably 0.5-1 MPa, for example, 0.5, 0.6, 0.8, 0.9, 1.0 MPa, etc.

[0027] In the present invention, the high temperature sintering temperature is 1400-1600°C, the sintering time is 7-10 days, and a pressure of 0.5-1 MPa is applied at the same time; the annealing temperature is preferably 1200°C, and the annealing time is not less than 3 days.

[0028] The third aspect of the present invention provides a self-Q-switched device, which is formed by polishing the two light-passing end faces of the self-Q-switched composite laser element described above and then coating the polished two light-passing end faces with a dielectric film or without coating.

[0029] The fourth aspect of the present invention provides a self-Q-switched laser, which includes the self-Q-switched device described above. It is understandable that the self-Q-switched laser also includes other common structural elements. For example, in a typical embodiment of the present invention, a composition of a self-Q-switched laser is provided, which includes a laser pump source, a coupling system, a focusing system, an input mirror, the self-Q-switched device described in the present invention, and an output mirror in sequence along the optical path. These structural elements can be adjusted or selected according to the needs of those skilled in the art, and will not be specifically described one by one here.

[0030] Beneficial effects of the present invention:

[0031] The self-Q-switched composite laser element provided in the present invention, Co:MgAl2O4 crystal / ceramic not only has the function of Q-switching, but also can play a role similar to that of a heat sink like MgAl2O4 crystal / ceramic, which can effectively reduce and alleviate the gradient relationship between the center temperature and the side temperature of the crystal, and reduce the thermal lens effect induced by the change of the refractive index due to the deformation of the end face; and because both MgAl2O4 and garnet series matrix materials are cubic structures, and the thermal conductivity of the former is higher than that of the latter, the self-Q-switched composite laser element in the present invention can improve the thermal load of the laser material, solve the problem of discrete structure of the Q-switched laser system and the waste heat accumulation of the laser gain medium. In addition, the integrated composite laser element can also shorten the cavity length of the laser resonant cavity and improve the efficiency of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of a self-Q-switched composite laser element in a preferred embodiment of the present invention.

[0033] Figure 2 FIG. 1 is a diagram of the laser output optical path of a self-Q-switched device in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In addition, unless otherwise specified, methods that do not specifically record conditions or steps are conventional methods, and the reagents and materials used can be obtained from commercial sources.

[0036] Example 1

[0037] This embodiment provides a self-Q-switched composite laser element, whose matrix is ​​Yb, Er: Y3Al5O 12 The front end of the substrate is bonded with a MgAl2O4 crystal, and the rear end of the substrate is bonded with a Co:MgAl2O4 crystal.

[0038] The self-Q-switched composite laser element in this embodiment is prepared by the following method:

[0039] (1) Bulk Yb,Er:Y3Al5O was grown by Czochralski method 12 , MgAl2O4 and Co:MgAl2O4 crystal blanks.

[0040] (2) Combine Yb,Er:Y3Al5O 12 The crystal blank was cut into small pieces of 6mm×6mm×11mm, and the front and rear end faces of 6mm×6mm were polished to the following indicators: size 6mm×6mm×10mm, flatness ≥λ / 10@633nm, roughness Ra≥0.5nm, optical defects of level 0, and the polished front and rear end faces were recorded as F1 and F2 respectively.

[0041] (3) MgAl2O4 and Co:MgAl2O4 crystals were cut into 6 mm × 6 mm × 2.5 mm blocks, and any 6 mm × 6 mm end faces of the MgAl2O4 and Co:MgAl2O4 crystals were polished, denoted as F1' and F2', respectively, until they reached the conditions for photoresist, i.e., flatness ≥ λ / 10@633 nm, roughness Ra ≥ 0.5 nm, and optical defects were level 0.

[0042] (4) Combine Yb,Er:Y3Al5O 12, MgAl2O4 and Co:MgAl2O4 crystals were placed in beakers containing concentrated H3PO4 respectively, and then heated to 200°C in an oil bath. After maintaining a constant temperature of 200°C for 10 min, they were taken out, rinsed with distilled water and dried.

[0043] (5) Laser energy density of 3.50 J / cm 2 The 193nm excimer laser was irradiated on the F1 and F2 surfaces for 10min, and on the F1' and F2' surfaces for 8min, and then Yb, Er: Y3Al5O 12 The F1 and F2 faces of the crystal were photobonded with the F1' face of the MgAl2O4 crystal and the F2' face of the Co:MgAl2O4 crystal respectively.

[0044] (6) The composite component MgAl2O4 / Yb,Er:Y3Al5O 12 / Co:MgAl2O4 is placed in a high temperature furnace and sintered at 1500°C for 7 days with a sintering pressure of 0.6MPa; the sintered composite laser crystal is annealed at 1200°C for 3 days to obtain a self-Q-switched composite laser element.

[0045] Example 2

[0046] This embodiment provides another self-Q-switched composite laser element, whose matrix is ​​Yb, Er: Y3Al5O 12 Ceramic, the front end of the substrate is bonded with MgAl2O4 ceramic, and the rear end of the substrate is bonded with Co:MgAl2O4 ceramic.

[0047] The self-Q-switched composite laser element in this embodiment is prepared by the following method:

[0048] (1) Obtaining bulk Yb,Er:Y3Al5O by high temperature sintering 12 , MgAl2O4 and Co:MgAl2O4 ceramic blanks.

[0049] (2) Combine Yb,Er:Y3Al5O 12 The ceramic blank was cut into small pieces of 4mm×4mm×9mm, and the front and rear end faces of 4mm×4mm were polished to the following indicators: size 4mm×4mm×8mm, flatness ≥λ / 10@633nm, roughness Ra≥0.5nm, and optical defect level 0; the polished front and rear end faces were recorded as F1 and F2, respectively.

[0050] (3) MgAl2O4 and Co:MgAl2O4 ceramics were also cut into 4 mm × 4 mm × 2.5 mm squares. One 4 mm × 4 mm end face of the MgAl2O4 and Co:MgAl2O4 ceramics was polished, denoted as F1' and F2', respectively, until the conditions for photoresist were met, i.e., flatness ≥ λ / 10@633 nm, roughness Ra ≥ 0.5 nm, and optical defects were level 0.

[0051] (4) Combine Yb,Er:Y3Al5O 12 , MgAl2O4 and Co:MgAl2O4 ceramics were placed in beakers filled with concentrated H2SO4, then heated to 250°C in an oil bath, kept constant at 250°C for 10 min, taken out, rinsed with distilled water and dried.

[0052] (5) Laser energy density of 3.00 J / cm 2 The 193nm excimer laser was irradiated on the F1 and F2 surfaces for 10min, and on the F1' and F2' surfaces for 8min, and then Yb, Er: Y3Al5O 12 The F1 and F2 surfaces of the ceramic are lightly bonded to the F1' surface of the MgAl2O4 ceramic and the F2' surface of the Co:MgAl2O4 ceramic respectively.

[0053] (6) The composite component MgAl2O4 / Yb,Er:Y3Al5O 12 / Co:MgAl2O4 is placed in a high temperature furnace and sintered at 1400°C for 7 days with a sintering pressure of 0.6MPa; the sintered composite ceramic is annealed at 1200°C for 3 days to obtain a self-Q-switched composite laser element.

[0054] Example 3

[0055] This embodiment provides another self-Q-switched composite laser element, whose matrix is ​​Yb, Er: Y3Al5O 12 Crystal, the front end of the substrate is bonded with MgAl2O4 ceramic, and the rear end of the substrate is bonded with Co:MgAl2O4 ceramic.

[0056] The self-Q-switched composite laser element in this embodiment is prepared by the following method:

[0057] (1) Bulk Yb,Er:Y3Al5O was grown by Czochralski method 12 Crystal blanks are sintered at high temperature to obtain bulk MgAl2O4 and Co:MgAl2O4 ceramic blanks.

[0058] (2) Combine Yb,Er:Y3Al5O 12The crystal blank was cut into small pieces of 8mm×8mm×15mm, and the front and rear end faces of 8mm×8mm were polished to the following indicators: size 8mm×8mm×14mm, flatness ≥λ / 10@633nm, roughness Ra≥0.5nm, and optical defects of level 0; the polished front and rear end faces were recorded as F1 and F2, respectively.

[0059] (3) MgAl2O4 and Co:MgAl2O4 ceramics were also cut into 8 mm × 8 mm × 4 mm blocks. One 8 mm × 8 mm end face of the MgAl2O4 and Co:MgAl2O4 ceramics was polished, denoted as F1' and F2', respectively, until the conditions for photoresist were met, i.e., flatness ≥ λ / 10@633 nm, roughness Ra ≥ 0.5 nm, and optical defects were level 0.

[0060] (4) Combine Yb,Er:Y3Al5O 12 The crystal, MgAl2O4 and Co:MgAl2O4 ceramics were placed in beakers containing concentrated H3PO4, respectively, and then heated to 220°C in an oil bath. After maintaining the temperature at 220°C for 8 min, they were taken out, rinsed with distilled water and dried.

[0061] (5) Laser energy density of 3.30 J / cm 2 The 193nm excimer laser was irradiated on the F1 and F2 surfaces for 13min and on the F1' and F2' surfaces for 6min, and then Yb, Er: Y3Al5O 12 The F1 and F2 faces of the crystal were photobonded with the F1' face of the MgAl2O4 ceramic and the F2' face of the Co:MgAl2O4 ceramic respectively.

[0062] (6) The components MgAl2O4 / Yb, Er:Y3Al5O 12 / Co:MgAl2O4 is placed in a high temperature furnace and sintered at 1600°C for 7 days with a sintering pressure of 0.8MPa; the sintered composite element is annealed at 1200°C for 5 days to obtain a self-Q-switched composite laser element.

[0063] Example 4

[0064] This embodiment provides another self-Q-switched composite laser element, whose matrix is ​​Yb, Er: Gd3Sc2Ga3O 12 The front end of the substrate is bonded with a MgAl2O4 crystal, and the rear end of the substrate is bonded with a Co:MgAl2O4 crystal.

[0065] The self-Q-switched composite laser element in this embodiment is prepared by the following method:

[0066] (1) Bulk Yb,Er:Gd3Sc2Ga3O was grown by Czochralski method 12 , MgAl2O4 and Co:MgAl2O4 crystal blanks.

[0067] (2) Combine Yb,Er:Gd3Sc2Ga3O 12 The crystal blank was cut into small pieces of 10mm×10mm×25mm, and the front and rear end faces of 10mm×10mm were polished to the following indicators: size 10mm×10mm×24mm, flatness ≥λ / 10@633nm, roughness Ra≥0.5nm, optical defects of level 0, and the polished front and rear end faces were recorded as F1 and F2, respectively.

[0068] (3) MgAl2O4 and Co:MgAl2O4 crystals were cut into 10 mm × 10 mm × 5 mm blocks, and any 10 mm × 10 mm end faces of the MgAl2O4 and Co:MgAl2O4 crystals were polished, denoted as F1' and F2', respectively, until they reached the conditions for photoresist, i.e., flatness ≥ λ / 10@633 nm, roughness Ra ≥ 0.5 nm, and optical defects were level 0.

[0069] (4) Combine Yb,Er:Gd3Sc2Ga3O 12 , MgAl2O4 and Co:MgAl2O4 crystals were placed in beakers filled with concentrated H2SO4, then heated to 280°C in an oil bath, kept constant at 280°C for 8 min, taken out, rinsed with distilled water and dried.

[0070] (5) Laser energy density of 3.20 J / cm 2 The 193nm excimer laser was irradiated on the F1 and F2 surfaces for 15min, and on the F1' and F2' surfaces for 12min, and then Yb, Er:Gd3Sc2Ga3O 12 The F1 and F2 faces of the crystal were photobonded with the F1' face of the MgAl2O4 crystal and the F2' face of the Co:MgAl2O4 crystal respectively.

[0071] (6) Place the optically bonded component MgAl2O4 / Yb,Er:Gd3Sc2Ga3O 12 / Co:MgAl2O4 is placed in a high temperature furnace and sintered at 1600°C for 10 days with a sintering pressure of 1MPa; the sintered composite laser crystal is annealed at 1200°C for 5 days to obtain a self-Q-switched composite laser element.

[0072] Example 5

[0073] This embodiment provides another self-Q-switched composite laser element, whose matrix is ​​Er:Gd3Ga5O12 Ceramic, the front end of the substrate is bonded with MgAl2O4 ceramic, and the rear end of the substrate is bonded with Co:MgAl2O4 ceramic.

[0074] The self-Q-switched composite laser element in this embodiment is prepared by the following method:

[0075] (1) Obtain bulk Er:Gd3Ga5O by high temperature sintering 12 , MgAl2O4 and Co:MgAl2O4 ceramic blanks.

[0076] (2)Place Er:Gd3Ga5O 12 The ceramic blank was cut into small pieces of 7mm×7mm×13mm, and the front and rear end faces of 7mm×7mm were polished to the following indicators: size 7mm×7mm×12mm, flatness ≥λ / 10@633nm, roughness Ra≥0.5nm, and optical defects were level 0; the polished front and rear faces were recorded as F1 and F2, respectively.

[0077] (3) MgAl2O4 and Co:MgAl2O4 ceramics were also cut into 7 mm × 7 mm × 3.5 mm squares. One 7 mm × 7 mm end face of the MgAl2O4 and Co:MgAl2O4 ceramics was polished, denoted as F1' and F2', respectively, until the conditions for photoresist were met, i.e., flatness ≥ λ / 10@633 nm, roughness Ra ≥ 0.5 nm, and optical defects were level 0.

[0078] (4)Place Er:Gd3Ga5O 12 , MgAl2O4 and Co:MgAl2O4 ceramics were placed in beakers filled with concentrated H3PO4, respectively, and then heated to 250°C in an oil bath. After maintaining a constant temperature of 250°C for 6 min, they were taken out, rinsed with distilled water and dried.

[0079] (5) Laser energy density of 3.60 J / cm 2 The 193nm excimer laser was irradiated on the F1 and F2 surfaces for 6min, and on the F1' and F2' surfaces for 5min, and then Er:Gd3Ga5O 12 The F1 and F2 surfaces of the ceramic are lightly bonded to the F1' surface of the MgAl2O4 ceramic and the F2' surface of the Co:MgAl2O4 ceramic respectively.

[0080] (6) The optically bonded component MgAl2O4 / Er:Gd3Ga5O 12 / Co:MgAl2O4 is placed in a high temperature furnace and sintered at 1500°C for 8 days with a sintering pressure of 0.8MPa; the sintered composite ceramic is annealed at 1200°C for 4 days to obtain a self-Q-switched composite laser element.

[0081] Example 6

[0082] This embodiment provides another self-Q-switched composite laser element, whose matrix is ​​Nd:Gd3Sc2Al3O 12 The ceramic has a MgAl2O4 crystal bonded to the front end of the substrate and a Co:MgAl2O4 crystal bonded to the rear end of the substrate.

[0083] The self-Q-switched composite laser element in this embodiment is prepared by the following method:

[0084] (1) High temperature sintering to obtain bulk Nd:Gd3Sc2Al3O 12 The ceramic blank is grown by the Czochralski method to obtain bulk MgAl2O4 and Co:MgAl2O4 crystal blanks.

[0085] (2) Combine Nd:Gd3Sc2Al3O 12 The ceramic blank was cut into small pieces of 5mm×5mm×9mm, and the front and rear end faces of 5mm×5mm were polished to the following indicators: size 5mm×5mm×8mm, flatness ≥λ / 10@633nm, roughness Ra≥0.5nm, and optical defects were level 0; the polished front and rear faces were recorded as F1 and F2, respectively.

[0086] (3) The MgAl2O4 and Co:MgAl2O4 crystals were also cut into 5 mm × 5 mm × 3 mm blocks. One 5 mm × 5 mm end face of the MgAl2O4 and Co:MgAl2O4 crystals was polished, denoted as F1' and F2', respectively, until the conditions for photoresist were met, i.e., flatness ≥ λ / 10@633 nm, roughness Ra ≥ 0.5 nm, and optical defects were level 0.

[0087] (4) Put Nd:Gd3Sc2Al3O 12 The ceramic was placed in a beaker filled with concentrated H2SO4, then heated to 220°C in an oil bath, kept constant at 220°C for 15 min, taken out, rinsed with distilled water and dried.

[0088] (5) Laser energy density of 3.40 J / cm 2 The 193nm excimer laser was irradiated on the F1 and F2 surfaces for 10min, and on the F1' and F2' surfaces for 10min, and then Nd:Gd3Sc2Al3O 12 The F1 and F2 surfaces of the ceramic are photobonded with the F1' surface of the MgAl2O4 crystal and the F2' surface of the Co:MgAl2O4 crystal respectively.

[0089] (6) The optically bonded component MgAl2O4 / Nd:Gd3Sc2Al3O12 / Co:MgAl2O4 is placed in a high temperature furnace and sintered at 1500°C for 7 days with a sintering pressure of 0.6MPa; the sintered composite element is annealed at 1200°C for 3 days to obtain a self-Q-switched composite laser element.

[0090] Example 7

[0091] After polishing the two-pass optical surfaces of the self-Q-switched composite laser element in Example 1-6, a self-Q-switched device is obtained.

[0092] In this embodiment, a self-Q-switched composite laser is provided, which is composed of a pump source, a collimating and focusing system, an input mirror, the self-Q-switched device obtained above, and an output mirror according to the direction of the optical path. Among them, the pump source adopts a domestic 976nm semiconductor laser, and the pump light passes through the optical fiber, the collimating and focusing system, and the total reflector, and then end-pumps the corresponding self-Q-switched device respectively. The laser resonant cavity can be a flat cavity or a flat concave cavity, and the cavity length is the length of the self-Q-switched device.

[0093] After testing and verification, efficient pulse laser output can be achieved, and the beam quality M 2 The factor is about 2.

[0094] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A self-Q-switched composite laser element, characterized in that: include: The matrix is ​​a doped garnet crystal and / or ceramic, and the composition of the garnet crystal and / or ceramic is A3B5O 12 , wherein A is any one or two of Y, Lu, Gd, and Sc, and B is any one or two of Al and Ga; and the doping elements are Yb and Er, or Er, or Nd; A first bonding body bonded to the front end of the substrate, wherein the first bonding body is a MgAl2O4 crystal and / or a ceramic; And a second bonding body bonded to the rear end of the substrate, wherein the second bonding body is Co:MgAl2O4 crystal and / or ceramic.

2. The self-Q-switched composite laser element according to claim 1, characterized in that: In the matrix, A is Y, or Lu, or Gd x Sc 1-x , or Y x Sc 1-x , or Lu x Sc 1-x ; B is Al, or Ga, or Al y Ga 1-y ; Where 0≤x, y≤1.

3. The self-Q-switched composite laser element according to claim 1, wherein: The self-Q-switched composite laser element is a regular quadrangular prism or a cylinder.

4. The self-Q-switched composite laser element according to claim 1, characterized in that: The dimensions of the bonding interfaces between the substrate, the first bonding body and the second bonding body are the same.

5. A method for preparing a self-Q-switched composite laser element according to any one of claims 1 to 4, characterized in that: The following steps are involved: preparing a substrate, a first bonding body and a second bonding body respectively; The first bonding body is bonded to the front end surface of the substrate, and the second bonding body is bonded to the rear end surface of the substrate to obtain the self-Q-switched composite laser element.

6. The preparation method according to claim 5, characterized in that: The substrate, the first bonding body and the second bonding body are crystals, and are grown by a Czochralski method; Alternatively, the substrate, the first bonding body and the second bonding body are ceramics and are made by a high-temperature sintering method.

7. The preparation method according to claim 5, characterized in that: The bonding adopts an optical adhesive bonding process, and the optical adhesive bonding process includes the following steps: Polishing the front end face and the rear end face of the substrate, and the bonding surfaces of the first bonding body and the second bonding body respectively to a photoresist-able condition; Cleaning the polished surface and irradiating the cleaned surface with ultraviolet light, and then photobonding the front end surface of the first bonding body and the rear end surface of the substrate, respectively; The composite component after photoresist bonding is subjected to high temperature sintering and annealing in sequence to obtain a self-Q-switched composite laser component; Preferably, the chemical reagent used for cleaning is H3PO4, H2SO4 or a combination of H2SO4 and H2O2; Preferably, the ultraviolet light irradiation uses a 193nm wavelength excimer laser with an energy density of 3 to 3.6 J / cm 2 , irradiation time is 5 to 15 minutes; Preferably, a pressure of 0.5 to 1 MPa may be applied during optical adhesive bonding; Preferably, the high temperature sintering temperature is 1400-1600°C, the sintering time is 7-10 days, and a pressure of 0.5-1 MPa is applied at the same time; Preferably, the annealing temperature is 1200° C. and the annealing time is not less than 3 days.

8. The preparation method according to claim 7, characterized in that: The photoresist conditions are that the surface flatness is ≥λ / 10@633nm, the roughness Ra is ≥0.5nm, and the optical defect is level 0.

9. A self-Q-switched device, characterized in that: The self-Q-switched composite laser element is formed by polishing the two light-passing end faces of the self-Q-switched composite laser element according to any one of claims 1 to 4, and then coating the polished two light-passing end faces with a dielectric film or not coating the two light-passing end faces.

10. A self-Q-switched laser, characterized in that: It comprises the self-Q-switched device as claimed in claim 9.

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