Laser gain device and preparation method thereof

Abstract

The present invention discloses a laser gain device and its preparation method. The device comprises, from bottom to top, a substrate, a bonding layer, a laser gain crystal, and a cladding. The bonding layer is formed by bonding a first bonding intercalation layer to a second bonding intercalation layer, the second bonding intercalation layer being located above the first bonding intercalation layer. The preparation method mainly involves heterogeneous bonding of the laser gain crystal to the substrate, etching the laser gain crystal, and preparing the cladding. The laser gain device of the present invention enables laser light to propagate within a micron-scale laser crystal waveguide. The higher optical density reduces the laser oscillation threshold and improves the slope efficiency of the laser output. Furthermore, the present invention has the advantages of small size, high stability, and ease of integration, providing a new possibility for integrated on-chip light sources.

Description

Technical Field

[0001] The present invention belongs to the field of laser technology, and in particular relates to a laser gain device and a preparation method thereof. Background Art

[0002] High-power all-solid-state lasers have important applications in industrial processing, national defense, scientific research, and other fields. With the development of these applications, high-power solid-state lasers are constantly moving towards higher power, higher efficiency, higher beam quality, smaller size, and more compact structure. The processing of laser gain devices is a key part of this process.

[0003] Currently, common gain structures include round rods, slabs, and sheets. Round rod laser crystals are the most mature and widely used solid-state laser structures. Their characteristic is that the gain medium is in the shape of a round rod. During operation, the oscillating / amplified laser travels along the axis of the medium. As the output power increases, the internal thermal effect of the solid laser gain medium seriously reduces the conversion efficiency and destroys the beam quality. To solve this problem, it is necessary to introduce heat dissipation modules such as water cooling, which makes the entire laser system more complicated. Chinese patent CN101242071 provides a sandwich structure gain medium slab and its preparation method. To facilitate optical processing, its thickness is on the order of millimeters. However, due to the limited thermal conductivity of the gain medium material, the output power of the slab laser using the slab structure gain medium of this structure is affected by the upper limit of the center temperature of the gain medium. When the pump is further increased, the output power will no longer increase.

[0004] Sheet laser crystals were first proposed by Adolf Giesen of the University of Stuttgart in Germany in the 1990s. The gain medium has a very thin thickness (typically 100-300 μm). The heat generated by sheet laser crystals is mainly conducted longitudinally to the cooling end face, which theoretically allows for stable operation with very high beam quality and a wide pump power range. However, they have strict polishing requirements, making it difficult to produce sheet lasers with good results. The aforementioned laser gain device structures transmit laser light over a large spatial range and have a relatively complex structure and large volume, becoming a bottleneck in laser development. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a laser gain device and a method for preparing the same, which enables laser light to propagate in a micron-scale laser crystal waveguide. The higher optical density reduces the threshold of laser oscillation and improves the slope efficiency of laser output. In addition, the device has the advantages of small size, high stability, and ease of integration, providing a new possibility for integrated on-chip light sources.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A laser gain device comprises, from bottom to top, a substrate, a bonding layer, a laser gain crystal and a cladding layer. The bonding layer is obtained by bonding a first bonding intercalation layer and a second bonding intercalation layer. The second bonding intercalation layer is located above the first bonding intercalation layer.

[0008] In the above solution, the substrate is a square made of semiconductor material with a side length of 3-5 inches and a thickness of 0.1mm-1mm.

[0009] In a further technical solution, the material of the substrate is one or more of silicon (Si), silicon carbide (SiC), silicon nitride (Si3N4), diamond, indium phosphide (InP), and gallium arsenide (GaAs).

[0010] In the above scheme, the material of the laser gain crystal includes one or more of yttrium aluminum garnet (YAG), yttrium vanadate (YVO4) crystal, gadolinium vanadate crystal (GdVO4), lutetium vanadate crystal (LuVO4), ruby ​​(Cr:Al2O3), emerald (Cr:BeAl2O4), and sapphire (Ti:Al2O3); the laser gain crystal contains doping elements, and the doping elements include one or more of Nd, Yb, Er, Tm, and Ho.

[0011] In the above solution, the materials of the first bonding intercalation layer and the second bonding intercalation layer include epoxy resin, dry film, bisbenzocyclobutene, polyimide, UV curing material, and Si, SiO2, Al2O3, Si3N4, and the thickness of the first bonding intercalation layer and the second bonding intercalation layer is 10μm-1mm.

[0012] In the above solution, the material of the cladding includes one or more of SiO2, Si3N4, and Si, and the cladding thickness is 10μm-10mm.

[0013] A method for preparing a laser gain device comprises the following steps:

[0014] Step 1: prepare the substrate and polish the laser gain crystal blank;

[0015] Step 2: depositing a first bonding intercalation layer on the surface of the substrate and depositing a second bonding intercalation layer on the polished surface of the laser gain crystal;

[0016] Step 3, bonding the first bonding intercalation layer and the second bonding intercalation layer;

[0017] Step 4: Graphically process the laser gain crystal;

[0018] Step five: depositing a cladding layer on the upper surface and side surfaces of the laser gain crystal.

[0019] In the above scheme, in step one, polishing is performed by mechanical polishing, chemical mechanical polishing or ion beam polishing, and the surface roughness after polishing is 0.01-5.00 nm; in step three, the bonding technology used includes adhesive bonding, anodic bonding, and plasma activated bonding.

[0020] In the above scheme, in step 2 and step 5, the deposition techniques used include chemical vapor deposition, atomic layer deposition, sputtering or electron beam evaporation.

[0021] In the above scheme, in step 4, the pattern transfer technology used in the patterning process includes photolithography, laser direct writing, nanoimprinting or screen printing; the material removal technology used includes wet etching or dry etching.

[0022] Through the above technical solution, the laser gain device and the preparation method thereof provided by the present invention have the following beneficial effects:

[0023] 1. In the present invention, the laser propagates in a micrometer-scale laser crystal waveguide. The higher light density reduces the threshold of laser oscillation and improves the slope efficiency of the laser output.

[0024] 2. The present invention has the advantages of small size, high stability, and easy integration, providing a new possibility for integrated on-chip light sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments or the prior art.

[0026] Figure 1 A schematic cross-sectional view of a laser gain device disclosed in an embodiment of the present invention;

[0027] Figure 2 This is a top view of the laser gain crystal disclosed in an embodiment of the present invention.

[0028] In the figure, 1, substrate; 2, first bonding intercalation layer; 3, second bonding intercalation layer; 4, laser gain crystal; 5, cladding layer. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] The present invention provides a laser gain device, such as Figure 1 and Figure 2 As shown, the specific embodiments of its structure and preparation method are as follows:

[0031] Example 1:

[0032] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0033] In this embodiment, the substrate 1 is made of SiC material with a thickness of 0.5 mm; the laser gain crystal 4 is made of Nd:YAG; it is polished mechanically; the surface roughness after polishing is 0.1 nm; the first bonding intercalation layer 2 is made of SiO2; it is prepared on the surface of the substrate 1 by chemical vapor deposition; the thickness is 0.2 mm; the second bonding intercalation layer 3 is made of SiO2; it is prepared on the surface of the laser gain crystal 4 by chemical vapor deposition; the thickness is 0.1 mm; the first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded by plasma activation; the pattern of the laser gain crystal 4 is transferred using photolithography technology; dry etching is used for material removal; the patterned laser gain crystal 4 has a thickness of 0.5 mm, a width of 0.5 mm, and a length of 100 mm; a cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4, and the cladding layer 5 is made of SiO2; it is prepared by electron beam evaporation and has a thickness of 1 mm.

[0034] Example 2:

[0035] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0036] In this embodiment, the substrate 1 is made of Si material and has a thickness of 1 mm; the laser gain crystal 4 is made of Er:YAG and is polished using an ion beam; the surface roughness after polishing is 0.05 nm; the first bonding intercalation layer 2 is made of Al2O3 and is prepared on the surface of the substrate 1 using atomic layer deposition; the thickness is 0.1 mm; the second bonding intercalation layer 3 is made of Al2O3 and is prepared on the surface of the laser gain crystal 4 using atomic layer deposition; the thickness is 0.1 mm; the first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded using plasma activation; the laser gain crystal 4 is patterned using laser direct writing technology; dry etching is used for material removal; the patterned laser gain crystal 4 has a thickness of 1 mm, a width of 1 mm, and a length of 1 m; a cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4, and the cladding layer 5 is made of SiO2 and is prepared using electron beam evaporation with a thickness of 10 mm.

[0037] Example 3:

[0038] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0039] In this embodiment, the substrate 1 is made of diamond material and has a thickness of 0.2 mm; the laser gain crystal 4 is made of TM:YVO4 and is polished using an ion beam; the surface roughness after polishing is 0.1 nm; the first bonding intercalation layer 2 is made of epoxy resin and is prepared on the surface of the substrate 1 using a chemical vapor deposition method; the thickness is 0.2 mm; the second bonding intercalation layer 3 is made of epoxy resin and is prepared on the surface of the laser gain crystal 3 using an atomic layer deposition method; the thickness is 0.2 mm; the first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded using an adhesive using a bonding technology; the laser gain crystal 4 is patterned using nanoimprint technology; wet etching is used for material removal; the patterned laser gain crystal 4 has a thickness of 0.3 mm, a width of 0.4 mm, and a length of 100 mm; a cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4, and the cladding layer 5 is made of Si3N4 and is prepared using a sputtering method; the thickness is 0.5 mm.

[0040] Example 4:

[0041] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0042] In this embodiment, the substrate 1 is made of Si3N4 material and has a thickness of 0.1 mm; the laser gain crystal 4 is made of Yb:GdO4 and is polished using an ion beam; the surface roughness after polishing is 0.5 nm; the first bonding intercalation layer 2 is made of Si and is prepared on the surface of the substrate 1 using electron beam evaporation; the thickness is 10 μm; the second bonding intercalation layer 3 is made of Si and is prepared on the surface of the laser gain crystal 3 using atomic layer deposition; the thickness is 10 μm; the first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded using plasma activation technology; the pattern of the laser gain crystal 4 is transferred using screen printing technology; dry etching is used to remove material; the patterned laser gain crystal 4 has a thickness of 0.1 mm, a width of 0.12 mm, and a length of 200 mm; a cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4, and the cladding layer 5 is made of SiO2 and is prepared using electron beam evaporation; the thickness is 0.2 mm.

[0043] Example 5:

[0044] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0045] In this embodiment, the substrate 1 is made of InP material and has a thickness of 0.5 mm; the laser gain crystal 4 is made of Tm:LuVO4; it is polished using an ion beam; the surface roughness after polishing is 0.1 nm; the first bonding intercalation layer 2 is made of bis-benzocyclobutene; it is prepared on the surface of the substrate 1 using chemical vapor deposition; the thickness is 20 μm; the second bonding intercalation layer 3 is made of bis-benzocyclobutene; it is prepared on the surface of the laser gain crystal 3 using chemical vapor deposition; the thickness is 20 μm; the first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded using adhesive bonding technology; the laser gain crystal 4 is patterned using screen printing technology; dry etching is used for material removal; the patterned laser gain crystal 4 has a thickness of 0.2 mm, a width of 0.24 mm, and a length of 500 mm; a cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4, and the cladding layer 5 is made of Si; it is prepared using electron beam evaporation and has a thickness of 0.5 mm.

[0046] Example 6:

[0047] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0048] In this embodiment, the substrate 1 is made of GaAs material and has a thickness of 0.2 mm. The first bonding intercalation layer 2 is made of UV curable material and is prepared on the surface of the substrate 1 by chemical vapor deposition and has a thickness of 50 μm. The second bonding intercalation layer 3 is made of UV curable material and is prepared on the surface of the laser gain crystal 3 by chemical vapor deposition and has a thickness of 50 μm. The first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded by adhesive technology. The laser gain crystal 4 is made of Ho:YAG and is polished by chemical mechanical method. The surface roughness after polishing is 0.05 nm. The pattern of the laser gain crystal 4 is transferred by screen printing technology. Dry etching is used for material removal. The patterned laser gain crystal 4 has a thickness of 0.5 mm, a width of 0.4 mm, and a length of 100 mm. A cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4. The cladding layer 5 is made of Si3N4 and is prepared by electron beam evaporation and has a thickness of 3 mm.

[0049] Example 7:

[0050] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0051] In this embodiment, the substrate 1 is made of Si material and has a thickness of 0.6 mm. The first bonding intercalation layer 2 is made of polyimide and is prepared on the surface of the substrate 1 using chemical vapor deposition and has a thickness of 10 μm. The second bonding intercalation layer 3 is made of polyimide and is prepared on the surface of the laser gain crystal 3 using chemical vapor deposition and has a thickness of 20 μm. The first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded using adhesive bonding technology. The laser gain crystal 4 is made of Ti:Al2O3 and is polished using chemical mechanical polishing. The surface roughness after polishing is 0.02 nm. The pattern of the laser gain crystal 4 is transferred using screen printing technology. Dry etching is used for material removal. The patterned laser gain crystal 4 has a thickness of 20 nm, a width of 30 nm, and a length of 10 μm. A cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4. The cladding layer 5 is made of Si3N4 and is prepared using electron beam evaporation and has a thickness of 20 μm.

[0052] Example 8:

[0053] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0054] In this embodiment, the substrate 1 is made of SiC material and has a thickness of 0.3 mm. The first bonding intercalation layer 2 is made of Si3N4 and is prepared on the surface of the substrate 1 by electron beam evaporation and has a thickness of 100 μm. The second bonding intercalation layer 3 is made of SiO2 and is prepared on the surface of the laser gain crystal 3 by sputtering and has a thickness of 200 μm. The first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded by anodic bonding technology. The laser gain crystal 4 is made of Cr:BeAl2O4 and is polished by ion beam and has a surface roughness of 0.1 nm after polishing. The pattern of the laser gain crystal 4 is transferred by screen printing technology. Dry etching is used for material removal. The patterned laser gain crystal 4 has a thickness of 200 nm, a width of 340 nm, and a length of 2 mm. A cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4. The cladding layer 5 is made of SiO2 and is prepared by electron beam evaporation and has a thickness of 0.5 mm.

[0055] Example 9:

[0056] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0057] In this embodiment, the substrate 1 is made of Si material and has a thickness of 0.6 mm. The first bonding intercalation layer 2 is made of dry film and is prepared on the surface of the substrate 1 using chemical vapor deposition and has a thickness of 0.5 mm. The second bonding intercalation layer 3 is made of epoxy resin and is prepared on the surface of the laser gain crystal 3 using chemical vapor deposition and has a thickness of 0.6 mm. The first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded using anodic bonding technology. The laser gain crystal 4 is made of Cr:Al2O3 and is polished using chemical mechanical polishing and has a surface roughness of 3 nm after polishing. The laser gain crystal 4 is patterned using laser direct writing technology and material is removed using wet etching. The patterned laser gain crystal 4 has a thickness of 0.6 mm, a width of 0.5 mm, and a length of 500 mm. A cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4. The cladding layer 5 is made of SiO2 and is prepared using chemical vapor deposition and has a thickness of 2 mm.

[0058] Example 10:

[0059] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0060] In this embodiment, the substrate 1 is made of SiC material; the thickness is 0.2 mm; the first bonding intercalation layer 2 is made of Si3N4; it is prepared on the surface of the substrate 1 using atomic layer deposition; the thickness is 20 μm; the second bonding intercalation layer 3 is made of SiO2; it is prepared on the surface of the laser gain crystal 3 using chemical vapor deposition; the thickness is 40 μm; the first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded using plasma activation technology; the laser gain crystal 4 is made of Yb:YAG; it is polished using chemical mechanical polishing; the surface roughness after polishing is 0.1 nm; the laser gain crystal 4 is patterned using laser direct writing technology; wet etching is used for material removal; the patterned laser gain crystal 4 has a thickness of 0.6 μm, a width of 0.5 μm, and a length of 200 mm; a cladding 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4, and the cladding 5 is made of Si3N4; it is prepared using chemical vapor deposition; the thickness is 1 mm.

[0061] Example 11:

[0062] A laser gain device comprises a substrate 1, a first bonding intercalation layer 2, a second bonding intercalation layer 3, a laser gain crystal 4, and a cladding layer 5 in sequence from bottom to top.

[0063] In this embodiment, the substrate 1 is made of SiC material and has a thickness of 0.4 mm. The first bonding intercalation layer 2 is made of Si3N4 and is prepared on the surface of the substrate 1 using atomic layer deposition and has a thickness of 0.2 mm. The second bonding intercalation layer 3 is made of Si3N4 and is prepared on the surface of the laser gain crystal 3 using chemical vapor deposition and has a thickness of 0.1 mm. The first bonding intercalation layer 2 and the second bonding intercalation layer 3 are bonded using plasma activation. The laser gain crystal 4 is made of Yb:YAG and is polished using chemical mechanical polishing and has a surface roughness of 0.05 nm after polishing. The laser gain crystal 4 is patterned using photolithography technology and material is removed using dry etching. The patterned laser gain crystal 4 has a thickness of 0.8 mm, a width of 0.6 mm, and a length of 500 mm. A cladding layer 5 is deposited on the upper surface and side surfaces of the laser gain crystal 4. The cladding layer 5 is made of SiO2 and is prepared using chemical vapor deposition and has a thickness of 2 mm.

[0064] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A laser gain device, characterized in that: From bottom to top, it includes a substrate, a bonding layer, a laser gain crystal and a cladding layer in sequence. The bonding layer is obtained by bonding a first bonding intercalation layer and a second bonding intercalation layer. The second bonding intercalation layer is located above the first bonding intercalation layer.

2. A laser gain device according to claim 1, characterized in that: The substrate is a square made of semiconductor material with a side length of 3-5 inches and a thickness of 0.1mm-1mm.

3. A laser gain device according to claim 2, characterized in that: The material of the substrate is one or more of silicon, silicon carbide, silicon nitride, diamond, indium phosphide, and gallium arsenide.

4. The laser gain device according to claim 1, wherein: The material of the laser gain crystal includes one or more of yttrium aluminum garnet, yttrium vanadate crystal, gadolinium vanadate crystal, lutetium vanadate crystal, ruby, emerald, and sapphire; the laser gain crystal contains doping elements, and the doping elements include one or more of Nd, Yb, Er, Tm, and Ho.

5. The laser gain device according to claim 1, wherein: The materials of the first bonding intercalation layer and the second bonding intercalation layer include epoxy resin, dry film, bisbenzocyclobutene, polyimide, UV curing material, and Si, SiO2, Al2O3, Si3N4. The thickness of the first bonding intercalation layer and the second bonding intercalation layer is 10μm-1mm.

6. The laser gain device according to claim 1, characterized in that: The material of the cladding layer includes one or more of SiO2, Si3N4, and Si, and the thickness of the cladding layer is 10 μm-10 mm.

7. A method for preparing a laser gain device, characterized in that: The steps include: Step 1: prepare the substrate and polish the laser gain crystal blank; Step 2: depositing a first bonding intercalation layer on the surface of the substrate and depositing a second bonding intercalation layer on the polished surface of the laser gain crystal; Step 3, bonding the first bonding intercalation layer and the second bonding intercalation layer; Step 4: Graphically process the laser gain crystal; Step five: depositing a cladding layer on the upper surface and side surfaces of the laser gain crystal.

8. The method for preparing a laser gain device according to claim 7, wherein: In step 1, polishing is performed by mechanical polishing, chemical mechanical polishing or ion beam polishing, and the surface roughness after polishing is 0.01-5.00 nm; in step 3, bonding is performed by adhesive bonding, anodic bonding, and plasma activated bonding.

9. The method for preparing a laser gain device according to claim 7, wherein: In step 2 and step 5, the deposition techniques used include chemical vapor deposition, atomic layer deposition, sputtering or electron beam evaporation.

10. The method for preparing a laser gain device according to claim 7, wherein: In step 4, the pattern transfer technology used in the patterning process includes photolithography, laser direct writing, nanoimprinting or screen printing; the material removal technology used includes wet etching or dry etching.

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