Vertical external cavity surface emitting laser and laser equipment

Abstract

The invention discloses a vertical external cavity surface emitting laser and laser equipment, and relates to the technical field of semiconductor light sources. The vertical external cavity surface emitting laser comprises a pump light source, a pump transparent reflecting layer and a first active layer which are arranged in a stacked mode, a first reflecting mirror is further arranged on the side, away from the pump transparent reflecting layer, of the first active layer, and a resonant cavity is formed by the first reflecting mirror and the pump transparent reflecting layer. A pumping light beam emitted by the pumping light source is projected to the first active layer through the pumping transparent reflecting layer to excite the first active layer to emit photons, and the photons are reflected back and forth in the resonant cavity and are subjected to stimulated radiation again in the back-and-forth reflection process to form a laser beam. According to the vertical external cavity surface emitting laser and the laser equipment, the volume of the vertical external cavity surface emitting laser can be reduced, and the coupling efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor light source technology, and more specifically, to a vertical external cavity surface-emitting laser and laser device. Background Technology

[0002] Vertical-External-Cavity Surface-Emitting Lasers (VECSELs), as hybrid laser devices combining the high gain characteristics of semiconductor lasers with the excellent beam quality of traditional solid-state lasers, have demonstrated significant advantages in high-power, high-beam-quality, and wavelength-tunable laser applications in recent years. A typical VECSEL structure usually includes a semiconductor gain active layer, a high-reflectivity distributed Bragg mirror, and a curved output coupling mirror located in the external cavity, collectively forming an optical resonator. To achieve population inversion, VECSELs require an external pump source to excite the active layer.

[0003] In existing technologies, VECSELs commonly use edge-emitting lasers as pump sources. Although edge-emitting lasers have high output power and a mature commercial foundation, their separate packaging from the VECSEL results in a large overall system size and complex assembly, which is not conducive to miniaturization and integration. Summary of the Invention

[0004] The purpose of this application is to provide a vertical external cavity surface-emitting laser and laser device that can reduce the size of the vertical external cavity surface-emitting laser and improve the coupling efficiency.

[0005] The embodiments of this application are implemented as follows: A first aspect of this application provides a vertical external cavity surface-emitting laser, including a pump light source, a pump transparent reflective layer, and a first active layer stacked together. A first reflector is also disposed on the side of the first active layer away from the pump transparent reflective layer. The first reflector and the pump transparent reflective layer form a resonant cavity. The pump beam emitted from the pump light source is projected onto the first active layer through the pump transparent reflective layer, exciting the first active layer to emit photons. The photons are reflected back and forth in the resonant cavity and are stimulated to radiate again during the back and forth reflection process to form a laser beam.

[0006] As one possible implementation, a superlens is disposed between the pump light source and the pump transparent reflective layer. The superlens is used to focus the pump beam emitted from the pump light source and project it onto the first active layer.

[0007] As one possible implementation, the pump light source is a vertically excited light source, comprising a first reflective layer, a second active layer, and a second reflective layer stacked sequentially.

[0008] As one possible implementation, the line connecting the center of the first reflector and the center of the first active layer has a preset angle with the light-emitting surface of the first active layer, and also includes a first coupling reflector symmetrically arranged with the first reflector. The first coupling reflector, the first reflector, and the pump transparent reflector layer are used to reflect the laser beam respectively.

[0009] As one possible implementation, the line connecting the center of the first reflector and the center of the first active layer has a preset angle with the light-emitting surface of the first active layer, and also includes a semiconductor saturable absorber mirror symmetrically arranged with the first reflector. The semiconductor saturable absorber mirror, the first reflector, and the pump transparent reflective layer are used to reflect the laser beam respectively, and the semiconductor saturable absorber mirror is used to lock the mode of the laser beam.

[0010] As one possible implementation, the line connecting the center line of the first reflector and the center line of the first active layer is perpendicular to the light-emitting surface of the first active layer, and the reflecting surface of the first reflector has a preset angle with the light-emitting surface. A second coupling reflector is also provided on one side of the first reflector, and the laser beam is reflected sequentially along the direction of the first reflector, the second coupling reflector, the first reflector, and the pump transparent reflector layer.

[0011] As one possible implementation, a birefringent filter is disposed between the first active layer and the first reflector, and a frequency doubling crystal is disposed between the second coupling reflector and the first reflector.

[0012] As one possible implementation, a heat dissipation substrate is provided on the side of the pump light source away from the pump transparent reflective layer.

[0013] As one possible implementation, a heat dissipation crystal is also provided between the superlens and the pump transparent reflective layer.

[0014] A second aspect of this application provides a laser device including the aforementioned vertical external cavity surface-emitting laser.

[0015] The beneficial effects of the embodiments of this application include: The vertical external cavity surface-emitting laser (VECS) provided in this application includes a pump source, a pump transparent reflective layer, and a first active layer stacked together. A first reflector is also disposed on the side of the first active layer away from the pump transparent reflective layer. The first reflector and the pump transparent reflective layer form a resonant cavity. The pump beam emitted from the pump source is projected onto the first active layer through the pump transparent reflective layer, exciting photons emitted from the first active layer. The photons undergo round-trip reflection within the resonant cavity and are stimulated to emit laser beams again during the round-trip reflection process. This application embodiment stacks the pump source and the first active region, integrating them into a single structure, eliminating the need for external pump modules, collimating lenses, and mounting brackets. The overall thickness can be controlled at the millimeter level, significantly reducing the laser's volume and improving integration. Furthermore, when the pump source is integrated inside the laser, the pump beam propagates within the laser, eliminating air interface reflection losses and achieving a coupling efficiency close to 100%, thus improving coupling efficiency. Therefore, the laser of this application embodiment can reduce the volume of a VECS and improve coupling efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is one of the structural schematic diagrams of a vertical external cavity surface-emitting laser provided in the embodiments of this application; Figure 2 This is the second schematic diagram of the structure of a vertical external cavity surface-emitting laser provided in the embodiments of this application; Figure 3 This is the third schematic diagram of the structure of a vertical external cavity surface-emitting laser provided in the embodiments of this application; Figure 4 Fourth schematic diagram of the structure of the vertical external cavity surface-emitting laser provided in the embodiments of this application; Figure 5 The fifth schematic diagram of the structure of the vertical external cavity surface-emitting laser provided in the embodiments of this application.

[0018] Icons: 100 - Vertical external cavity surface-emitting laser; 110 - Pump source; 120 - Pump transparent reflective layer; 130 - First active layer; 140 - First reflector; 150 - Superlens; 161 - First coupling mirror; 162 - Semiconductor saturable absorber mirror; 163 - Second coupling mirror; 164 - Frequency doubling crystal; 165 - Birefringent filter; 166 - Frequency doubling mirror; 171 - Heat dissipation substrate; 172 - Heat dissipation crystal. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of this application, not all embodiments. Similar reference numerals and letters in the following drawings indicate similar items. Once an item is defined in one drawing, it does not need to be further defined in other drawings.

[0020] The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and should not be construed as limiting this application. The terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0021] Unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to connections within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0022] Please refer to the reference. Figures 1 to 5 This application provides a vertical external cavity surface-emitting laser 100, including a pump light source 110, a pump transparent reflective layer 120 and a first active layer 130 stacked together. A first reflector 140 is also disposed on the side of the first active layer 130 away from the pump transparent reflective layer 120. The first reflector 140 and the pump transparent reflective layer form a resonant cavity. The pump beam emitted from the pump light source 110 is projected onto the first active layer 130 through the pump transparent reflective layer 120, exciting the first active layer 130 to emit photons. The photons are reflected back and forth in the resonant cavity and are stimulated to radiate again during the back and forth reflection process to form a laser beam.

[0023] Specifically, in this embodiment, the pump light source 110 is used to provide excitation energy, and the first active layer 130 is used to generate stimulated emission under the excitation of the pump beam. It can be understood that the first active layer 130 is disposed on the pump transparent reflective layer 120, and the first reflector 140 is disposed on the other side of the first active layer 130 away from the pump transparent reflective layer 120. The first reflector 140 and the pump transparent reflective layer form a resonant cavity.

[0024] When the laser is operating, the pump beam emitted by the pump source 110 is projected onto the first active region. After absorbing high-energy photons, the semiconductor material in the first active region is excited to the conduction band, forming electron-hole pairs. These pairs then recombine radiatively back to the valence band and emit photons, generating initial photons. These photons undergo multiple round-trip reflections within the resonant cavity. Each time they pass through the first active region, they are continuously amplified through stimulated emission, forming coherent laser light, which is then emitted as laser light after certain conditions are met.

[0025] In this embodiment, the pump light source 110 and the first active region are stacked and bonded together, integrating them into a single structure. This eliminates the need for external pump modules, collimating lenses, and mounting brackets, allowing the overall thickness to be controlled within millimeters, thus significantly reducing the laser's size and improving integration. Furthermore, when the pump light source 110 is integrated inside the laser, the pump beam propagates within the laser, eliminating air interface reflection losses and achieving a coupling efficiency close to 100%, thereby improving coupling efficiency. Therefore, the laser of this embodiment can reduce the size of the vertical external cavity surface-emitting laser 100 and improve coupling efficiency.

[0026] Specifically, in practical applications, when the pump light source 110 includes a first reflective layer, a second active layer, and a second reflective layer stacked sequentially, a pump transparent reflective layer 120 can be disposed on the upper surface of the second reflective layer, and then the first active layer 130 can be disposed on the pump transparent reflective layer 120. During laser fabrication, the pump light source 110 can be formed by sequentially laying out the layers, and then the pump transparent reflective layer 120 and the first active layer 130 can be deposited on the pump light source 110.

[0027] The pump transparent reflective layer 120 is a wavelength selective optical thin film that is highly transparent to the pump beam but highly reflective to the laser beam. Specifically, the pump beam and the laser beam have different wavelengths. For example, if the wavelength of the pump beam is 808 nm, the transmittance of the pump transparent reflective layer 120 to the pump beam is greater than 95%. If the wavelength of the laser beam is 1064 nm, the reflectance of the pump transparent reflective layer 120 to the pump beam is greater than 99%. Specifically, the pump transparent reflective layer 120 can be a dielectric film DBR or a semiconductor DBR, and its design center wavelength is located in the laser band, not the pump band.

[0028] Optional, such as Figures 1 to 5 As shown, a superlens 150 is disposed between the pump light source 110 and the pump transparent reflective layer 120. The superlens 150 is used to focus the pump beam emitted from the pump light source 110 and project it onto the first active layer 130.

[0029] The superlens 150 is a two-dimensional planar optical element composed of a subwavelength-scale nanoantenna array, typically with a thickness on the order of hundreds of nanometers to a few micrometers. The superlens 150 is positioned between the pump source 110 and the pump transparent reflective layer 120 to focus the diverging beam emitted by the pump source 110, precisely converging it into the upper first active layer 130. When the laser is operating, the pump beam first passes through the superlens 150 located directly above it. The superlens 150, through its nanostructural units, focuses the pump beam into a spot with a diameter of tens to hundreds of micrometers, projecting it onto the first active layer 130 and exciting it.

[0030] Specifically, the superlens 150 can be directly fabricated on the upper surface of the pump source 110 to achieve on-chip optical control. In the stacking direction, the thickness of the superlens 150 is small, thereby significantly reducing the stacking height of the laser in the vertical direction.

[0031] The superlens 150 can be customized with a phase distribution to suit the divergence characteristics of the pump light source 110, achieving diffraction-limited focusing with a focusing efficiency of over 85%. It avoids energy loss caused by spherical aberration and astigmatism in traditional microlenses, allowing more pump beams to be effectively absorbed and improving light-to-light conversion efficiency.

[0032] As an feasible approach, such as Figures 1 to 5 As shown, the pump light source 110 is a vertical excitation light source, including a first reflective layer, a second active layer and a second reflective layer stacked in sequence.

[0033] The emitted beam of a side-emitting laser exhibits a highly asymmetrical elliptical distribution and a large divergence angle, resulting in low pump light coupling efficiency and requiring a complex collimation and shaping optical system. Furthermore, the one-dimensional linear array structure of the side-emitting laser makes it difficult to achieve uniform surface pumping, easily leading to hot spots on the gain chip, limiting output power and affecting beam quality. In this embodiment, the pump source 110 is configured as a vertical excitation source. The vertical cavity structure naturally supports a circular symmetrical beam, with a divergence angle as low as 6.6° in its orthogonal direction and an M² factor close to 1.1–1.5, approaching the diffraction limit. In other words, the pump source 110 possesses advantages such as vertical surface emission, a circular beam, and a low divergence angle.

[0034] The vertical excitation source provides a high-quality pump beam to the first active region, thereby improving the quality of the laser beam. In addition, the surface pumping method of the vertical excitation source ensures that the pump light energy is evenly distributed on the surface of the gain chip, avoiding local overheating and achieving efficient and uniform pumping and thermal management of the second active region, thereby further improving the quality of the laser beam.

[0035] Specifically, the first and second reflective layers can be Bragg reflectors composed of multiple pairs of alternating high / low refractive index materials, such as alternating AlGaAs / GaAs or AlGaN / GaN layers, with a reflectivity >99.9%. In practical applications, the first reflective layer serves as the bottom reflective layer and is typically N-type doped; the second reflective layer serves as the top reflective layer and is typically P-type doped, with an internal projection structure, such as an oxide confinement hole, serving as the output coupling structure to ensure the pump beam exits vertically upwards.

[0036] The first active layer 130 adopts a multi-quantum-well structure, such as 3–5 In0.2Ga0.8As / GaAs quantum wells, each with a thickness of about 7–10 nm, sandwiched between barrier layers, which has advantages such as high gain coefficient, narrow gain spectrum and low threshold current.

[0037] Optional, such as Figure 2 As shown, the line connecting the center of the first reflector 140 and the center of the first active layer 130 has a preset angle with the light-emitting surface of the first active layer 130. It also includes a first coupling reflector 161 symmetrically arranged with the first reflector 140. The first coupling reflector 161, the first reflector 140 and the pump transparent reflector layer 120 are used to reflect the laser beam respectively.

[0038] Specifically, the first reflecting mirror 140 and the first coupling reflecting mirror 161 are symmetrically arranged on both sides of the perpendicular bisector of the first active layer 130, forming a V-shaped reflection pair to ensure precise overlap of the laser beam during its round trip and maintain resonance conditions. The laser beam forms a triangular structure between the pump transparent reflecting layer 120, the first reflecting mirror 140, and the first coupling reflecting mirror 161, creating a closed V-shaped round trip path. The laser beam gains stimulated emission each time it passes through the first active layer 130. Specifically, when the single-pass gain exceeds the loss within the resonant cavity, stable oscillation is established, and the beam is emitted.

[0039] As can be seen from the above optical path description, the V-shaped round-trip path allows the laser to have a longer optical path. Furthermore, in a single round trip, the laser traverses the first active layer 130 twice, effectively doubling the gain length and improving gain efficiency. Additionally, the V-shaped optical path exhibits significant diffraction losses at its edges, making it difficult to maintain oscillations in higher-order modes, thus giving the laser stronger mode selectivity.

[0040] Specifically, the value of the preset included angle is not limited in this application embodiment. For example, it can be 30°, 45°, 60°, or other angle values.

[0041] As an feasible approach, such as Figure 3As shown, the line connecting the center of the first reflector 140 and the center of the first active layer 130 has a preset angle with the light-emitting surface of the first active layer 130. It also includes a semiconductor saturable absorber 162 symmetrically arranged with the first reflector 140. The semiconductor saturable absorber 162, the first reflector 140 and the pump transparent reflective layer 120 are used to reflect the laser beam respectively. The semiconductor saturable absorber 162 is used to lock the mode of the laser beam.

[0042] Specifically, the first reflector 140 and the semiconductor saturable absorber 162 are symmetrically arranged on both sides of the vertical line of the first active layer 130, forming a triangular structure with the pump transparent reflector 120 below the first active layer 130. The laser beam forms a V-shaped folding back-and-forth path between the three, and experiences intensity selective loss each time it passes through the semiconductor saturable absorber 162, thus achieving self-starting passive mode-locking.

[0043] The laser beam exits from the active layer and splits into two beams: one beam is directed towards the first reflecting mirror 140, and after being reflected by the first reflecting mirror 140, it obliquely passes through the first active layer 130; the other beam is directed towards the semiconductor saturable absorber mirror 162, and is reflected by its surface. Initially, the reflection is weak because it is not saturated. The two beams cross and reciprocate within the cavity, forming a closed V-shaped optical path. Intensity fluctuations exist within the resonant cavity; strong light spikes saturate the absorption layer of the semiconductor saturable absorber mirror 162, causing a sharp increase in reflectivity (e.g., from 70% to 95%), and reducing losses; weak light is strongly absorbed by the semiconductor saturable absorber mirror 162, resulting in high losses; after multiple round trips, the strong light spikes are selectively amplified, and the weak light is suppressed; at the same time, the gain spectral width of the first active layer 130 supports multi-longitudinal-mode oscillations, and the semiconductor saturable absorber mirror 162 causes each longitudinal mode to be phase-locked, forming periodic ultrashort pulses. The pulse circulates within the V-shaped cavity, gaining gain each time it passes through the first active layer 130, and is shaped by the semiconductor saturable absorber mirror 162. The pulse width is determined by the gain bandwidth, the recovery time of the semiconductor saturable absorber mirror 162, and the dispersion. The repetition frequency is determined by the effective cavity length. The laser outputs picosecond-level, GHz-level repetition rate pulse trains from a portion of the transmission region of the semiconductor saturable absorber mirror 162 or the first reflector mirror 140, thereby achieving ultrafast pulse output.

[0044] Among them, the semiconductor saturable absorber mirror 162 is a nonlinear optical element that has high absorption under low light intensity and saturates absorption under high light intensity, thus exhibiting high reflectivity.

[0045] Optional, such as Figure 4As shown, the line connecting the center line of the first reflector 140 and the center line of the first active layer 130 is perpendicular to the light-emitting surface of the first active layer 130, and the reflecting surface of the first reflector 140 has a preset angle with the light-emitting surface. A second coupling reflector 163 is also provided on one side of the first reflector 140. The laser beam is reflected sequentially along the direction of the first reflector 140, the second coupling reflector 163, the first reflector 140, and the pump transparent reflective layer 120.

[0046] The line connecting the centerline of the first reflector 140 and the centerline of the first active layer 130 is perpendicular to the light-emitting surface, meaning the first reflector 140 is directly opposite the center of the active layer in the horizontal direction, and the reflective surface and the light-emitting surface have a preset angle, causing the reflective surface to be tilted. The second coupling reflector 163 is disposed on one side of the first reflector 140, forming a double-mirror folding unit with the first reflector 140. After the laser beam is emitted from the first active layer 130, it cycles along the following path: the first reflector 140 emitted from the first active layer 130 is reflected by the first reflector 140 to the second coupling reflector 163, then reflected by the second coupling reflector 163 to the first reflector 140, and then reflected by the first reflector 140 to the pump transparent reflective layer 120. This path forms a type 7 folded optical path. The laser beam passes through the first active layer 130 multiple times in a single round trip. The pump transparent reflective layer 120 acts as a bottom high-reflection mirror, completing the resonant closed loop.

[0047] As can be seen from the above optical path, the Type 7 round trip path gives the laser a longer optical path, and in a single round trip, the laser beam crosses the first active layer 130 twice, doubling the equivalent gain length and improving the gain efficiency.

[0048] As an feasible approach, such as Figure 5 As shown, a birefringent filter 165 is disposed between the first active layer 130 and the first reflector 140, and a frequency doubling crystal 164 is disposed between the second coupling reflector 163 and the first reflector 140.

[0049] The birefringent filter 165 is disposed between the first active layer 130 and the first reflector 140, utilizing the polarization interference effect of the birefringent crystal to achieve narrowband wavelength selection. Specifically, the birefringent crystal produces different phase delays for different wavelength beams, and in conjunction with the intracavity polarization state, only specific wavelengths satisfy the resonance condition, while others are suppressed. The frequency doubling crystal 164 is disposed between the second coupling reflector 163 and the first reflector 140, used to convert the nonlinear frequency of infrared fundamental frequency light into visible light. That is, it is used to convert infrared fundamental frequency light with a wavelength of 1064nm into green light with a wavelength of 532nm. The frequency doubling crystal 164 can be a barium β-borate crystal because barium β-borate crystals have a large nonlinear coefficient, a high damage threshold, and a wide phase matching angle, making them suitable for high-power frequency doubling. Specifically, type I or type II phase matching can be achieved by precisely controlling the crystal cutting angle.

[0050] When the laser is working, the pump source 110 emits a pump beam, which penetrates perpendicularly through the pump transparent reflective layer 120 and is projected onto the first active layer 130. The first active layer 130 undergoes stimulated emission, generating infrared fundamental frequency laser photons. The fundamental frequency light exits from the active layer and enters the birefringent filter 165. The birefringent filter 165 only allows narrow-band wavelengths (such as 1064.0 ± 0.2 nm) to pass through efficiently, while other wavelengths are suppressed due to destructive interference, outputting single-mode or narrow-linewidth fundamental frequency light, thus improving the subsequent frequency doubling efficiency. The frequency-selected fundamental frequency light is reflected by the first reflector 140 and enters the transverse optical path; it reaches the frequency doubling crystal 164, where a second harmonic is generated under a strong light field, converting the 1064 nm infrared fundamental frequency light into 532 nm green light. The frequency doubling process requires phase matching conditions, which are achieved by the birefringent characteristics of the BBO (Birefringent-Bearing Optimizer).

[0051] In this structure, the second coupling mirror 163 no longer serves as the coupling output, therefore it needs to be designed to have the highest reflectivity for the fundamental frequency light to achieve the maximum intracavity optical power. The first mirror 140 requires a special coating design to achieve high reflection of the fundamental frequency light and high transmission of the second harmonic. The unconverted fundamental frequency light is reflected by the second coupling mirror 163, returns to the first mirror 140, and is then reflected back to the first active layer 130 by the first mirror 140; finally, the 532nm green light directly passes through the first mirror 140 to reach the frequency doubling mirror 166 located on the side of the first mirror 140 away from the second coupling mirror 163, such as... Figure 5 As shown, this enables the output of the visible light band, that is, the second harmonic is formed between the second coupling mirror and the frequency doubling mirror 166 to form a resonant cavity.

[0052] It should be noted that the embodiments in this application use 1064nm infrared light and 532nm visible light as examples for illustration. Those skilled in the art can select the wavelength range according to the actual situation.

[0053] Optional, such as Figures 1 to 5 As shown, a heat dissipation substrate 171 is provided on the side of the pump light source 110 away from the pump transparent reflective layer 120.

[0054] The heat dissipation substrate 171 serves to conduct heat and also provides mechanical support for the overall laser. Specifically, the heat dissipation substrate 171 is directly attached or bonded to the substrate of the pump light source 110 or the back side of the first reflective layer (bottom reflective layer), forming an efficient heat conduction path. The material of the heat dissipation substrate 171 can be aluminum.

[0055] As an feasible approach, such as Figures 1 to 5 As shown, a heat dissipation crystal 172 is also disposed between the superlens 150 and the pump transparent reflective layer 120.

[0056] The heat dissipation crystal 172 serves two purposes: firstly, it efficiently dissipates the waste heat generated by the first active layer 130; secondly, it provides a flat and stable substrate for the material layers disposed thereon. The waste heat is conducted downwards from the first active layer 130, through the pump transparent reflective layer 120, and reaches the heat dissipation crystal 172. Due to its high thermal conductivity, the heat is rapidly diffused laterally and conducted downwards; finally, it is dissipated into the environment through the pump light source 110 heat dissipation substrate 171.

[0057] Understandably, the heat dissipation crystal 172 must not obstruct the normal propagation of the pump beam; therefore, the material of the heat dissipation crystal 172 needs to have high transmittance to the pump beam. For example, the heat dissipation crystal 172 can be made of sapphire crystal. Sapphire has a thermal conductivity 5–10 times that of conventional GaAs DBR, significantly reducing thermal resistance, preventing laser failure due to excessive temperature, and improving the reliability and lifespan of the laser.

[0058] This application also provides a laser device including the aforementioned vertical external cavity surface-emitting laser 100. The laser device has the same structure and beneficial effects as the vertical external cavity surface-emitting laser 100. Since the structure and beneficial effects of the vertical external cavity surface-emitting laser 100 have been described in detail in the foregoing embodiments, they will not be repeated here.

[0059] The above description is merely an optional embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0060] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

Claims

1. A vertical-external-cavity surface-emitting laser, characterized by, The vertical external cavity surface emitting laser comprises a pump light source, a pump transparent reflection layer and a first active layer which are stacked in sequence, and a first mirror is arranged on a side of the first active layer away from the pump transparent reflection layer, the first mirror and the pump transparent reflection layer form a resonant cavity, a pump light beam emitted by the pump light source is projected to the first active layer through the pump transparent reflection layer, and the first active layer emits photons, the photons are reflected in the resonant cavity and are excited again to form a laser beam during the reflection.

2. The VECSEL according to claim 1, characterized in that An ultralens is arranged between the pump light source and the pump transparent reflection layer, and the ultralens is used for focusing and projecting the pump light beam emitted by the pump light source to the first active layer.

3. The VECSEL according to claim 1, characterized in that The pump light source is a vertical excitation light source, and comprises a first reflection layer, a second active layer and a second reflection layer which are stacked in sequence.

4. The VECSEL of claim 1, wherein, The first mirror and the center line of the first active layer are connected with the light emitting surface of the first active layer at a preset angle, and a first coupling mirror is arranged symmetrically with the first mirror, and the first coupling mirror, the first mirror and the pump transparent reflection layer are used for reflecting the laser beam respectively.

5. The VECSEL of claim 1, wherein, The first mirror and the center line of the first active layer are connected with the light emitting surface of the first active layer at a preset angle, and a first coupling mirror is arranged symmetrically with the first mirror, and the first coupling mirror, the first mirror and the pump transparent reflection layer are used for reflecting the laser beam respectively, and the semiconductor saturable absorber mirror is used for locking the mode of the laser beam.

6. The VECSEL according to claim 5, characterized in that The first mirror and the center line of the first active layer are connected with the light emitting surface of the first active layer at a preset angle, and a first coupling mirror is arranged symmetrically with the first mirror, and the first coupling mirror, the first mirror and the pump transparent reflection layer are used for reflecting the laser beam respectively, and the semiconductor saturable absorber mirror is used for locking the mode of the laser beam.

7. The VECSEL according to claim 6, characterized in that The first mirror and the center line of the first active layer are connected with the light emitting surface of the first active layer at a preset angle, and a first coupling mirror is arranged symmetrically with the first mirror, and the first coupling mirror, the first mirror and the pump transparent reflection layer are used for reflecting the laser beam respectively, and the semiconductor saturable absorber mirror is used for locking the mode of the laser beam.

8. The VECSEL of claim 1, wherein, The first mirror and the center line of the first active layer are connected with the light emitting surface of the first active layer at a preset angle, and a first coupling mirror is arranged symmetrically with the first mirror, and the first coupling mirror, the first mirror and the pump transparent reflection layer are used for reflecting the laser beam respectively, and the semiconductor saturable absorber mirror is used for locking the mode of the laser beam.

9. The VECSEL of claim 2, wherein, The first mirror and the center line of the first active layer are connected with the light emitting surface of the first active layer at a preset angle, and a first coupling mirror is arranged symmetrically with the first mirror, and the first coupling mirror, the first mirror and the pump transparent reflection layer are used for reflecting the laser beam respectively, and the semiconductor saturable absorber mirror is used for locking the mode of the laser beam.

10. A laser apparatus, characterized by comprising: The first mirror and the center line of the first active layer are connected with the light emitting surface of the first active layer at a preset angle, and a first coupling mirror is arranged symmetrically with the first mirror, and the first coupling mirror, the first mirror and the pump transparent reflection layer are used for reflecting the laser beam respectively, and the semiconductor saturable absorber mirror is used for locking the mode of the laser beam. The first mirror and the center line of the first active layer are connected with the light emitting surface of the first active layer at a preset angle, and a first coupling mirror is arranged symmetrically with the first mirror, and the first coupling mirror, the first mirror and the pump transparent reflection layer are used for reflecting the laser beam respectively, and the semiconductor saturable absorber mirror is used for locking the mode of the laser beam. The vertical external cavity surface emitting laser comprises the vertical external cavity surface emitting laser according to any one of claims 1-9.

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