High-stability laser output system

Abstract

The invention relates to a high-stability laser output system, which comprises a pumping source, a coupling assembly, a laser medium crystal and a resonant cavity, and is characterized in that the pumping source provides pumping light, the pumping light passes through the coupling assembly and then enters a non-central position of the laser medium crystal, and laser energy is provided to excite electrons in the laser medium crystal to jump to a high energy level; under the action of a pumping source, electrons in the laser medium crystal are transited to a high energy level to form population inversion, the laser medium crystal is arranged on a rotating shaft of a rotating motor, the motor drives the laser medium crystal to rotate continuously, and the drop point of pumping light on the crystal is changed continuously. Each point of the laser medium crystal obtains sufficient cooling time, so that each part of the crystal is uniformly heated, the problem that the crystal is damaged due to local overheating caused by long-time fixed-point irradiation is effectively avoided, the thermal stress of the crystal is reduced, the overall temperature of the crystal is reduced, and the stability and reliability of a laser output system are remarkably improved; the resonant cavity is used for providing optical feedback, so that laser beams are reflected and enhanced in the cavity for multiple times, and the output intensity of laser is improved.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular to a high-stability laser output system. Background Art

[0002] In the internal structure of a solid-state laser, when the pump light is irradiated to the laser medium crystal, the photons interact with the electrons in the crystal, exciting the electrons to jump from a low energy level to a high energy level. This process is accompanied by the absorption and conversion of energy. Part of the energy will be converted into thermal energy, leading to the generation of heat in the crystal. If the solid-state laser runs continuously for a long time without an effective heat dissipation mechanism, the continuous accumulation of heat will dramatically increase the temperature of the crystal.

[0003] The increase in crystal temperature will bring a series of negative effects: Increased thermal stress: Uneven heating of the crystal can lead to internal thermal stresses, which can cause micro-deformations or cracks in the crystal structure, thus affecting its optical properties.

[0004] Degradation of optical performance: As the temperature increases, the optical parameters of the crystal, such as the refractive index and absorption coefficient, will change, which may lead to a decrease in the quality of the laser beam, such as an increase in the beam divergence angle and a shift in the laser wavelength.

[0005] Thermal lens effect: The temperature gradient inside the crystal will cause a change in the refractive index, similar to the effect of a lens, which may cause the laser beam to focus or diverge inside the crystal, affecting the stability and directionality of the laser beam.

[0006] Crystal damage: Long-term high-temperature operation will accelerate the aging process of the crystal, which may cause changes in the chemical or physical properties of the crystal material, or even cause structural damage such as melting, evaporation or phase change, thus seriously shortening the service life of the crystal.

[0007] In order to avoid these problems, solid-state lasers usually use complex heat dissipation systems, such as heat sinks, cooling fans, coolant circulation, etc., to ensure that the laser medium crystal can maintain a low temperature during operation. In addition, by optimizing the incident angle and distribution of the pump light, and using materials with high thermal conductivity and specially designed heat dissipation structures, heat accumulation can be further reduced and the thermal management efficiency of the laser can be improved.

[0008] In summary, solid-state lasers must effectively solve the problem of heat accumulation during operation to prevent crystal overheating and structural damage, thereby ensuring long-term stable operation of the laser and laser output quality. Summary of the invention

[0009] Based on this, in order to solve the above problems, the present invention provides a high-stability laser output system, which greatly improves the stability and reliability of the laser output system.

[0010] To achieve the above-mentioned purpose, the present invention provides a high-stability laser output system, comprising a pump source, a coupling component, a laser medium crystal and a resonant cavity, wherein the pump source provides pump light and is incident on a non-central position of the laser medium crystal after passing through the coupling component, so as to provide laser energy to excite electrons in the laser medium crystal to transition to a high energy level; under the action of the pump source, the electrons in the laser medium crystal transition to a high energy level, forming a population inversion; the laser medium crystal is arranged on a rotating shaft of a rotating motor, and the motor drives the laser medium crystal to rotate continuously; during the operation of the laser output system, the landing point of the pump light on the crystal changes continuously, and a heat sink is attached to the laser medium crystal; the resonant cavity is used to provide optical feedback, so that the laser beam is reflected and enhanced multiple times in the cavity, thereby improving the output intensity of the laser.

[0011] In one specific embodiment, the incident position of the pump light deviates from the center of the laser medium crystal by 1-2 mm.

[0012] In one specific embodiment, the rotary motor is a stepper motor or a servo motor.

[0013] In one specific embodiment, the coupling component is a microlens arranged in a two-dimensional array, and each microlens is connected to a micro-electromechanical system.

[0014] In one specific embodiment, a control system is also included, in which a plurality of temperature sensors and stress sensors are evenly distributed on the surface of the laser medium crystal, which monitor the temperature value and stress value of the laser medium crystal under the action of pump light in real time and transmit the temperature value and stress value to the control system.

[0015] In one specific embodiment, the control system controls the micro-electromechanical system to adjust the position, angle or intensity of the pump light of a single micro-lens according to the received temperature value and stress value.

[0016] In one of the specific embodiments, the resonant cavity includes a semiconductor saturable absorption mirror for modulating the light pulse in the laser cavity to output ultrashort pulse laser.

[0017] In one of the specific embodiments, a beam collector is provided at at least one of the output end of the coupling component, the output end of the laser medium crystal, and the output end of the resonant cavity.

[0018] In one of the specific embodiments, the beam collector includes a beam inlet and a beam collecting tube obliquely arranged in the beam collecting area, and a circulating cooling liquid path or a circulating cooling gas path is arranged around the beam collecting tube.

[0019] In one specific embodiment, the circulating cooling liquid circuit or the circulating cooling gas circuit includes a cooling liquid or cooling gas inlet and at least two interconnected cooling pipes running through the X-axis direction of the beam collecting tube, at least two cooling pipes running through the Y-axis direction of the beam collecting tube, and at least two cooling pipes running through the Z-axis direction of the beam collecting tube, as well as a cooling liquid or cooling gas outlet, and the cooling pipes in the X-axis direction, the Y-axis direction, and the Z-axis direction are interconnected.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a high-stability laser output system, in which the landing point of the pump light on the laser medium crystal is constantly changing, ensuring that each point of the laser medium crystal obtains sufficient cooling time, so that each part of the crystal is heated evenly, effectively avoiding the problem of local overheating and damage to the crystal due to long-term fixed-point irradiation, reducing the thermal stress of the crystal, and lowering the overall temperature of the crystal, thereby significantly improving the stability and reliability of the laser output system. The heat sink with high thermal conductivity is closely attached to the laser medium crystal, effectively and quickly dissipating the heat generated by the crystal, lowering the overall temperature of the crystal, further improving the stability of the system and the laser output quality, not only improving the thermal management efficiency of the system, but also helping to extend the service life of the entire laser output system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the overall structure of a high-stability laser output system of the present invention.

[0022] Figure 2 The figure is a schematic diagram of the trajectory of the pump light landing on the crystal of a high-stability laser output system of the present invention.

[0023] Figure 3 The figure is a schematic diagram of the position of a beam collector in a high-stability laser output system of the present invention.

[0024] Figure 4 The figure is a schematic cross-sectional structure diagram of a beam collector of a high-stability laser output system of the present invention.

[0025] Figure 5 The figure is a schematic diagram of the three-dimensional structure of a beam collector of a high-stability laser output system of the present invention. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0028] like Figure 1 As shown, this embodiment provides a high-stability laser output system, including a pump source 10, a coupling component 20, a laser medium crystal 30 and a resonant cavity 40 connected by an optical path. The pump source 10 is a high-power semiconductor pump source. The pump light emitted by the pump source 10 can be effectively absorbed by the laser medium crystal 30. The wavelength of the pump light is 808nm or 980nm. The pump source 10 provides pump light and after passing through the coupling component 20, it is incident on a non-central position of the laser medium crystal 30 at a specific angle, so as to provide laser energy to excite the laser medium crystal 30. The electrons in the laser medium crystal 30 transition to a high energy level. Under the action of the pump source 10, the electrons in the laser medium crystal 30 transition to a high energy level, forming a population inversion. The laser medium crystal 30 is a Nd:YAG crystal, which is arranged on the rotating shaft of the rotating motor 50. The rotating motor 50 is a stepping motor or a servo motor. The stepping motor has precise stepping control capability, and the step angle is between 0.36° and 1.8°. During the operation of the laser output system, the rotation angle of the laser medium crystal 30 can be precisely controlled, thereby ensuring uniform heating of the crystal at different positions. The servo motor has the characteristics of fast response speed and high control accuracy. Its speed control accuracy is ±0.01%. It can quickly adjust the speed according to the real-time temperature and stress of the crystal to ensure the stable operation of the crystal. The electronic speed of the motor is 100-1000 rpm. The laser medium crystal 30 is driven to rotate by the motor 50. During the operation of the laser output system, the landing point of the pump light on the laser medium crystal 30 is constantly changing, which can make the laser medium crystal 30 more evenly heated and reduce the performance degradation caused by local overheating. Figure 2As shown, the trajectory of the landing point of the pump light on the laser medium crystal 30 is circular or elliptical. A heat sink 60 is attached to the laser medium crystal 30. The heat sink 60 is made of a material with a high thermal conductivity, which can be copper or aluminum, and can quickly dissipate the heat generated by the crystal to provide a guarantee for the generation of lasers; the resonant cavity 40 is 10-50cm long and is used to provide optical feedback, so that the laser beam is reflected and enhanced multiple times in the cavity, and the light beam is reflected and limited by the reflectors at both ends, so that the laser beam is reflected multiple times in the resonant cavity, and the light of a specific frequency and direction can form a stable oscillation in the cavity, thereby improving the output intensity of the laser. The resonant cavity 40 includes a semiconductor saturable absorber mirror (SESAM) (not shown in the figure), which is used to modulate the light pulse in the laser cavity, and realize the mode selection and compression of the light pulse through the absorption and release characteristics of light, thereby outputting ultrashort pulse lasers. The embodiment provides a high-stability laser output system, in which the landing point of the pump light on the laser medium crystal is constantly changed, ensuring that each point of the laser medium crystal has sufficient cooling time, so that each part of the crystal is heated evenly, effectively avoiding the problem of local overheating and damage to the crystal due to long-term fixed-point irradiation, reducing the thermal stress of the crystal, and lowering the overall temperature of the crystal, thereby significantly improving the stability and reliability of the laser output system. The heat sink with high thermal conductivity is closely attached to the laser medium crystal, effectively dissipating the heat generated by the crystal quickly, reducing the overall temperature of the crystal, further improving the stability of the system and the quality of laser output, not only improving the thermal management efficiency of the system, but also helping to extend the service life of the entire laser output system.

[0029] In one specific embodiment, the position where the pump light is incident deviates from the center of the laser medium crystal 30 by 1-2 mm. For example, the position where the pump light is incident deviates from the center of the laser medium crystal 30 by about 1.5 mm. This can ensure that the pump light can effectively stimulate electron transitions while avoiding problems such as crystal damage caused by excessive concentration of energy at the center.

[0030] In one specific embodiment, the coupling component 20 is a microlens arranged in a two-dimensional array. Exemplarily, the microlens is arranged in an array of 5x5-100x100. The size of the microlens is extremely small, and the diameter of each microlens is about 10-50um, which is conducive to the fine control of the light beam. Each microlens is connected to a microelectromechanical system (MEMS). The MEMS system can accurately control the position and angle of the microlens, and its control accuracy can reach sub-micron level, wherein the position control accuracy can reach 0.1um, and the angle control accuracy can reach 0.01°. Through the control of the microlens by MEMS, the microlens converges and shapes the divergent light beam emitted by the pump source 10, thereby improving the coupling efficiency of the pump light and the laser medium crystal 30.

[0031] like Figure 1As shown, in one of the specific embodiments, a control system 70 is also included. A plurality of temperature sensors and stress sensors are evenly distributed on the surface of the laser medium crystal 30. The temperature value and stress value of the laser medium crystal 30 under the action of the pump light are monitored in real time and transmitted to the control system 70. The control system 70 controls the micro-electromechanical system to adjust the position, angle or intensity of the pump light of a single micro-lens according to the received temperature value and stress value. When the temperature sensor detects that the crystal temperature is too high, the control system 70 adjusts the angle of the micro-lens through the micro-electromechanical system to make the pump light more evenly distributed on the crystal surface and reduce the local temperature; or reduce the intensity of the pump light to reduce the heat generation of the crystal. When the stress sensor detects that the stress inside the crystal is too large, the control system can adjust the position of the micro-lens, optimize the incident direction of the pump light, alleviate the stress concentration phenomenon inside the crystal, and improve the life of the crystal.

[0032] like Figure 3-Figure 5 As shown, in one specific embodiment, a beam collector 80 is provided at at least one position among the output end of the coupling component 20, the output end of the laser medium crystal 30, and the output end of the resonant cavity 40. The beam collector 80 is used to collect the laser beams that are not effectively utilized at the output end of the coupling component 20, the output end of the laser medium crystal 30, and the output end of the resonant cavity 40 to prevent them from causing damage to the surrounding environment. For example, in industrial processing scenarios, due to the high laser energy, if the unused laser beams are directly irradiated onto surrounding objects, it may cause a fire or damage the equipment, and therefore needs to be collected and processed by the beam collector 80.

[0033] In one specific embodiment, the beam collector 80 includes a beam inlet 801 and a beam collecting tube 802 three-dimensionally inclined in the beam collecting area, and a circulating cooling pipeline 803 is arranged around the beam collecting tube 802. The circulating cooling pipeline is a circulating cooling liquid circuit or a circulating cooling gas circuit. The inclination angle of the beam collecting tube 802 is 30°-60°. Preferably, the inclination angle of the beam collecting tube 802 is 45°. The unused laser beam is absorbed in the beam collecting tube 802 to prevent damage to the laser components or the surrounding environment.

[0034] In one specific embodiment, the circulating cooling liquid circuit or circulating cooling gas circuit includes a cooling liquid or cooling gas inlet 8031 ​​and at least two interconnected cooling pipes running through the beam collecting tube 802 in the X-axis direction, at least two cooling pipes running through the beam collecting tube 802 in the Y-axis direction, and at least two cooling pipes running through the beam collecting tube 802 in the Z-axis direction, as well as a cooling liquid or cooling gas outlet 8032. The cooling pipes in the X-axis direction, the Y-axis direction, and the Z-axis direction are interconnected. A high-stability laser output system provided in this embodiment forms a three-dimensional cooling network around the beam collector 80, so that the beam collecting tube 802 can be evenly cooled in three-dimensional directions. After the cooling liquid or cooling gas enters the circulating cooling pipeline from the inlet, it flows through the three-dimensional cooling network and is discharged from the outlet, taking away the heat of the beam collector during operation, so that the overall laser output system maintains a suitable and stable operating temperature, thereby improving the stability and reliability of the laser output system.

[0035] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0036] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A high-stability laser output system, characterized in that: Including pump source, coupling components, laser medium crystal and resonant cavity, The pump source provides pump light and is incident on a non-central position of the laser medium crystal after passing through a coupling component, so as to provide laser energy to excite electrons in the laser medium crystal to transition to a high energy level; Under the action of the pump source, the electrons in the laser medium crystal transition to a high energy level, forming a population inversion. The laser medium crystal is arranged on the rotating shaft of a rotating motor, and the motor drives the laser medium crystal to rotate continuously. During the operation of the laser output system, the landing point of the pump light on the crystal changes continuously. A heat sink is attached to the laser medium crystal. The resonant cavity is used to provide optical feedback, so that the laser beam is reflected multiple times in the cavity and enhanced, thereby improving the output intensity of the laser.

2. A high-stability laser output system according to claim 1, characterized in that: The incident position of the pump light deviates from the center of the laser medium crystal by 1-2 mm.

3. A high-stability laser output system according to claim 1, characterized in that: The rotating motor is a stepping motor or a servo motor.

4. The high-stability laser output system according to claim 1, characterized in that: The coupling component is a microlens arranged in a two-dimensional array, and each microlens is connected to a micro-electromechanical system.

5. A high-stability laser output system according to claim 4, characterized in that: It also includes a control system. A plurality of temperature sensors and stress sensors are evenly distributed on the surface of the laser medium crystal, which monitor the temperature and stress values ​​of the laser medium crystal under the action of pump light in real time and transmit the temperature and stress values ​​to the control system.

6. A high-stability laser output system according to claim 5, characterized in that: The control system controls the micro-electromechanical system to adjust the position, angle or intensity of the pump light of a single micro-lens according to the received temperature value and stress value.

7. The high-stability laser output system according to claim 1, characterized in that: The resonant cavity includes a semiconductor saturable absorption mirror, which is used to modulate the light pulse in the laser cavity and output ultrashort pulse laser.

8. The high-stability laser output system according to claim 1, characterized in that: A beam collector is arranged at at least one position among the output end of the coupling component, the output end of the laser medium crystal, and the output end of the resonant cavity.

9. A high-stability laser output system according to claim 8, characterized in that: The beam collector comprises a beam inlet and a beam collecting tube obliquely arranged in the beam collecting area, and a circulating cooling liquid path or a circulating cooling gas path is arranged around the beam collecting tube.

10. A high-stability laser output system according to claim 9, characterized in that: The circulating cooling liquid circuit or the circulating cooling gas circuit includes a cooling liquid or cooling gas inlet and at least two interconnected cooling pipes running through the X-axis direction of the beam collecting tube, at least two cooling pipes running through the Y-axis direction of the beam collecting tube, and at least two cooling pipes running through the Z-axis direction of the beam collecting tube, as well as a cooling liquid or cooling gas outlet. The cooling pipes in the X-axis direction, the Y-axis direction and the Z-axis direction are interconnected.

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