Multi-channel bbo crystal temperature control furnace integrated with angle-temperature-stress tuning

Abstract

The application provides a multi-channel BBO crystal temperature control furnace integrated with angle-temperature-stress tuning, comprising a heat preservation shell, a bottom adapter plate, a copper temperature guide plate, a BBO crystal, a crystal mounting seat, a crystal pressing block, an indium sheet, a center positioning circular plate, a center positioning circular plate pressing block, a center positioning circular plate mounting seat, a thermoelectric refrigerator, a platinum resistance temperature sensor, a TEC heat sink, a linear module and a vacuum stepping motor, and can realize high-precision temperature control, angle tuning and stress tuning of the multi-channel BBO crystal. Through the integrated design of multiple components, the technical problems of the prior art, such as the inability to simultaneously control the temperature of multiple BBO crystals with high precision, the insufficient mechanical angle tuning precision, the low switching efficiency and the inaccurate stress control, are solved, and the application has the advantages of compact structure, convenient adjustment and adaptation to a vacuum environment, and is suitable for scenes such as laser frequency conversion and nonlinear optical experiments, realizes wide-band phase matching tuning, and improves the stability and precision of photon output.

Description

Technical Field

[0001] This invention relates to the field of nonlinear optical crystal temperature control technology and phase matching tuning, and particularly to a multi-channel BBO crystal temperature control furnace with integrated angle-temperature-stress tuning. Background Technology

[0002] BBO crystals, as high-performance nonlinear optical crystals, possess advantages such as wide transmission band, large nonlinear optical coefficient, high damage threshold, and good optical homogeneity, and are widely used in laser frequency conversion, laser pulse compression, and nonlinear optical imaging. In practical applications, the optical properties of BBO crystals are extremely sensitive to temperature, stress state, and pump light incident angle. Precise control of these parameters is key to achieving efficient phase-matching tuning and improving photon output quality.

[0003] Currently, existing BBO crystal temperature control devices and tuning technologies have several shortcomings: First, most adopt a single-channel design, which cannot achieve high-precision temperature control of multiple BBO crystals simultaneously. When wide-band phase-matching tuning is required, crystals must be manually replaced, which is cumbersome, inefficient, and prone to crystal damage or positioning deviation during replacement. Second, temperature control accuracy is insufficient. Existing devices mostly use a single temperature control element, resulting in uneven heat conduction, large temperature control errors, and difficulty in meeting the requirements of high-precision experiments. Furthermore, the heat preservation effect is poor, and heat dissipation is rapid, increasing energy consumption for temperature control. Third, angle tuning and stress tuning are independent of each other, resulting in low adjustment accuracy. Angle tuning is mostly done manually, leading to large positioning errors. Stress adjustment can easily cause uneven stress on the crystal, resulting in stress concentration, damaging the crystal, or affecting optical performance. Fourth, the structural design of existing devices is unreasonable and cannot be adapted to vacuum environments, limiting their application in high-vacuum nonlinear optical experiments. Fifth, the coordination of various components is poor. The adjustment of temperature, angle, and stress interferes with each other, making it difficult to achieve coordinated tuning, affecting phase matching effect and photon output stability.

[0004] In view of the shortcomings of the existing technology, there is an urgent need for a BBO crystal temperature control furnace design that can achieve multi-channel coordination, high-precision temperature control, angle-stress coordinated tuning, and has a compact structure that is adaptable to the vacuum environment, so as to solve the technical problems existing in the current technology and promote the technological progress in the field of nonlinear optics. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-channel BBO crystal temperature control furnace with integrated angle-temperature-stress tuning. This is a BBO crystal temperature control furnace with multi-phase matching method collaboration and high-precision temperature control, which solves the problems of multiple crystals not being able to be simultaneously controlled with high precision, insufficient mechanical angle tuning accuracy, and inability to switch quickly. In addition, the BBO crystal temperature control furnace can be used in a vacuum environment.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An integrated angle-temperature-stress tuned multi-channel BBO crystal temperature control furnace includes an insulating shell, a bottom adapter plate, a copper temperature conducting plate, a BBO crystal, a crystal mounting base, a crystal pressing block, an indium sheet, a torque adjusting screw, a center positioning circular plate, a center positioning circular plate pressing block, a center positioning circular plate mounting base, a thermoelectric cooler (TEC), a platinum resistance temperature sensor, a TEC heat sink, a linear module, and a vacuum stepper motor.

[0008] The thermal insulation shell has openings at both ends, and the opening positions correspond to the BBO crystal mounting positions. The laser enters from one small hole and exits from the other small hole. The thermal insulation shell is fixed to the bottom adapter plate by screws.

[0009] The BBO crystal is mounted on a crystal mounting base, which is mounted on a copper heat-conducting plate. The crystal pressure block is pressed and fixed to the BBO crystal by a torque adjusting screw. The torque adjusting screw is used to fix the BBO crystal and also to adjust the mechanical stress on the BBO crystal. The crystal pressure block has a threaded hole, and the installation screw allows for micro-angle adjustment of a single BBO crystal.

[0010] The central positioning circular plate is mounted on the central positioning circular plate mounting base, which is mounted on the bottom adapter plate and fixed by the central positioning circular plate pressure block. It is used for center alignment of the laser and the BBO crystal, and the small hole it opens also functions as an aperture.

[0011] The copper thermal conductive plate is attached to the bottom end of the TEC, and a small hole is provided in the middle to install a platinum resistance temperature sensor. Thermal grease is applied to the contact surfaces of the TEC, the copper thermal conductive plate, and the TEC heat sink. The TEC is attached and fixed to the TEC heat sink.

[0012] The linear module is connected to a vacuum stepper motor. The bottom adapter plate, the copper heat-conducting plate, the heat-insulating shell, and the central positioning circular plate mounting base are all installed on the linear module to realize the switching of multiple BBO crystals.

[0013] Beneficial effects:

[0014] 1. This invention provides a multi-channel BBO crystal temperature control furnace design with integrated angle-temperature-stress tuning. This device integrates multi-channel design with angle, temperature, and stress coordinated tuning functions, enabling simultaneous high-precision temperature control of multiple BBO crystals. Through the coordinated action of a vacuum stepper motor and a linear module, it achieves smooth and rapid switching of multiple crystals with high switching efficiency and high positioning accuracy. It solves the problems of cumbersome switching and large positioning deviation in existing single-channel designs, and can meet the requirements of wide-band phase matching tuning.

[0015] 2. This invention adopts a bidirectional temperature-controlled TEC series design, combined with an oxygen-free copper heat-conducting plate (thickness 3-6mm), an aluminum alloy heat sink (heat dissipation fin thickness 1-4mm, spacing 1-2mm), and a platinum resistance temperature sensor. The temperature control range is 10℃ to 100℃, with high temperature control accuracy (≤±0.01℃) and uniform heat conduction. The surface temperature uniformity of the BBO crystal is ≤±0.2℃. At the same time, the heat insulation shell is made of polytetrafluoroethylene material (thickness 2-5mm) and covered with an aluminum foil reflective layer, which has a good heat insulation effect, reduces heat loss, and lowers temperature control energy consumption. The temperature feedback from the platinum resistance temperature sensor further improves the temperature control accuracy, solving the defects of insufficient temperature control accuracy and poor heat insulation effect of existing devices.

[0016] 3. This invention achieves angle-stress coordinated tuning. Through the engagement of the bottom circular hole and the U-shaped grooves at both ends of the crystal mounting base, precise angle adjustment of the BBO crystal from 0-10° is achieved, resulting in high adjustment accuracy and good stability. The adjustment is achieved by adjusting the screw torque of the crystal clamping block (adjustment range 0-0.2). This technology enables precise stress adjustment of the BBO crystal. Combined with the buffering effect of the indium sheet (0.1-0.2mm thick), it avoids stress concentration damage to the crystal and improves thermal conductivity. This solves the problems of independent angle and stress tuning, low precision, and easy crystal damage in the existing technology.

[0017] 4. The present invention has a compact structure and reasonable design, with good synergy among its components. The adjustment of temperature, angle, and stress does not interfere with each other, enabling coordinated tuning, improving phase matching effect and photon output stability. The central positioning circular plate has both positioning and aperture functions, filtering stray light and further improving photon output quality. The overall device is adaptable to vacuum environments, broadening its application range, and can be used in various scenarios such as laser frequency conversion, nonlinear optical imaging, and high-vacuum nonlinear optical experiments.

[0018] 5. The present invention is easy to install and debug. All components are fixed with screws, which makes it easy to disassemble, maintain and replace. The selected materials have good high temperature resistance, corrosion resistance and thermal conductivity. The device has a long service life and high operational stability, which can meet the needs of long-term high-precision experiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the device structure of the present invention;

[0020] Figure 2 This is a flowchart of the angle-temperature-stress tuning process of the present invention. Detailed Implementation

[0021] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0022] This invention provides a multi-channel BBO crystal temperature control furnace with integrated angle-temperature-stress tuning. Through multi-component integrated design, the device achieves coordinated tuning of temperature, angle, and stress, solving the problems of multiple crystals not being able to be controlled at the same time, cumbersome switching, and insufficient tuning accuracy in the prior art. It also has a compact structure, is suitable for vacuum environments, and can be widely used in laser frequency conversion, nonlinear optical experiments, and other scenarios.

[0023] Figure 1 This is a schematic diagram of the device structure of the present invention. (See attached diagram.) Figure 1 As shown, the temperature-controlled furnace includes: an insulation shell 1, a bottom adapter plate 2, a copper temperature-conducting plate 3, a BBO crystal 4, a crystal mounting base 5, a crystal pressing block 6, an indium sheet 7, a torque adjusting screw 9, a center positioning circular plate 10, a center positioning circular plate pressing block, a center positioning circular plate mounting base, a thermoelectric cooler (TEC) 11, a platinum resistance temperature sensor 8, a TEC heat sink 12, a linear module 13, and a vacuum stepper motor 14.

[0024] The heat insulation shell 1 has holes at both ends, and the positions of the holes correspond to the installation positions of the BBO crystal 4. The laser enters from one small hole and exits from the other small hole. The heat insulation shell 1 is fixed to the bottom adapter plate 2 by screws.

[0025] In this embodiment, the BBO crystal 4 is mounted on the crystal mounting base 5. In one embodiment, the crystal mounting base 5 is L-shaped, and the BBO crystal 4 is mounted on two sides of the L-shaped crystal mounting base 5. The crystal mounting base 5 is mounted on the copper heat-conducting plate 3. The crystal clamping block 6 is pressed and fixed to the BBO crystal 4 by a torque adjusting screw 9. The torque adjusting screw 9 is used both to fix the BBO crystal 4 and to adjust the mechanical stress on the BBO crystal 4; that is, changing the torque of the torque adjusting screw 9 adjusts the mechanical stress on the BBO crystal 4. The crystal clamping block 6 has threaded holes, allowing for micro-angle adjustment of a single BBO crystal 4 after the screw is installed, thereby changing the incident angle of the pump light. In one embodiment, the crystal clamping block 6 can also be L-shaped and contact the other two sides of the BBO crystal 4. The BBO crystal 4 is a cube, with two sides being the light-incoming and light-outcoming surfaces, which do not contact the crystal clamping block 6 or the crystal mounting base 5. Two of the remaining four sides can be selected to contact the crystal mounting base 5, and the remaining two sides contact the crystal clamping block 6. An indium sheet 7 is attached to the contact surface between the BBO crystal 4 and the crystal pressing block 6. The indium sheet 7 is used to avoid the crystal pressing block causing large stress concentration in the BBO crystal 4, and at the same time improves the thermal conductivity and temperature uniformity between the crystal and the crystal pressing block 6.

[0026] The center positioning circular plate 10 is mounted on the center positioning circular plate mounting base, which is mounted on the bottom adapter plate 2. The center positioning circular plate 10 is fixed by the center positioning circular plate pressure block and is used for center alignment of the laser and the BBO crystal 4. After alignment, the pump light can be incident on the center of the crystal according to the distance between each crystal. The small hole opened in the center positioning circular plate 10 also serves as an aperture.

[0027] The bottom of the copper thermal conductive plate 3 is attached to the TEC 11, and a small hole is provided in the middle to install the platinum resistance temperature sensor 8. Temperature feedback is achieved through the platinum resistance temperature sensor 8. Together with the TEC 11, the BBO crystal 4 can achieve high-precision temperature control. Thermal grease is applied to the contact surfaces of the TEC 11, the copper thermal conductive plate 3, and the TEC heat sink 12. The TEC 11 and the TEC heat sink 12 are attached and fixed.

[0028] The linear module 13 is connected to the vacuum stepper motor 14. The bottom adapter plate 2 and all components above it, including the crystal mounting base 5, the copper heat-conducting plate 3, and the heat-insulating shell 1, are installed on the linear module 13 to realize the switching of multiple BBO crystals 4, thereby realizing the collaborative work of multiple crystals to achieve the purpose of wide band.

[0029] The following is for reference. Figure 2 The assembly process of the temperature-controlled furnace of the present invention will be described in conjunction with specific implementation methods:

[0030] Step (1): Place the BBO crystal 4 on the crystal mounting base 5. The crystal mounting base 5 is made of copper and is fixed on the copper thermal conductive plate 3. The bottom of the crystal mounting base 5 has a round hole, which, together with the U-shaped grooves at both ends, enables the rotation adjustment of the BBO crystal 4, thereby adjusting the incident angle of the pump photon. Adjustment method: The round hole at the bottom of the crystal mounting base 5 is matched with the boss on the copper thermal conductive plate 3. Using the boss as the pivot, the rotation adjustment of the BBO crystal 4 can be achieved. In addition, after the crystal mounting base 5 is rotated, the installation position of the fastening screw that mounts the crystal mounting base 5 to the copper thermal conductive plate 3 changes accordingly. The fastening screw is connected to the threaded hole on the copper thermal conductive plate through the U-shaped groove. The design of the U-shaped groove enables the fastening screw to remain reliably fixed after the position changes. The copper material has excellent thermal conductivity, which can quickly transfer the heat of the BBO crystal 4 to the copper temperature-conducting plate 3, ensuring the temperature control response speed; the combination design of the bottom round hole and the U-shaped grooves at both ends can realize the rotation adjustment of the BBO crystal 4 from 0-10°, with high adjustment precision, which can accurately match the requirements of different pump light incident angles.

[0031] In one embodiment, before placing the BBO crystal 4 on the crystal mounting base 5, the mating surface of the crystal mounting base 5 can be surface treated to ensure that the surface roughness is ≤0.8μm, so as to avoid uneven force on the BBO crystal 4 due to unevenness of the mating surface; the mating surface of the BBO crystal 4 is cleaned to remove surface dust, oil and impurities, so as to prevent impurities from affecting the thermal conductivity and crystal fixation stability.

[0032] In another embodiment, before placing the BBO crystal 4 on the crystal mounting base 5, the mating surfaces of the BBO crystal 4 and the crystal mounting base 5 are surface-treated to ensure that the surface roughness is ≤1.6μm. Before mating, a thin layer of thermally conductive grease is applied to the mating surfaces, and the thermal conductivity of the grease is ≥5. This enhances the thermal conductivity of the bonding surface, ensuring that the temperature of the BBO crystal 4 can be quickly and evenly transferred to the copper temperature-conducting plate 3, facilitating accurate temperature data acquisition by the platinum resistance temperature sensor 8, improving temperature control uniformity and response speed; the width of the U-shaped grooves at both ends of the crystal mounting base 5 matches the diameter of the fastening screws, and anti-slip washers are set between the fastening screws and the U-shaped grooves to prevent loosening after adjustment, ensuring the stability of the angle adjustment, with a rotation adjustment angle range of 0-10°.

[0033] Step (2): The BBO crystal 4 is fixed by a crystal clamping block 6 made of an L-shaped copper plate. Small holes are opened on the upper end and side end face of the crystal clamping block 6. The crystal clamping block 6 is installed on the crystal mounting base 5 by two torque adjusting screws 9 opposite to the L-shape of the crystal mounting base 5, so as to fix the BBO crystal 4 in the U-shaped structure formed by the two L-shapes. The torque of the screws is adjusted to adjust the force on the BBO crystal 4. An indium sheet 7 is placed on the contact surface between the crystal clamping block 6 and the BBO crystal 4 to avoid hard contact and improve the uniformity of heat conduction. The L-shaped crystal clamping block 6 can fix the BBO crystal 4 from two directions to ensure the stability of the fixation, while avoiding stress concentration caused by fixation in one direction. The indium sheet 7 has good ductility and thermal conductivity, which can effectively buffer the pressure of the crystal clamping block on the BBO crystal, avoid stress concentration damage to the crystal, and improve the uniformity of heat conduction.

[0034] The thickness of the indium sheet 7 can be flexibly selected according to the size of the BBO crystal 4 and the stress requirements. In one embodiment, it is 0.1-0.2mm. Before bonding, a thin layer of thermally conductive silicone grease is applied to the contact surface between the indium sheet 7 and the crystal pressing block 6 to further improve the uniformity of heat conduction and enhance the tightness of the bonding between the indium sheet 7 and the crystal pressing block 6, so as to avoid gaps that would lead to a decrease in thermal conductivity. The L-shaped structure of the crystal pressing block 6 matches the size of the BBO crystal 4 to ensure that it can be tightly bonded to the upper and right end faces of the BBO crystal 4, so as to avoid loosening after fixing.

[0035] In step (2), the screw is made of stainless steel, which has good corrosion resistance and mechanical strength. An elastic washer is placed between the screw and the threaded hole of the crystal pressure block 6 to prevent stripping of the screw during tightening and to buffer the pressure of the screw on the crystal pressure block 6, preventing deformation of the crystal pressure block 6 and uneven stress on the BBO crystal 4. The torque adjustment range of the screw is 0-0.2. Based on the size and stress tolerance of the BBO crystal 4, the torque is precisely adjusted to achieve the required stress tuning effect, avoiding damage to the crystal due to excessive torque or instability due to insufficient torque.

[0036] Step (3): Two TEC 11 units connected in series are attached to the bottom of the copper thermal conductive plate 3. Thermal grease is applied to the contact surfaces of the TEC 11 units with the copper thermal conductive plate 3 and the TEC heat sink 12. The two TEC 11 units connected in series achieve temperature control of the BBO crystal 4. The other end of the TEC 11 unit is attached and fixed to the TEC heat sink 12. Thermal grease can be applied before attaching it to the heat sink 12 of the TEC 11 unit. A platinum resistance temperature sensor 8 is installed in the small hole in the middle of the copper thermal conductive plate 3 for temperature feedback. The whole system achieves high-precision temperature control of the BBO crystal 4. The design of two TEC 11 units connected in series can improve the temperature control power and temperature control accuracy. The temperature control range can reach 10℃ to 100℃, and the temperature control accuracy is ≤±0.01℃, which meets the requirements of high-precision experiments. The application of thermal grease can enhance the temperature control of the TEC 11 units. The tight fit between 11 and the copper thermal conductive plate 3 and the TEC heat sink 12 improves thermal conductivity and prevents heat buildup that could damage the TEC. The TEC heat sink 12 is made of aluminum alloy and has heat dissipation fins with a thickness of 1-4mm and a spacing of 1-2mm between adjacent fins. This allows for rapid dissipation of the heat generated by the TEC 11, ensuring stable temperature control.

[0037] Among them, TEC 11 uses a bidirectional temperature-controlled thermoelectric cooler, which can realize bidirectional regulation of heating and cooling. It can accurately control the working temperature of BBO crystal 4 based on the temperature data fed back by platinum resistance temperature sensor 8. The temperature control range is 10℃ to 100℃, and the temperature control accuracy is ≤±0.01℃, meeting the requirements of different phase matching conditions. Two TEC 11s are connected in series to ensure that their working states are consistent, improve temperature control stability, and avoid temperature deviation. The contact surfaces of TEC 11 with copper thermal conductive plate 3 and TEC heat sink 12 must be kept flat. The thickness of thermal grease should be controlled within a reasonable range, and it should be applied evenly to avoid air bubbles and ensure thermal conductivity.

[0038] The copper thermal conductive plate 3 is 3-6mm thick and made of oxygen-free copper to improve thermal conductivity and ensure that the surface temperature uniformity of the BBO crystal 4 is ≤±0.2℃, which facilitates the accurate acquisition of temperature information by the platinum resistance temperature sensor 8.

[0039] Step (4): Fix the center positioning circular plate 10 on the center positioning circular plate mounting base through the center positioning circular plate pressure block, adjust the position of the center positioning circular plate 10 so that the laser is aligned with the center of the BBO crystal 4, and the small hole opened on the center positioning circular plate 10 matches the diameter of the pump light beam. This can not only achieve precise positioning of the pump light and ensure that the pump light is incident on the center of the BBO crystal 4, but also serve as a small aperture to filter stray light and improve the photon output quality.

[0040] The central positioning circular plate 10 is made of quartz glass, which has good light transmission performance and will not affect the transmission of pump light; alternatively, the central positioning circular plate 10 can be made of stainless steel. The diameter of the small hole it opens matches the diameter of the pump light beam, with a diameter error of ≤±0.01mm. The coaxiality between the center of the central positioning circular plate 10 and the center of the BBO crystal 4 is ≤±0.02mm, ensuring that the pump light can be accurately incident on the center of the BBO crystal 4. The central positioning circular plate clamping block is an elastic clamping block to avoid damage to the central positioning circular plate 10 during the clamping process, while ensuring that the central positioning circular plate 10 is firmly fixed and will not loosen. The central positioning circular plate mounting base can be finely adjusted up and down and left and right to facilitate precise alignment of the laser and the center of the BBO crystal 4.

[0041] Step (5): Fix the heat insulation shell 1 to the bottom adapter plate 2 with screws to ensure that the openings at both ends of the heat insulation shell 1 are precisely aligned with the positions of the BBO crystals 4, so as to avoid blocking the incident and outgoing pump light; install the bottom adapter plate 2 and the copper thermal conductive plate 3 above it, the heat insulation shell 1 and the central positioning circular plate mounting base on the linear module 13 as a whole. Connect the linear module 13 to the vacuum stepper motor 14, and debug the coordinated action of the vacuum stepper motor 14 and the linear module 13 to achieve smooth and fast switching of multiple BBO crystals 4. The switching positioning accuracy is ≤ ±0.003mm, which meets the requirements of wide-band phase matching tuning; the overall device structure design is adapted to the vacuum environment and can be used for high vacuum nonlinear optical experiments.

[0042] The insulation shell 1 is made of ceramic fiber with an aluminum foil reflective layer on the inner wall, providing excellent insulation performance, reducing heat loss, and lowering temperature control energy consumption. Alternatively, the insulation shell 1 can be made of polytetrafluoroethylene (PTFE) with a thickness of 2-5mm, with an aluminum foil reflective layer on the inner wall to further reduce heat loss and improve insulation performance. The linear module 13 uses a ball screw linear module with a positioning accuracy of ≤±0.003mm, ensuring smooth switching and precise positioning when multiple BBO crystals 4 are used.

[0043] Polytetrafluoroethylene (PTFE) material has excellent high temperature resistance and heat insulation properties, and is lightweight, so it will not increase the overall weight of the device; the aluminum foil reflective layer uses high reflectivity aluminum foil, which is laid flat and wrinkle-free, and can effectively reflect heat and reduce heat loss; the vacuum stepper motor 14 is a high-precision vacuum stepper motor with a speed adjustment range of 1-10 r / min, which can flexibly adjust the speed according to the crystal switching requirements to ensure a smooth, fast, and impact-free switching process and avoid damage to the BBO crystal 4.

[0044] In summary, by integrating multiple components, temperature control, angle tuning, stress tuning, and multi-channel switching functions into one unit, the three functions work together to improve tuning accuracy and efficiency. High-performance materials and high-precision components are selected to ensure the device's temperature control accuracy, angle adjustment accuracy, and switching accuracy. The optimized structural design makes the device adaptable to vacuum environments, broadening its application range. Through reasonable assembly processes, the synergy and stability of each component are ensured, extending the device's service life.

[0045] Each step in the method of this invention is complementary and indispensable. Step (1) realizes the installation and coarse angle adjustment of the BBO crystal 4, laying the foundation for subsequent fixation and tuning; Step (2) realizes the fixation and stress adjustment of the BBO crystal 4, while improving the uniformity of heat conduction; Step (3) realizes high-precision temperature control of the BBO crystal 4, ensuring that the crystal works within the required temperature range; Step (4) realizes precise positioning of the pump light, improving the photon output quality; Step (5) completes the assembly and debugging of the overall device, realizes multi-channel switching, and ensures that the device can operate normally. The design of each preferred scheme further optimizes the performance of the device and improves the tuning accuracy and stability.

[0046] The following specific example illustrates the concrete implementation of the above device.

[0047] like Figure 1 As shown, the present invention discloses an integrated angle-temperature-stress tuned multi-channel BBO crystal temperature control furnace design, comprising an insulating shell 1, a bottom adapter plate 2, a copper temperature-conducting plate 3, a BBO crystal 4, a crystal mounting base 5, a crystal pressing block 6, an indium sheet 7, a platinum resistance temperature sensor 8, a torque adjusting screw 9, a center positioning circular plate 10, a thermoelectric cooler (TEC) 11, a TEC heat sink 12, a linear module 13, and a vacuum stepper motor 14. The insulating shell 1 is made of polytetrafluoroethylene (PTFE) with a thickness of 3mm, and its inner wall is lined with an aluminum foil reflective layer. The openings at both ends have a diameter of 5mm, and their positions correspond to the mounting positions of the BBO crystal 4. The bottom adapter plate 2 is made of aluminum alloy with a thickness of 5mm and an anodized surface to enhance corrosion resistance. The copper temperature-conducting plate 3 is made of oxygen-free copper with a thickness of 3mm and a polished surface with a roughness ≤1.6μm. A small hole in the center is provided for mounting the platinum resistance temperature sensor 8. The BBO crystal 4 is selected with dimensions of 5mm × 5mm × 5mm. The crystal is a barium borate crystal; the crystal mounting base 5 is made of copper, with a 2mm diameter circular hole at the bottom and 2mm diameter U-shaped grooves at both ends; the crystal pressing block 6 is an L-shaped copper plate with a thickness of 3mm, and small holes with a diameter of 2mm are opened at the top and side ends; the indium sheet 7 is 0.1mm thick, and a thin layer of thermally conductive silicone grease is applied to the contact surface with the crystal pressing block before bonding; the platinum resistance temperature sensor 8 is a PT1000 model, with a probe diameter of 2mm and a length of 10mm; the torque adjusting screw 9 is an M1.6 screw that can be adjusted by a torque wrench to adjust the torque value, and the stress on the BBO crystal 4 can be adjusted by adjusting the torque value; the center positioning circular plate 10 is made of stainless steel with a thickness of 0.2mm, and has small holes with a diameter of 20μm, with a hole diameter error ≤±0.01mm; TEC 11 The temperature control range is 10℃ to 100℃, with a temperature control accuracy of ±0.01℃; the TEC heat sink 12 is made of aluminum alloy with a black anodized surface and heat dissipation fins with a thickness of 1mm and a spacing of 1mm; the linear module 13 adopts a ball screw linear module with a positioning accuracy of ±0.003mm; the vacuum stepper motor 14 is a high-precision stepper motor with a speed adjustment range of 1-10r / min.

[0048] like Figure 2 As shown, the phase-matching tuning method of the present invention includes the following steps:

[0049] Step (1): Perform surface treatment on the mating surface of the crystal mounting base 5 to ensure a roughness ≤ 1.6 μm. After cleaning, apply a thin layer of thermally conductive silicone grease (thermal conductivity 5.2 μm) to the mating surface. Place the BBO crystal 4 on the crystal mounting base 5, ensuring that the two sides of the BBO crystal 4 are in close contact with the crystal mounting base 5; fix the crystal mounting base 5 to the copper heat-conducting plate 3 with screws; use the round hole at the bottom and the U-shaped grooves at both ends of the crystal mounting base 5 to rotate and adjust the angle of the BBO crystal 4; monitor the output photon spot obtained by the low-light camera; adjust the incident angle of the pump light to a reasonable position; after adjustment, tighten the adjusting bolts and fix it with anti-slip washers to ensure angle stability.

[0050] Step (2): Attach 0.1mm thick indium sheets 7 to the upper and right end faces of the BBO crystal 4. Apply a thin layer of thermally conductive silicone grease to the contact surface between the indium sheets 7 and the crystal clamping block 6. Attach the L-shaped crystal clamping block 6 to the indium sheets 7. Mount the upper and side ends of the crystal clamping block 6 onto the crystal mounting base 5 using two stainless steel screws. Place elastic washers between the screws and the threaded holes of the crystal clamping block 6. Use a torque wrench to adjust the torque of the screws to 0.05. This achieves the fixation and stress tuning of BBO crystal 4, ensuring that BBO crystal 4 is subjected to uniform force and has no stress concentration.

[0051] Step (3): Apply a thin layer of thermal grease to the bottom of the copper thermal conductive plate 3, connect the two TEC 11 in series and attach them to the bottom of the copper thermal conductive plate 3, ensuring a tight fit and no air bubbles; install a platinum resistance temperature sensor 8 in the small hole in the middle of the copper thermal conductive plate 3 to collect the temperature data of the BBO crystal 4 in real time and feed it back to the temperature control system; apply a thin layer of thermal grease to the other end of the TEC 11, attach the TEC heat sink 12 to the TEC and fix it with screws, and set a shock-absorbing washer between the TEC heat sink 12 and the bottom adapter plate 2 to reduce the impact of vibration; adjust the temperature control function of the TEC 11, and adjust the working temperature of the BBO crystal 4 to 25℃ according to the feedback of the platinum resistance temperature sensor 8, and keep the temperature control accuracy at ±0.01℃.

[0052] Step (4): Fix the center positioning circular plate 10 on the center positioning circular plate mounting base by the center positioning circular plate pressure block, adjust the position of the center positioning circular plate 10 so that the light output center of the laser is aligned with the center of the BBO crystal 4, and ensure that the small hole on the center positioning circular plate 10 matches the diameter of the pump light beam to achieve precise positioning of the pump light and filtering of stray light.

[0053] Step (5): Fix the heat insulation shell 1 to the bottom adapter plate 2 with screws, ensuring that the openings at both ends of the heat insulation shell 1 are precisely aligned with the positions of the BBO crystals 4, without obstructing the incident and outgoing pump light; install the crystal mounting base 5, copper temperature conducting plate 3, TEC11, platinum resistance temperature sensor 8 and related components on the linear module 13, and connect the linear module 13 to the vacuum stepper motor 14; debug the coordinated action of the vacuum stepper motor 14 and the linear module 13 to achieve smooth switching of the 8 BBO crystals 4, with a switching positioning accuracy of ≤±0.003mm; place the entire device in a vacuum environment, debug the working status of each component, ensure that the feedback of the platinum resistance temperature sensor 8 is accurate, the temperature control of TEC 11 is stable, the device is operating normally, and achieve wide-band phase matching tuning.

[0054] In this embodiment, the temperature uniformity of the BBO crystal 4 is ±0.2℃, the angle adjustment accuracy is ±0.01°, and the stress adjustment accuracy is ±0.01°. The switching time between multiple crystals is ≤2s, and the temperature acquisition accuracy of the platinum resistance temperature sensor 8 is ≤±0.001℃, meeting the requirements for high-precision and high-efficiency phase matching tuning. The whole device operates stably in a vacuum environment, with excellent photon output quality, and can be widely used in laser frequency conversion experiments.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made by any person skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A multi-channel BBO crystal temperature control furnace with integrated angle-temperature-stress tuning, characterized in that, Includes an insulated outer shell (1), a bottom adapter plate (2), a copper thermal conductive plate (3), a BBO crystal (4), a crystal mounting base (5), a crystal pressing block (6), an indium sheet (7), a torque adjusting screw (9), a center positioning circular plate (10), a center positioning circular plate pressing block, a center positioning circular plate mounting base, a thermoelectric cooler (TEC) (11), a platinum resistance temperature sensor (8), a TEC heat sink (12), a linear module (13), and a vacuum stepper motor (14). The heat insulation shell (1) has openings at both ends and the opening positions correspond to the installation positions of the BBO crystal (4). The laser enters from one end through a small hole and exits from the other end through a small hole. The heat insulation shell (1) is fixed to the bottom adapter plate (2) by screws. The BBO crystal (4) is mounted on the crystal mounting base (5), the crystal mounting base (5) is mounted on the copper heat-conducting plate (3), and the crystal pressing block (6) is pressed and fixed to the BBO crystal (4) by the torque adjusting screw (9). The torque adjusting screw (9) is used to fix the BBO crystal (4) and also to adjust the mechanical stress on the BBO crystal (4). The crystal pressing block (6) has a threaded hole, and the micro-angle adjustment of a single BBO crystal (4) can be realized after the screw is installed. The central positioning circular plate (10) is installed on the central positioning circular plate mounting base, which is installed on the bottom adapter plate (2) and fixed by the central positioning circular plate pressure block. It is used for center alignment of the laser and the BBO crystal (4). The small hole it opens also serves as an aperture. The bottom end of the copper thermal plate (3) is attached to a TEC (11), and a small hole is provided in the middle to install a platinum resistance temperature sensor (8). Thermal grease is applied to the contact surfaces of the TEC (11) with the copper thermal plate (3) and the TEC heat sink (12). The TEC (11) is attached and fixed to the TEC heat sink (12). The linear module (13) is connected to the vacuum stepper motor (14). The bottom adapter plate (2) and the copper heat-conducting plate (3), the heat-insulating shell (1) and the central positioning circular plate mounting base are installed on the linear module (13) to realize the switching of multiple BBO crystals (4).

2. The integrated angle-temperature-stress tuned multi-channel BBO crystal temperature control furnace as described in claim 1, characterized in that, The crystal mounting base (5) is made of copper and fixed on the copper thermal plate (3). The bottom of the crystal mounting base (5) is provided with a round hole, which, together with the U-shaped grooves at both ends, enables the rotation adjustment of the BBO crystal (4), thereby adjusting the incident angle of the pump photon. The surface roughness of the crystal mounting base (5) is ≤0.8μm.

3. The multi-channel BBO crystal temperature control furnace with integrated angle-temperature-stress tuning as described in claim 1, characterized in that, A thin layer of thermal grease is applied to the mating surfaces of the BBO crystal (4) and the crystal mounting base (5). The thermal conductivity of the thermal grease is ≥ .

4. The multi-channel BBO crystal temperature control furnace with integrated angle-temperature-stress tuning as described in claim 1, characterized in that, The crystal mounting base (5) is an L-shaped mounting base, and the crystal clamping block (6) is made of an L-shaped copper plate. Small holes are opened on the upper end and side end face of the crystal clamping block (6). The crystal clamping block (6) and the crystal mounting base (5) are mounted on the crystal mounting base (5) in opposite directions by two torque adjusting screws (9). An indium sheet (7) is placed on the contact surface between the crystal clamping block (6) and the BBO crystal (4). The thickness of the indium sheet (7) is 0.1-0.2mm. A thin layer of thermally conductive silicone grease is applied to the contact surface between the indium sheet (7) and the crystal clamping block (6).

5. The multi-channel BBO crystal temperature control furnace with integrated angle-temperature-stress tuning as described in claim 4, characterized in that, The torque adjusting screw (9) is made of stainless steel, and an elastic washer is provided between the torque adjusting screw (9) and the threaded hole of the crystal pressure block (6); the torque adjustment range of the torque adjusting screw (9) is 0-0.

2. .

6. The multi-channel BBO crystal temperature control furnace with integrated angle-temperature-stress tuning as described in claim 1, characterized in that, Two TECs (11) connected in series are attached to the bottom of the copper heat-conducting plate (3), and the other end of the TEC (11) is attached and fixed to the TEC heat sink (12); the TEC (11) adopts a bidirectional temperature-controlled thermoelectric cooler with a temperature control range of 10℃ to 100℃ and a temperature control accuracy of ≤±0.01℃.

7. The multi-channel BBO crystal temperature control furnace with integrated angle-temperature-stress tuning as described in claim 6, characterized in that, The TEC radiator (12) is made of aluminum alloy and has heat dissipation fins on its surface. The thickness of the heat dissipation fins is 1-4mm and the spacing between adjacent fins is 1-2mm. The copper heat conduction plate (3) is 3-6mm thick and is made of oxygen-free purple copper.

8. The integrated angle-temperature-stress tuned multi-channel BBO crystal temperature control furnace as described in claim 1, characterized in that, The central positioning circular plate (10) is made of stainless steel. The diameter of the small hole it opens matches the diameter of the pump light beam. The diameter error of the small hole is ≤ ±0.01mm. The coaxiality between the center of the central positioning circular plate (10) and the center of the BBO crystal (4) is ≤ ±0.02mm, ensuring that the pump light is accurately incident on the center of the crystal.

9. The integrated angle-temperature-stress tuned multi-channel BBO crystal temperature control furnace as described in claim 1, characterized in that, The heat insulation shell (1) is made of polytetrafluoroethylene with a thickness of 2-5mm. The inner wall of the heat insulation shell (1) is covered with an aluminum foil reflective layer. The linear module (13) adopts a ball screw linear module with a positioning accuracy of ≤±0.003mm.

10. The integrated angle-temperature-stress tuned multi-channel BBO crystal temperature control furnace as described in claim 1, characterized in that, The vacuum stepper motor (14) is a high-precision vacuum stepper motor with a speed adjustment range of 1-10 r / min.

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