Optical reference cavity system capable of precisely controlling temperature in large temperature zone

Abstract

The embodiment of the invention discloses an optical reference cavity system for precise temperature control in a large temperature zone. According to the optical reference cavity system, active thermal control and passive thermal control are combined to realize large-temperature-zone precise temperature control of the high-precision optical reference cavity system, and the large-range temperature negative deviation condition that the zero-expansion temperature point of the optical reference cavity made of the heterogeneous material is far lower than the room temperature can be fully dealt with. According to the optical reference cavity, the technical problem that precise temperature control is difficult to realize due to the fact that the cavity body and the cavity mirror of the optical reference cavity are combined through optical cement made of heterogeneous materials and the overall zero-expansion temperature point is obviously lower than the room temperature is solved, and high-precision temperature control of the optical reference cavity in a large-temperature area is achieved; and therefore, the high-temperature-resistant high-temperature-resistant cable can stably work near an overall zero-expansion temperature point which is far lower than room temperature.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and in particular to an optical reference cavity system with precise temperature control over a large temperature range. Background Art

[0002] Ultra-stable narrow-linewidth single-frequency lasers have excellent temporal coherence and play a vital role in applications such as optical frequency standards, ultra-stable microwave signal generation, and coherent optical frequency transmission. The ultra-high temporal coherence of this laser system stems from the Fabry-Perot high-precision optical reference cavity integrated in the system. The cavity material is usually ultra-low thermal expansion (ULE) glass, and the cavity mirror material can be ultra-low thermal expansion (ULE) glass or fused quartz. Although ULE materials are used as the whole, precise temperature control is still required to keep the high-precision optical reference cavity near its zero expansion temperature point to reduce the sensitivity of the optical reference cavity to temperature fluctuations.

[0003] For a 20-30 cm long optical reference cavity, in order to give full play to the low background thermal noise performance of the long cavity and to achieve the adaptation of the thermal noise performance indicators of the cavity and the cavity mirror, the cavity mirror material needs to be selected from fused quartz material. However, after the cavity and cavity mirror are combined with heterogeneous optical glue, the overall zero expansion temperature point will significantly deviate from the zero expansion temperature point of the original cavity part, usually reaching a negative deviation of 20-30°C, thereby moving the overall zero expansion temperature point to 0-10°C, which is much lower than room temperature, which is not conducive to the implementation of precise temperature control.

[0004] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0005] The embodiment of the present application provides an optical reference cavity system with precise temperature control over a large temperature range, so as to at least solve the technical problem that the overall zero expansion temperature point of the optical reference cavity is significantly lower than the room temperature due to the combination of heterogeneous material optical glue used for the cavity and cavity mirror of the optical reference cavity, making it difficult to achieve precise temperature control.

[0006] According to one aspect of an embodiment of the present application, an optical reference cavity system with precise temperature control over a large temperature range is provided, comprising: an optical reference cavity, a vacuum cavity, a multi-layer heat shielding structure, a water-cooled plate, a semiconductor refrigeration sheet, a heating foil and a temperature sensor; wherein: the optical reference cavity is placed in a vacuum cavity, and the multi-layer heat shielding structure is arranged between the vacuum cavity and the optical reference cavity; the water-cooled plate is arranged on the bottom surface of the vacuum cavity, and the water-cooled plate is used to control the temperature through water circulation inside it; the semiconductor refrigeration sheet is arranged between the bottom surface of the vacuum cavity and the water-cooled plate, the cold surface of the semiconductor refrigeration sheet contacts the bottom surface of the vacuum cavity, and the hot surface of the semiconductor refrigeration sheet contacts the water-cooled plate, and the semiconductor refrigeration sheet is used to perform bidirectional temperature control on an object contacted by its cold surface by connecting a controlled bidirectional current; the heating foil is attached to the outer side of the outermost heat shielding layer in the vacuum cavity, and the temperature sensor is arranged at the center position of each surface of the outermost heat shielding layer, and the heating foil is used to perform unidirectional heating and temperature control through feedback from the temperature sensor.

[0007] Optionally, the optical reference cavity is connected to the multi-layer heat shielding structure via a plurality of spherical support members, and the multi-layer heat shielding structure is connected to the vacuum cavity via a plurality of support columns.

[0008] Optionally, the multi-layer heat shielding structure includes a plurality of heat shielding layers, and two adjacent heat shielding layers are connected via a plurality of support columns.

[0009] Optionally, a water flow channel is provided inside the water cooling plate, and two connectors connected to water hoses are provided on the side. The water cooler is connected to the water cooling plate through the water hoses to form a water flow circulation.

[0010] Optionally, it also includes: a temperature controller, which is connected to the heating foil and the temperature sensor respectively, and is used to control the heating foil to heat the multi-layer heat shielding structure and the optical reference cavity in the vacuum cavity which are below the zero expansion temperature point based on the temperature collected by the temperature sensor.

[0011] Optionally, the temperature set by the temperature controller is the zero expansion temperature of the optical reference cavity.

[0012] Optionally, it also includes: an ion pump, which is connected to the vacuum chamber and is used to extract gas molecules in the vacuum chamber to maintain an ultra-high vacuum environment in the vacuum chamber.

[0013] Optionally, it further includes: an optical platform, wherein the vacuum chamber is arranged on the optical platform, the upper surface of the optical platform contacts the bottom surface of the water-cooling plate, and the water-cooling plate is connected to the vacuum chamber through a plurality of support blocks.

[0014] In the embodiment of the present application, the optical reference cavity system adopts a combination of active and passive thermal control to achieve precise temperature control of a high-precision optical reference cavity system over a large temperature range, which can fully cope with the large range of negative temperature deviations where the zero expansion temperature point of the heterogeneous material optical reference cavity is far below room temperature. It not only effectively expands the temperature control range of the optical reference cavity system, but also has high-precision temperature control performance, laying a technical foundation for the development of ultra-stable narrow-linewidth lasers integrating longer heterogeneous high-precision optical reference cavities, thereby solving the technical problem that the overall zero expansion temperature point of the optical reference cavity is significantly lower than room temperature due to the combination of heterogeneous material optical glue for the cavity and cavity mirrors of the optical reference cavity, making it difficult to achieve precise temperature control. This achieves high-precision temperature control of the optical reference cavity in a large temperature range, so that the technical effect of stably operating near the overall zero expansion temperature point far below room temperature is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 A schematic diagram of an optical reference cavity system with precise temperature control over a large temperature range provided in an embodiment of the present application;

[0017] Figure 2 A schematic diagram of water-cooled active temperature control provided in an embodiment of the present application;

[0018] Figure 3 Schematic diagram of one-way heating and temperature control of the heating foil provided in an embodiment of the present application.

[0019] The above drawings include the following reference numerals:

[0020] 10. Optical window; 11. Optical reference cavity; 12. Vacuum cavity; 13. Multi-layer heat shielding structure; 14. Water cooling plate; 15. Semiconductor cooling sheet; 16. Heating foil; 17. Temperature sensor; 18. Ion pump; 19. Optical platform; 20. Water cooler; 21. Temperature controller; a. Sphere support; b. Support column; c. Support block. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] According to one aspect of the embodiments of the present application, an optical reference cavity system with precise temperature control over a large temperature range is provided. Figure 1 A schematic diagram of an optical reference cavity system with precise temperature control over a large temperature range provided in an embodiment of the present application, such as Figure 1 As shown, the optical reference cavity system includes: an optical reference cavity 11, a vacuum cavity 12, a multi-layer heat shielding structure 13, a water cooling plate 14, a semiconductor cooling sheet 15, a heating foil 16 and a temperature sensor 17. The optical reference cavity system is described in detail below.

[0024] The optical reference cavity 11 is placed in the vacuum cavity 12, and a multi-layer heat shielding structure 13 is arranged between the vacuum cavity 12 and the optical reference cavity 11;

[0025] A water cooling plate 14 is provided on the bottom surface of the vacuum chamber 12, and the water cooling plate 14 is used to control the temperature through water circulation inside the water cooling plate 14;

[0026] A semiconductor cooling sheet 15 is provided between the bottom surface of the vacuum chamber 12 and the water cooling plate 14. The cold surface of the semiconductor cooling sheet 15 contacts the bottom surface of the vacuum chamber 12, and the hot surface of the semiconductor cooling sheet 15 contacts the water cooling plate 14. The semiconductor cooling sheet 15 is used to perform bidirectional temperature control on an object contacted by its cold surface by connecting a controlled bidirectional current.

[0027] The outer side of the outermost heat shielding layer in the vacuum chamber 12 is covered with a heating foil 16 , and a temperature sensor 17 is provided at the center of each surface of the outermost heat shielding layer. The heating foil 16 is used for unidirectional heating and temperature control through feedback from the temperature sensor 17 .

[0028] In the embodiment of the present application, the optical reference cavity system adopts a combination of active and passive thermal control to achieve precise temperature control of a high-precision optical reference cavity system over a large temperature range, which can fully cope with the large range of negative temperature deviations where the zero expansion temperature point of the heterogeneous material optical reference cavity is far below room temperature. It not only effectively expands the temperature control range of the optical reference cavity system, but also has high-precision temperature control performance, laying a technical foundation for the development of ultra-stable narrow-linewidth lasers integrating longer heterogeneous high-precision optical reference cavities, thereby solving the technical problem that the overall zero expansion temperature point of the optical reference cavity is significantly lower than room temperature due to the combination of heterogeneous material optical glue for the cavity and cavity mirrors of the optical reference cavity, making it difficult to achieve precise temperature control. This achieves high-precision temperature control of the optical reference cavity in a large temperature range, so that the technical effect of stably operating near the overall zero expansion temperature point far below room temperature is achieved.

[0029] Optionally, by connecting a controlled bidirectional current to the semiconductor refrigeration sheet, bidirectional temperature control of the object in contact with its cold surface can be achieved. The semiconductor refrigeration sheet acts as a bidirectional heat conduction channel between the vacuum cavity and the water-cooled plate, thereby forming a temperature difference between the two. In order to cope with the significant negative deviation of the overall zero expansion temperature point from room temperature caused by the heterogeneous optical glue of the above-mentioned cavity and the cavity mirror, it is usually necessary to cool the vacuum cavity and reduce it to below the zero expansion temperature point of the optical reference cavity. The cooling temperature of the vacuum cavity is different depending on the cooling power of the semiconductor refrigeration sheet and the output electrical power of its driver, as well as the mass of the vacuum cavity being cooled. Usually, for a vacuum cavity that accommodates a 30 cm long optical reference cavity and contains three layers of heat shielding, a cooling effect of the vacuum cavity in the range of -5°C to 0°C can be achieved.

[0030] like Figure 1 As shown, the optical reference cavity 11 is connected to the multilayer heat shielding structure 13 through multiple spherical support members a, and the multilayer heat shielding structure 13 is connected to the vacuum cavity 12 through multiple support columns a. The multilayer heat shielding structure 13 includes multiple heat shielding layers, and two adjacent heat shielding layers are connected by multiple support columns b. The optical reference cavity 11 includes a cavity 1101, a cavity mirror 1102 and a fluororubber hemisphere 1103. Two optical windows 10 are provided on the side of the vacuum cavity 12.

[0031] The spherical support a includes but is not limited to ultra-low thermal expansion glass spheres. The support column b includes but is not limited to ultra-low thermal expansion glass cylinders. The number of thermal shielding layers in the multi-layer thermal shielding structure 13 can be three or more.

[0032] The cavity 1101 is the main structural part of the optical reference cavity and is usually made of ultra-low thermal expansion (ULE) glass to ensure that it maintains extremely high dimensional stability when the temperature changes. The cavity is the basis of a high-precision optical resonator and provides a precise optical path inside for reflecting and enhancing light waves of a specific frequency.

[0033] The cavity mirrors 1102 are located at both ends of the cavity 1101, and are usually made of fused quartz because this material has low thermal noise characteristics at low temperatures. The cavity mirrors are used to reflect light waves and form a stable optical resonant cavity together with the cavity. The cavity mirrors are bonded to the cavity through optical glue, but due to the different thermal expansion coefficients of the two materials, a negative deviation of the overall zero expansion temperature point will occur.

[0034] The fluororubber hemisphere 1103 has good chemical corrosion resistance and elasticity, and can maintain stable performance in high and low temperature environments. In this specific application, it is used to seal the optical reference cavity to prevent external contaminants from entering, or as a flexible support to reduce the impact of mechanical vibration on the optical reference cavity.

[0035] The vacuum chamber 12 provides an ultra-high vacuum environment for the optical reference cavity, reduces the interference of gas molecules on the optical path, and reduces the influence of heat conduction and heat radiation. A multi-layer heat shielding structure is set inside the vacuum chamber to further isolate the external temperature fluctuations and ensure the temperature stability of the optical reference cavity.

[0036] The two optical windows 10 are arranged on the sides of the vacuum cavity 12 to introduce and remove the laser light from the optical reference cavity 11. The optical windows must have high light transmittance and be able to withstand the pressure difference in the vacuum environment. They are usually made of materials with low absorption and low scattering properties, such as fused quartz or sapphire, to ensure high-quality transmission of laser signals.

[0037] The heat shield is an effective way to reduce the impact of temperature fluctuations and can extend the response time constant of the optical reference cavity to ambient temperature fluctuations. In a vacuum environment, heat transfer can only be achieved through conduction and radiation. The heat shield is equivalent to an energy storage unit in the heat transfer path between the vacuum cavity and the optical reference cavity, acting as a low-pass filter in the heat transfer process, suppressing high-frequency temperature fluctuations.

[0038] Since the optical reference cavity is placed in a vacuum chamber, the influence of thermal convection can be ignored. The modes of heat transfer between the optical reference cavity and the heat shielding layer mainly include thermal radiation and heat conduction, and their characteristics are similar to the charging and discharging characteristics of a capacitor (RC) integration circuit, that is, the thermal resistance and thermal capacity are similar to the resistance and capacitance in the RC integration circuit. An equivalent multi-stage RC integration circuit can be used to establish a model for the response of the optical reference cavity's temperature to changes in the external ambient temperature.

[0039] According to the thermal radiation model, when the temperature of object i rises, heat radiates from object i to object j, and the thermal resistance is Where: R ij is the thermal radiation coefficient, which is related to the thermal radiation rate and the radiation angle; σ is the Stefan-Boltzmann constant, σ=5.67×10 -8 W·m -2 ·K-4 ; A j and T 0 are the surface area and initial temperature of object j respectively. When both object i and object j are cylinders, the thermal radiation coefficient β ij =1 / ε j +(1-ε i ) / ε i × j / r i , where ε is the thermal emissivity and r is the radius of the cylinder.

[0040] In addition to thermal radiation, there is also heat conduction because there are support columns between the layers in the optical reference cavity system for mechanical fixation and connection. Similarly, when the temperature of object i increases and heat is conducted from object i to object j, the thermal resistance associated with heat conduction is expressed as r ij =L / (kA), where L and A are the height and area of ​​the support column respectively, and k is the thermal conductivity of the support column.

[0041] Since heat is transferred by thermal radiation and thermal conduction at the same time, it is similar to two resistors in parallel in a circuit, so the thermal resistance after parallel connection is Z ij =R ij ·r ij / (R ij +r ij ). The heat capacity Q of object j j =m j ·C j , where m j and C j are the mass and specific heat capacity of object j respectively. When the temperature of object i changes, object j changes at τ ij The temperature changes during this time, τ ij It is also called the time constant τ of object j under the action of object i ij =Z ij ·C j .

[0042] According to the heat exchange physical model, when the temperature of the vacuum chamber T v When the temperature of the three-layer heat shielding layer T s1 、T s2 、T s3 and the temperature of the optical reference cavity T c The change over time can be expressed by the differential equation:

[0043]

[0044] Among them, τ v-s1 is the time constant of the first heat shielding layer under the heat exchange of the vacuum chamber, τ s2-s1is the time constant of the first heat shielding layer under the heat exchange effect of the second heat shielding layer, τ s1-s2 is the time constant of the second heat shield under the heat exchange effect of the first heat shield, τ s3-s2 is the time constant of the second heat shielding layer under the heat exchange effect of the third heat shielding layer, τ s2-s3 is the time constant of the third heat shield under the heat exchange of the second heat shield, τ c-s3 is the time constant of the third heat shield under the heat exchange of the optical reference cavity, τ s3-c is the time constant of the optical reference cavity under the heat exchange of the third heat shielding layer. Substituting the design parameters into the above formula, the temperature T of the optical reference cavity can be obtained by numerical calculation. c By optimizing the parameters related to the shielding layer structure, a reasonable multi-layer heat shielding structure design can be obtained.

[0045] Usually, the heat shielding layer is made of materials with large heat capacity and low surface thermal emissivity, and its surface is polished and then plated with a layer of gold or silver with lower thermal emissivity to increase thermal resistance and reduce heat transfer efficiency.

[0046] In the embodiments of the present application, by providing a multi-layer heat shielding structure, a low-pass filter response mechanism for temperature changes between the vacuum cavity and the optical reference cavity can be implemented to effectively reduce the impact of external ambient temperature changes on the temperature of the optical reference cavity in the vacuum cavity.

[0047] As an optional embodiment, a water flow channel is provided inside the water cooling plate 14, and two connectors connected to water hoses are provided on the side. The water cooler is connected to the water cooling plate 14 through the water hoses to form a water flow circulation.

[0048] Optionally, a water cooling plate is arranged on the bottom surface of the vacuum chamber, and an actively controlled semiconductor cooling plate is inserted between the two, with its cold surface in contact with the bottom surface of the vacuum chamber and its hot surface in contact with the water cooling plate. Active water cooling temperature control is used to quickly conduct away and dissipate the heat on the hot surface of the semiconductor cooling plate, and avoid continuous accumulation of heat in the semiconductor cooling plate.

[0049] Figure 2 A schematic diagram of water-cooled active temperature control provided in an embodiment of the present application, such as Figure 2 As shown, the water-cooled plate 14 has a machined water flow channel inside, and two joints connected to the water hose are provided on its side. The two joints are completely equivalent; when one of them is selected as the water inlet joint, the other becomes the water outlet joint. The water cooler 20 is connected to the water-cooled plate 14 through the water hose to form a water flow circulation; the water cooler 20 cools the circulating water and pumps it out to the water-cooled plate 14; the water flow takes away the heat of the water-cooled plate, thereby cooling the water-cooled plate, and then flows downstream to the water cooler 20, thereby realizing a water cooling cycle. According to the cooling power of the water cooler 20, a cooling effect of the water-cooled plate in the range of -10°C to 0°C can be achieved.

[0050] As an optional embodiment, it further includes: a temperature controller 20, which is connected to the heating foil and the temperature sensor 17 respectively, and is used to control the heating foil 16 to heat the multilayer heat shielding structure 13 and the optical reference cavity 11 in the vacuum cavity 12 which are below the zero expansion temperature point based on the temperature collected by the temperature sensor 17. The temperature set by the temperature controller 20 is the zero expansion temperature of the optical reference cavity.

[0051] Figure 3 A schematic diagram of one-way heating and temperature control of the heating foil provided in the embodiment of the present application, as shown in FIG. Figure 3 As shown, the heating foil 16 is attached to the outer side of the outermost heat shielding layer in the vacuum chamber 12, and is used to heat the multi-layer heat shielding structure 13 and the optical reference cavity 11 in the vacuum chamber 12, which are below the zero expansion temperature. A temperature sensor 17 is set at the center of each surface of the heat shielding layer, which forms a one-way heating temperature control loop with the heating foil 16 and the temperature controller 20. The temperature setting temperature is the zero expansion temperature of the optical reference cavity 11.

[0052] Since the heat shield is in a vacuum insulation environment, the temperature control loop composed of the thermostat, heating foil, and temperature sensor does not need to consume much power, usually only about 3W, to achieve heating within the heat shield within the range of 0°C to +25°C. Moreover, compared with semiconductor refrigeration sheets, heating foil can achieve more precise temperature control.

[0053] In the embodiments of the present application, high-precision temperature control can be achieved at a temperature below room temperature by using an active temperature control method using a heating foil for unidirectional heating.

[0054] like Figure 1 As shown, the optical reference cavity system further includes: an ion pump 18 , which is connected to the vacuum cavity 12 and is used to extract gas molecules in the vacuum cavity 12 to maintain an ultra-high vacuum environment in the vacuum cavity 12 .

[0055] The ion pump can extract the gas molecules in the vacuum chamber to reach and maintain an extremely low pressure level. This ultra-high vacuum environment is crucial to reducing the interference of gas molecules on the optical path in the optical reference cavity, ensuring the stability and accuracy of the optical path. In an ultra-high vacuum, the number of gas molecules is extremely small, so there is almost no heat conduction through gas molecules. This helps to reduce the impact of external temperature fluctuations on the optical reference cavity, making the multi-layer heat shield structure and other temperature control measures more effective.

[0056] Ion pumps can not only extract gas molecules, but also adsorb or capture tiny particles and chemical pollutants such as water vapor and oil mist remaining in the vacuum chamber. If these pollutants exist near the optical reference cavity, they may be deposited on the surface of the optical element and affect its performance. By using ion pumps, the optical elements can be kept clean and the long-term stable operation of the system can be ensured. In an ultra-high vacuum environment, heat transfer is mainly carried out through thermal radiation and solid contact conduction.

[0057] like Figure 1 As shown, the optical reference cavity system also includes: an optical platform 19, wherein the vacuum cavity 12 is arranged on the optical platform 19, the upper surface of the optical platform 19 contacts the bottom surface of the water-cooled plate 14, and the water-cooled plate 14 is connected to the vacuum cavity 12 through a plurality of support blocks c.

[0058] The optical platform serves as the base of the entire system and provides stable support. The platform needs to have good mechanical and thermal stability to reduce the impact of external vibration and temperature changes on the system. The vacuum chamber is set on the optical platform, which contains multiple layers of heat shielding and a high-precision optical reference cavity. The vacuum chamber provides a low-noise, stable environment for the optical reference cavity to avoid interference from external factors (such as air flow and temperature fluctuations). The water-cooled plate is located below the vacuum chamber, and its bottom surface is in direct contact with the upper surface of the optical platform. The function of the water-cooled plate is to quickly conduct the heat generated by the semiconductor refrigeration plate through the internal water flow channel to maintain a low-temperature environment. The support block is used to connect the water-cooled plate and the vacuum chamber to ensure close contact between the two, and at the same time play a mechanical support role. The support block material should be selected from materials with good thermal conductivity and high mechanical strength.

[0059] In the embodiments of the present application, active and passive thermal control methods are adopted, and a multi-layer heat shielding structure is used to suppress temperature fluctuations and increase the heat transfer response time; water-cooled active temperature control, semiconductor refrigeration plate two-way active temperature control, and heating foil unidirectional heating temperature control are set, and the temperature is first lowered and then raised from the outside to the inside, giving full play to the temperature control technical advantages of semiconductor refrigeration plates and heating foils, and comprehensively realizing the large temperature range precision temperature control requirements that can adapt to longer heterogeneous high-precision optical reference cavities.

[0060] Experimental tests have shown that the semiconductor refrigeration sheet assisted by the water-cooled plate can reduce the temperature of the vacuum chamber by more than 10 degrees Celsius compared to the surrounding environment. For a multi-layer heat shielding structure adapted to a 30-centimeter-long high-precision optical reference cavity, the heat transfer response time constant can be greater than 10 days.

[0061] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0062] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0063] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0064] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0065] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0066] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0067] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An optical reference cavity system with precise temperature control over a large temperature range, characterized in that: include: An optical reference cavity (11), a vacuum cavity (12), a multi-layer heat shielding structure (13), a water cooling plate (14), a semiconductor cooling sheet (15), a heating foil (16) and a temperature sensor (17); wherein: The optical reference cavity (11) is placed in a vacuum cavity (12), and the multi-layer heat shielding structure (13) is arranged between the vacuum cavity (12) and the optical reference cavity (11); The bottom surface of the vacuum chamber (12) is provided with the water cooling plate (14), and the water cooling plate (14) is used to control the temperature through water circulation inside the water cooling plate (14); The semiconductor refrigeration sheet (15) is arranged between the bottom surface of the vacuum chamber (12) and the water-cooling plate (14); the cold surface of the semiconductor refrigeration sheet (15) contacts the bottom surface of the vacuum chamber (12), and the hot surface of the semiconductor refrigeration sheet (15) contacts the water-cooling plate (14); the semiconductor refrigeration sheet (15) is used to perform bidirectional temperature control on an object in contact with its cold surface by connecting a controlled bidirectional current; The outer side of the outermost heat shielding layer in the vacuum chamber (12) is covered with the heating foil (16), and the temperature sensor (17) is arranged at the center position of each surface of the outermost heat shielding layer. The heating foil (16) is used to perform unidirectional heating and temperature control through feedback from the temperature sensor (17).

2. The optical reference cavity system according to claim 1, characterized in that: The optical reference cavity (11) is connected to the multi-layer heat shielding structure (13) via a plurality of spherical support members (a), and the multi-layer heat shielding structure (13) is connected to the vacuum cavity (12) via a plurality of support columns (b).

3. The optical reference cavity system according to claim 1, characterized in that: The multi-layer heat shielding structure (13) comprises a plurality of heat shielding layers, and two adjacent heat shielding layers are connected via a plurality of support columns (b).

4. The optical reference cavity system according to claim 1, characterized in that: The water cooling plate (14) is provided with a water flow channel inside and two joints connected to water hoses are provided on the side. The water cooling machine (20) is connected to the water cooling plate (14) through the water hoses to form a water flow circulation.

5. The optical reference cavity system according to claim 1, characterized in that: Also includes: A temperature controller (21) is connected to the heating foil (16) and the temperature sensor (17) respectively, and is used to control the heating foil (16) based on the temperature collected by the temperature sensor (17) to heat the multi-layer heat shielding structure (13) and the optical reference cavity (11) in the vacuum cavity (12) at a temperature point below the zero expansion temperature.

6. The optical reference cavity system according to claim 5, characterized in that: The temperature set by the temperature controller (21) is the zero expansion temperature of the optical reference cavity (11).

7. The optical reference cavity system according to claim 1, characterized in that: Also includes: An ion pump (18) is connected to the vacuum chamber (12) and is used to extract gas molecules in the vacuum chamber (12) to maintain an ultra-high vacuum environment in the vacuum chamber (12).

8. The optical reference cavity system according to any one of claims 1 to 7, characterized in that: Also includes: An optical platform (19), wherein the vacuum chamber (12) is arranged on the optical platform (19), the upper surface of the optical platform (19) contacts the bottom surface of the water-cooling plate (14), and the water-cooling plate (14) is connected to the vacuum chamber (12) via a plurality of support blocks (c).

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