Compatible cavity-enhanced optical lattice cold cavity device and atomic optical clock

Abstract

The application provides a cold cavity device compatible with a cavity-enhanced optical lattice and an atomic optical clock, and the cold cavity device comprises: a cold cavity arranged in the interior of a vacuum cavity, and a containing space in the cold cavity is used for containing atoms; a cold source used for keeping the temperature of the cold cavity at a target temperature; a cavity-enhanced structure comprising a first cavity mirror part and a second cavity mirror part, the first cavity mirror part comprises a first cavity mirror and a first adapter ring, the second cavity mirror part comprises a second cavity mirror and a second adapter ring, the first cavity mirror part is fixed at a position corresponding to a first shell window of the vacuum cavity, the second cavity mirror part is fixed at a position corresponding to a second shell window of the vacuum cavity, and the first shell window and the second shell window are opposite to each other; a first extension part on the shell of the cold cavity is opposite to the first cavity mirror part, and a second extension part is opposite to the second cavity mirror part, so that lattice light incident to the cold cavity through the cavity-enhanced structure is reflected and enhanced between the first cavity mirror and the second cavity mirror, and continuously locked at a magic frequency to obtain a stable optical lattice.

Description

Technical Field

[0001] This invention relates to the fields of optical elements, optical systems, quantum optics, and atomic optical frequency standards, and particularly to a cold cavity device for a cavity-compatible enhanced optical lattice and an atomic optical clock. Background Technology

[0002] Currently, the most advanced optical frequency standard system has an uncertainty that is more than two orders of magnitude lower than the cesium microwave frequency standard, which is the current international standard for defining the second. Therefore, the optical frequency standard is expected to become the new standard for defining the second in the near future and will play an important role in fields such as satellite navigation, geodesy, gravitational wave detection, and dark matter detection. However, factors such as electric fields, cold collisions between atoms within the cold cavity, and background gas collisions can all cause shifts in the clock transition frequency of optical clocks. Current cold cavity devices are still insufficient to meet these requirements, thus limiting further improvements in the accuracy of optical clocks. Summary of the Invention

[0003] In view of the above, in order to at least partially solve at least one of the aforementioned technical problems, the present invention provides a cold cavity device and an atomic optical clock with a compatible cavity-enhanced optical lattice, the technical solution of which is as follows:

[0004] According to one embodiment of the present invention, a cold cavity device compatible with cavity-enhanced optical lattices is provided, comprising a cold cavity, a vacuum cavity, an atomic source, a cold source, and a cavity enhancement structure. The cold cavity is located inside the vacuum cavity. The cold cavity includes a shell and a receiving space inside the shell. The shell of the cold cavity is provided with multiple laser incident windows. The receiving space inside the cold cavity is used to accommodate atoms input by the atomic source. The cold source is used to maintain the temperature of the cold cavity at the target temperature. The cavity enhancement structure includes a first cavity mirror part and a second cavity mirror part. The first cavity mirror part includes a first cavity mirror and a first adapter ring. The second cavity mirror part includes a second cavity mirror and a second adapter ring. The first cavity mirror part is fixed to the position opposite to the first shell window of the vacuum cavity through the first adapter ring. The second cavity mirror part is fixed to the position opposite to the second shell window of the vacuum cavity through the second adapter ring. The first shell window and the second shell window are positioned opposite each other. The shell of the cold cavity is also provided with a hollow tubular first extension and a second extension. The first extension is directly opposite to the first cavity mirror part, and the second extension is directly opposite to the second cavity mirror part. This allows the lattice light incident into the cold cavity through the cavity enhancement structure to be reflected and enhanced between the first cavity mirror and the second cavity mirror, and continuously locked at the magic frequency to obtain a stable optical lattice.

[0005] According to an embodiment of the present invention, the first cavity mirror part further includes a copper ring and a piezoelectric ceramic ring disposed between the first cavity mirror and the first adapter ring, such that the first cavity mirror, the copper ring, the piezoelectric ceramic ring and the first adapter ring are sequentially fitted together; the extension and contraction of the piezoelectric ceramic ring is adjusted by adjusting the voltage applied to the piezoelectric ceramic ring so that the distance between the first cavity mirror and the second cavity mirror remains stable.

[0006] According to an embodiment of the present invention, the internal mirrors of the first and second cavity mirrors are coated with reflective films, and the reflective films have a reflectivity of not less than 99.9% for lattice light wavelengths; the inner wall surface of the shell of the cold cavity is coated with a black coating to absorb external heat radiation entering the cold cavity, while reducing the reflectivity of heat radiation inside the cold cavity and reducing stray heat radiation reflected to the atomic positions.

[0007] According to an embodiment of the present invention, the solid angle of external thermal radiation entering the cold cavity through the first extension and the second extension is compressed by configuring the ratio of the length to the inner diameter of the first extension and the second extension.

[0008] According to an embodiment of the present invention, the copper ring is electrically connected to the housing of the vacuum cavity via a wire to conduct away the static charge accumulated on or inside the piezoelectric ceramic ring, so as to prevent the charge from being conducted to the first cavity mirror and causing DC Stark frequency shift.

[0009] According to an embodiment of the present invention, the cold source is connected to the cold cavity through a flexible cold chain to suppress the transmission of mechanical vibration of the cold source to the cold cavity while conducting cold energy.

[0010] According to an embodiment of the present invention, the cold cavity device for the compatible cavity enhanced optical lattice further includes a thermal insulation support structure, which is disposed between the bottom plate of the vacuum cavity and the lower part of the shell of the cold cavity, for fixing and supporting the cold cavity inside the vacuum cavity.

[0011] According to an embodiment of the present invention, the laser incident window is a double-layer window structure, including an outer window sheet and an inner window sheet, with a vacuum between the outer window sheet and the inner window sheet, so that the outer window sheet acts as a thermal shield for the inner window sheet.

[0012] According to an embodiment of the present invention, the cold cavity device of the cavity-enhanced optical lattice further includes a temperature sensor disposed on the housing of the cold cavity to monitor the temperature of the cold cavity.

[0013] According to another aspect of the present invention, an atomic optical clock is provided, including the above-mentioned cold cavity device for a compatible cavity-enhanced optical lattice. Attached Figure Description

[0014] The objects, features, and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0015] Figure 1 This is a schematic diagram of the cold cavity device for a compatible cavity enhanced optical lattice according to an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of the internal structure of the vacuum cavity and cold cavity in an embodiment of the present invention.

[0017] Figure 3This is a schematic diagram of the cavity reinforcement structure according to an embodiment of the present invention.

[0018] Figure 4 This is a three-dimensional structural diagram of the first laparoscope section according to an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures

[0020] 1. Cold cavity;

[0021] 2. Vacuum chamber;

[0022] 3. Atomic source;

[0023] 4. Cold source;

[0024] 5. Cavity reinforcement structure;

[0025] 6. Thermal insulation support structure;

[0026] 7. Temperature sensor;

[0027] 10. Shell;

[0028] 11. Laser incident window;

[0029] 12. First extension;

[0030] 13. Second extension;

[0031] 21. First shell window;

[0032] 22. Second shell window;

[0033] 23. Vacuum View Window;

[0034] 24. Base plate;

[0035] 41. Cold chain;

[0036] 51. First laparoscope section;

[0037] 52. Second laparoscope section;

[0038] 510. First laparoscope;

[0039] 511. First adapter ring;

[0040] 512. Copper ring;

[0041] 513. Piezoelectric ceramic ring;

[0042] 520. Second laparoscope;

[0043] 521. Second adapter ring. Detailed Implementation

[0044] This invention provides a cold cavity device and an atomic optical clock that are compatible with cavity-enhanced optical lattices, which comprehensively improve the clock transition frequency and achieve a more accurate optical lattice clock.

[0045] Factors such as electric fields, cold collisions between atoms within the cold cavity, and background gas collisions can cause shifts in the clock transition frequency of optical clocks. Among the many frequency shift factors currently limiting the accuracy of neutral cold atom optical clocks, blackbody radiation frequency shift, lattice light Stark frequency shift, and density frequency shift are the most critical. Reducing the temperature of the thermal environment in which the atoms reside is the main way to suppress the uncertainty of blackbody radiation frequency shift. Optical lattice clocks bind atoms in optical lattice potential wells, which can eliminate the frequency shift caused by atomic thermal motion, but the lattice photoelectric field simultaneously introduces lattice light Stark frequency shift. When the lattice light operates at the magic frequency, this frequency shift has a net effect of zero on the clock transition frequency. Therefore, to suppress the lattice light Stark frequency shift, the lattice light needs to be precisely locked at the magic frequency, which places extremely high demands on the frequency stability of the laser. To suppress the density frequency shift caused by interactions between atoms within the same lattice, it is usually necessary to increase the beam waist of the lattice light to reduce the atomic number density. However, at the same lattice potential well depth, a larger beam waist means higher laser power, which poses a greater challenge to the output optical power of the laser. Currently, the mainstream method to suppress the two frequency shifts mentioned above is to use a Fabry-Perot cavity enhancement structure. A Fabry-Perot cavity consists of two high-reflectivity cavity mirrors. The incident laser is reflected multiple times between the two cavity mirrors, which significantly enhances the laser power density within the cavity, thereby reducing the requirement for incident light power. At the same time, the Fabry-Perot cavity only allows lasers of specific frequencies to pass through, which has excellent filtering and frequency selection effects, helping to improve the frequency stability of lattice light. Blackbody radiation frequency shift is currently the primary factor restricting the improvement of optical clock accuracy. Room temperature methods are nearing their limits, and a cold cavity solution must be adopted. To suppress the Stark frequency shift and density frequency shift of lattice light, it is necessary to introduce a Fabry-Perot cavity enhancement structure for lattice light with a large beam waist. Therefore, this invention proposes a cold cavity device and an atomic optical clock that is compatible with cavity-enhanced optical lattice.

[0046] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0047] In this embodiment of the invention, a cold cavity device for cavity-enhanced optical lattices is provided, combined with... Figure 1 , Figure 2 and Figure 3 As shown, the cold cavity device of this compatible cavity-enhanced optical lattice mainly includes a cold cavity 1, a vacuum cavity 2, an atomic source 3, a cold source 4, and a cavity enhancement structure 5. Wherein:

[0048] The cold cavity 1 is located inside the vacuum cavity 2. The cold cavity 1 includes a shell 10 and a receiving space inside the shell. The shell 10 of the cold cavity is provided with multiple laser incident windows 11. The receiving space inside the cold cavity is used to accommodate atoms input by the atomic source 3.

[0049] Cold source 4 is used to maintain the temperature of the cold cavity at the target temperature, for example, the target temperature is 77K (Kelvin).

[0050] The cavity enhancement structure 5 includes two cavities: a first cavity mirror 51 and a second cavity mirror 52. The first cavity mirror 51 includes a first cavity mirror 510 and a first adapter ring 511. The second cavity mirror 52 includes a second cavity mirror 520 and a second adapter ring 521. The first cavity mirror 51 is fixed to the position opposite to the first housing window 21 of the vacuum cavity via the first adapter ring 511. The second cavity mirror 52 is fixed to the position opposite to the second housing window 22 of the vacuum cavity via the second adapter ring 521. The first housing window 21 and the second housing window 22 are positioned opposite each other.

[0051] The housing 10 of the cold cavity 1 is further provided with a hollow tubular first extension 12 and a second extension 13. The first extension 12 faces the first cavity mirror 51, and the second extension 13 faces the second cavity mirror 52. This allows the lattice light incident into the cold cavity through the cavity enhancement structure 5 to be reflected and enhanced between the first cavity mirror 510 and the second cavity mirror 520, and to be continuously locked at the magic frequency to obtain a stable optical lattice. It should be noted that the lattice light can be incident into the cold cavity either through the first cavity mirror 510 or the second cavity mirror 520 of the cavity enhancement structure 5.

[0052] It should be noted that, in order to facilitate the demonstration of the structure of cold cavity 1, Figure 1 Only the base plate 24 of the vacuum chamber 2 is shown; the other shell structures of the vacuum chamber 2 on the base plate 24 are not shown. Figure 2 The internal structure and assembly relationship of vacuum chamber 2 and cold chamber 1 are shown in the figure.

[0053] Since the cold cavity 1 is located inside the vacuum cavity 2, the housing of the vacuum cavity 2 is provided with vacuum windows 23 at positions corresponding to the laser incident windows 11 on the housing 10 of the cold cavity 1, for different lasers (e.g., lasers of different wavelengths or different incident angles) to be incident.

[0054] According to embodiments of the present invention, in combination Figure 3 and Figure 4As shown, the first cavity mirror section 51 also includes a copper ring 512 and a piezoelectric ceramic ring 513 disposed between the first cavity mirror 510 and the first adapter ring 511, such that the first cavity mirror 510, copper ring 512, piezoelectric ceramic ring 513 and first adapter ring 511 are sequentially fitted together; the extension and retraction of the piezoelectric ceramic ring 513 is adjusted by adjusting the voltage acting on the piezoelectric ceramic ring 513 to keep the distance between the first cavity mirror 510 and the second cavity mirror 520 stable. More specifically, the first cavity mirror 510 is glued to the copper ring 512 with vacuum epoxy resin, the copper ring 512 is then glued to the piezoelectric ceramic ring 513, and the piezoelectric ceramic ring 513 is glued to the first adapter ring 511. The first adapter ring 511 is finally fixed to the vacuum side of the first housing window of the vacuum chamber. To prevent the charge accumulated on the piezoelectric ceramic ring 513 from being conducted to the first cavity mirror 510 and causing a DC Stark frequency shift, the copper ring 512 is connected to the shell of the vacuum cavity via a wire, allowing the charge to be conducted away in a timely manner. By adjusting the voltage to change the expansion and contraction of the piezoelectric ceramic ring 513, the changes in the distance between the two cavity mirrors caused by noise such as temperature fluctuations and mechanical vibrations can be compensated, keeping the distance between the two cavity mirrors constant, thereby continuously locking the frequency of the lattice light in the cavity at the magic frequency.

[0055] According to an embodiment of the present invention, the internal mirror surfaces of the first cavity mirror 510 and the second cavity mirror 520 are both coated with a reflective film, which has a reflectivity of not less than 99.9% for lattice light wavelength; the inner wall surface of the shell of the cold cavity is coated with a black coating to absorb the heat radiation entering the cold cavity from the outside, while reducing the reflectivity of heat radiation inside the cold cavity and reducing stray heat radiation reflected to the atomic position.

[0056] The relative stability of the lattice light frequency is proportional to the relative stability of the spacing between the first cavity mirror 510 and the second cavity mirror 520. Therefore, to ensure the frequency stability of the lattice light, the spacing between the first cavity mirror 510 and the second cavity mirror 520 must be kept constant. By controlling the expansion and contraction of the piezoelectric ceramic ring through feedback, the spacing between the first cavity mirror 510 and the second cavity mirror 520 can be precisely adjusted and locked, thereby locking the frequency of the lattice light in the cold cavity at the magic frequency. In addition, both the first cavity mirror 510 and the second cavity mirror 520 are placed in a vacuum environment without any window between them, so the loss in the cold cavity is negligible, and the power density of the lattice light in the cold cavity can be amplified hundreds of times relative to the incident lattice light. Meanwhile, both the first and second cavity mirrors are mounted on the housing of the vacuum cavity, not on the housing of the cold cavity, and the first extension 12 and the first cavity mirror 51 do not contact each other, as do the second extension 13 and the second cavity mirror 52. This is because the cold cavity 1 will deform after cooling, and if they contact each other, it will be detrimental to maintaining the stability of the distance between the first cavity mirror 510 and the second cavity mirror 520.

[0057] According to an embodiment of the present invention, the solid angle of external thermal radiation entering the cold cavity through the first extension 12 and the second extension 13 is compressed by configuring the ratio of the length to the inner diameter of the first extension 12 and the second extension 13.

[0058] According to an embodiment of the present invention, the copper ring 512 is electrically connected to the housing of the vacuum cavity via a wire, which is used to conduct away the static charge accumulated on or inside the piezoelectric ceramic ring 513, so as to prevent the charge from being conducted to the first cavity mirror 510 and generating DC Stark frequency shift.

[0059] According to an embodiment of the present invention, the cold source 4 is connected to the shell 10 of the cold cavity 1 through a flexible cold chain 41, so as to suppress the transmission of mechanical vibration of the cold source 4 to the cold cavity 1 while conducting cold energy.

[0060] According to an embodiment of the present invention, the cold cavity device for the compatible cavity enhanced optical lattice further includes a thermal insulation support structure 6, which is disposed between the bottom plate 24 of the vacuum cavity and the lower part of the shell of the cold cavity, for fixing and supporting the cold cavity inside the vacuum cavity. The thermal insulation support structure 6 is preferably made of a material with low thermal conductivity to reduce the thermal conduction between the vacuum cavity 2 and the cold cavity 1.

[0061] According to an embodiment of the present invention, the laser incident window is a double-layer window structure, including an outer window sheet and an inner window sheet, with a vacuum between the outer window sheet and the inner window sheet, so that the outer window sheet acts as a thermal shield for the inner window sheet.

[0062] According to embodiments of this disclosure, the cold cavity device for a cavity-enhanced optical lattice further includes a temperature sensor 7, such as... Figure 2 As shown, temperature sensor 7 is mounted on the housing 10 of the cold cavity to monitor the temperature of the cold cavity. Temperature sensor 7 can be a platinum resistance thermometer, a thermistor, a thermocouple, etc. To ensure that the temperature measured by the temperature probe is consistent with the cavity temperature, the probe of temperature sensor 7 is encapsulated in an oxygen-free copper housing with a vacuum low outgassing rate and electrical insulation epoxy resin. After encapsulation, indium foil is attached to the bottom surface of the temperature probe and it is fixed to the surface of the cavity by screws.

[0063] In another aspect, the present invention provides an atomic optical clock, including the aforementioned cold cavity device of a cavity-enhanced optical lattice. By employing the cold cavity device of the cavity-enhanced optical lattice proposed in this invention, the accuracy of the atomic optical clock can be improved, with an uncertainty reaching 10-1. -19 At or below the level of [the target].

[0064] The cold cavity 1 surrounds the atoms of the incident atomic beam, placing them in a low-temperature thermal radiation environment. At the center of the cold cavity, the atoms are trapped in a magneto-optical trap formed by multiple pairs of lasers (e.g., three pairs) and a gradient magnetic field. To reduce temperature non-uniformity in different parts of the cold cavity 1, materials with good thermal conductivity, such as oxygen-free copper, can be used. The inner wall of the cold cavity 1 is coated with a high-emissivity black paint to absorb the high-temperature thermal radiation incident into the cold cavity, reducing the proportion of thermal radiation reflected to the atoms. The cold source can be, for example, liquid nitrogen, cryogenic nitrogen, liquid helium, cryogenic helium, or a refrigerator. The vacuum cavity 2 maintains an ultra-high vacuum to prevent frost formation in the cold cavity 1 due to low temperature. Multiple vacuum windows 23 are provided on the surface of the vacuum cavity 2 to allow the incident laser to pass through and manipulate the atoms. The thermal insulation support structure 6 combines high strength and low thermal conductivity, and can be made of thin-walled metal tubes or plastics to suppress heat transfer between the vacuum cavity and the cold cavity. The cold chain 41 employs a flexible structure to effectively suppress the transmission of cold source vibrations to the cold cavity. The laser incident window on the shell 10 of the cold cavity is a double-layered window. Considering that the absorption rate of high-temperature (e.g., room temperature) thermal radiation by a window made of glass (approximately 0.9) is much higher than that of the large surface area of ​​the cold cavity shell made of metal (approximately 0.1), and that the thermal conductivity of the laser incident window material (approximately 1 W / m / K for glass) is much lower than that of the cold cavity material (approximately 400 W / m / K for oxygen-free copper), if only a single-layered window is used, the temperature of the laser incident window will be significantly higher than the shell and internal temperature of the cold cavity, thus disrupting the uniformity of the atomic thermal environment. The double-layered window structure uses the outer window as a thermal shield for the inner window, ensuring that the temperature of the inner window directly facing the atoms remains consistent with the temperature of the cold cavity, thereby reducing temperature non-uniformity.

[0065] During operation, the atomic beam emitted from the atomic source enters and is captured in the central region of the cold cavity. Subsequently, various lasers manipulate the atoms and probe for clock signals. The cryogenic environment provided by the cold cavity significantly suppresses the blackbody radiation frequency shift and its uncertainty. However, ambient room temperature radiation can still enter the cold cavity through openings such as the atomic entrance and the lattice light incident channel. The solid angle at which ambient room temperature radiation enters is proportional to... ,in It is the opening area. This refers to the distance from the opening to the atom. To reduce room-temperature radiation introduced by these openings, each entrance reduces its solid angle by extending the channel length. This allows for a larger opening diameter while achieving a smaller solid angle, thus accommodating lattice beams with large beam waists. Several temperature probes encapsulated in copper shells can be installed throughout the cavity to measure the temperature at various points within the cold cavity and calculate the temperature at the location of the atoms inside. The worse the thermal uniformity of the cold cavity, the greater the uncertainty in the calculated atomic position temperature. The cold cavity is fixed within the vacuum cavity by supports with low thermal conductivity, high structural strength, and low outgassing rate (such as thin-walled stainless steel columns or polyetheretherketone plastic) to suppress the thermal load introduced by heat conduction. Furthermore, the increased power density within the cold cavity allows for a suitable increase in the lattice beam waist, effectively reducing the atomic density and thus decreasing the density frequency shift caused by interatomic interactions. Simultaneously, the Fabry-Perot cavity also has spectral filtering capabilities, which can suppress frequency noise in the lattice beam to some extent.

[0066] The cold cavity device and atomic optical clock of the compatible cavity enhanced optical lattice of the present invention can reduce the cold cavity temperature to a low level, which can greatly reduce the uncertainty of blackbody radiation frequency shift compared with room temperature cavity schemes. Moreover, during operation, neither moving atoms nor moving parts such as motors are required to rotate the cold cavity, thereby avoiding the introduction of additional clock signal probing dead time and eliminating vibrations that affect the stability of the optical path.

[0067] While maintaining a low-temperature environment, the cold cavity device of the compatible cavity-enhanced optical lattice of this invention can effectively reduce the solid angle of room temperature radiation entering the cold cavity by extending the pipe length of the atomic inlet and other optical openings, thus still retaining a large light-transmitting aperture. This allows lattice light with a large beam waist radius to pass smoothly and be compatible with the cavity enhancement structure. As a result, the atomic number density within the optical lattice is reduced, the frequency stability of the lattice light is improved, and the demand for incident laser power is correspondingly reduced, thereby reducing the Stark shift and density shift of the lattice light. Furthermore, the cold cavity device of the compatible cavity-enhanced optical lattice of this invention places the optical lattice cavity enhancement structure within a vacuum cavity, with no other optical windows between the two cavity mirrors, effectively reducing the intracavity loss of the Fabry-Perot cavity and significantly increasing the amplification factor of the intracavity laser power. Additionally, the absence of optical windows also avoids interference from birefringence and etalon effects.

[0068] The cold cavity device of the compatible cavity enhanced optical lattice of the present invention has a large surface area and can be used as a cryogenic pump to provide additional gas pumping speed, thereby improving the vacuum degree inside the cavity and reducing the background gas collision frequency shift.

[0069] The embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. It should be noted that implementations not illustrated or described in the drawings or the main text of the specification are forms known to those skilled in the art and have not been described in detail. It should be understood that the above are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A cold cavity device for cavity-enhanced optical lattices, characterized in that, include: A cold cavity is located inside a vacuum cavity. The cold cavity includes a shell and a receiving space inside the shell. The shell of the cold cavity is provided with multiple laser incident windows, and the receiving space inside the cold cavity is used to accommodate atoms input by an atomic source. A cold source is used to maintain the temperature of the cold cavity at the target temperature. The cavity enhancement structure includes a first cavity mirror section and a second cavity mirror section. The first cavity mirror section includes a first cavity mirror and a first adapter ring. The second cavity mirror section includes a second cavity mirror and a second adapter ring. The first cavity mirror section is fixed to the position opposite to the first housing window of the vacuum cavity via the first adapter ring. The second cavity mirror section is fixed to the position opposite to the second housing window of the vacuum cavity via the second adapter ring. The first housing window and the second housing window are positioned opposite each other. The shell of the cold cavity is also provided with a hollow tubular first extension and a second extension. The first extension faces the first cavity mirror and the second extension faces the second cavity mirror, so that the lattice light incident into the cold cavity through the cavity enhancement structure is reflected and enhanced between the first cavity mirror and the second cavity mirror and continuously locked at the magic frequency to obtain a stable optical lattice.

2. The cold cavity device for compatibility-enhanced optical lattices according to claim 1, characterized in that, The first endoscope section further includes a copper ring and a piezoelectric ceramic ring disposed between the first endoscope and the first adapter ring, such that the first endoscope, the copper ring, the piezoelectric ceramic ring and the first adapter ring are sequentially fitted together; the extension and retraction of the piezoelectric ceramic ring are adjusted by adjusting the voltage applied to the piezoelectric ceramic ring, so that the distance between the first endoscope and the second endoscope remains stable.

3. The cold cavity device for compatibility-enhanced optical lattices according to claim 1, characterized in that, The internal mirrors of the first and second cavity mirrors are coated with reflective films, and the reflective films have a reflectivity of not less than 99.9% for lattice light wavelengths. The inner wall surface of the shell of the cold cavity is coated with a black coating to absorb external heat radiation entering the cold cavity, while reducing the reflectivity of heat radiation inside the cold cavity and reducing stray heat radiation reflected to the atomic positions.

4. The cold cavity device for compatibility-enhanced optical lattices according to claim 1, characterized in that, The ratio of the length to the inner diameter of the first extension and the second extension is configured to compress the solid angle of external thermal radiation entering the cold cavity through the first extension and the second extension.

5. The cold cavity device for compatibility-enhanced optical lattices according to claim 2, characterized in that, The copper ring is electrically connected to the housing of the vacuum cavity via a wire, which is used to conduct away the static charge accumulated on the surface or inside of the piezoelectric ceramic ring, so as to prevent the charge from being conducted to the first cavity mirror and causing DC Stark frequency shift.

6. The cold cavity device for compatibility-enhanced optical lattices according to claim 1, characterized in that, The cold source is connected to the cold cavity via a flexible cold chain to suppress the transmission of mechanical vibrations from the cold source to the cold cavity while conducting cold energy.

7. The cold cavity device for compatibility-enhanced optical lattices according to claim 1, characterized in that, It also includes a heat-insulating support structure, which is disposed between the bottom plate of the vacuum chamber and the lower part of the shell of the cold chamber, for fixing and supporting the cold chamber inside the vacuum chamber.

8. The cold cavity device for compatibility-enhanced optical lattices according to claim 1, characterized in that, The laser incident window has a double-layer window structure, including an outer window sheet and an inner window sheet. The space between the outer window sheet and the inner window sheet is a vacuum, so that the outer window sheet acts as a thermal shield for the inner window sheet.

9. The cold cavity device for compatibility-enhanced optical lattices according to claim 1, characterized in that, It also includes a temperature sensor, which is disposed on the housing of the cold cavity to monitor the temperature of the cold cavity.

10. An atomic optical clock, characterized in that, The cold cavity device comprising the compatible cavity enhanced optical lattice as described in any one of claims 1-9.

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