A multifunctional microwave cavity for cold atomic clocks

Abstract

The present invention relates to the technical field of cold atomic clocks and provides a multifunctional microwave cavity for a cold atomic clock, comprising a cavity body and upper and lower end caps disposed at the upper and lower ends of the cavity body, respectively. The multifunctional microwave cavity for a cold atomic clock provided by the present invention can perform operations such as laser cooling, state selection, and detection on atoms located at the center of the cavity body, thereby expanding the microwave cavity from a single microwave excitation function to a multifunctional microwave cavity capable of satisfying all cold atomic clock operations. This improves microwave cavity utilization, significantly reduces the overall volume and weight of the cold atomic clock, and transforms the atomic action region of the cold atomic clock from a separate type to an integrated type, thereby reducing system dead time, significantly minimizing the Dick effect, and simultaneously reducing atomic loss and quantum projection noise.

Description

Technical Field

[0001] The present invention relates to the technical field of cold atomic clocks, and in particular to a multifunctional microwave cavity for cold atomic clocks. Background Art

[0002] Since the definition of the second was revised in 1967, researchers at home and abroad have developed a variety of time and frequency generation devices to achieve highly accurate and stable time and frequency standards. The development of modern science and technology is increasingly dependent on highly accurate and stable time, especially in fields such as navigation and positioning, power generation, communications, and measurement and control, with applications expanding rapidly.

[0003] Atomic clocks are primarily categorized by their working material into thermal and cold atomic clocks. Common thermal atomic clocks include spectrum lamp rubidium bulb clocks, CPT rubidium clocks, cesium beam clocks, and hydrogen clocks, while common cold atomic clocks include cesium (rubidium) fountain clocks, cesium (rubidium) integrating sphere clocks, and cold atomic optical clocks. After years of development, the R&D and production processes of these thermal atomic clocks have become highly mature. Their specifications vary depending on the application scenario. Cesium and hydrogen clocks, used as high-precision frequency standards in large-scale timekeeping and metrology institutions, are nearing their limits and cannot fully meet future application demands for high-precision time and frequency benchmarks. Researchers are beginning to explore the potential of cold atomic clocks, hoping to improve their reliability and engineering capabilities, maintain high precision while reducing their size, and realize the next generation of high-performance atomic clocks.

[0004] The microwave cavity is a crucial component of a cold atomic clock. It's the site where cold atoms interact with microwaves, enabling external frequency sources to probe atomic energy levels. Its performance significantly impacts the overall performance of the cold atomic clock. The microwave cavity in a fountain clock is often used as a standalone microwave device, while atomic cooling, state selection, and detection are performed elsewhere in the system. This leads to the following major issues:

[0005] 1. The system is too large and heavy, which is not conducive to improving the integration and reliability of the cold atomic clock. Compared with other atomic clocks, it has a significant disadvantage in portability.

[0006] 2. The separated atomic action area increases the proportion of system dead time and reduces the atomic excitation duty cycle. The resulting Dick effect frequency shift will have a significant adverse impact on the stability of the cold atomic clock.

[0007] 3. The separated atomic action area causes greater atomic loss before excitation, resulting in greater quantum projection noise. Summary of the Invention

[0008] The purpose of the present invention is to provide a multifunctional microwave cavity for a cold atomic clock, which can be used for microwave excitation of cold atoms and can also meet the needs of laser cooling, state selection and detection of atoms, thereby reducing the volume and weight of the cold atomic clock system, improving portability and reliability, while reducing the Dick effect and quantum projection noise, and improving system stability.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A multifunctional microwave cavity for a cold atomic clock comprises a cavity body and upper and lower end covers respectively disposed at the upper and lower ends of the cavity body, the lower end cover being provided with an end cover cutoff waveguide communicating with the interior of the cavity body, and the upper end cover being provided with a first laser through hole corresponding to the end cover cutoff waveguide, the first laser through hole being communicated with the interior of the cavity body;

[0011] The circumferential side walls of the cavity body are respectively provided with a second laser through hole, a third laser through hole, a fourth laser through hole, and a fifth laser through hole that are in communication with the interior of the cavity body. The second laser through hole, the third laser through hole, the fourth laser through hole, and the fifth laser through hole are distributed in a 90° circular array. The first laser through hole, the second laser through hole, the third laser through hole, the fourth laser through hole, and the fifth laser through hole are all provided with an optical mechanical accessory A, which is used to realize the reflection of the cooling laser.

[0012] Among them, the cooling laser is incident upward into the interior of the cavity body through the end cover cutoff waveguide, and is reflected by the optical-mechanical accessory A at the first laser through hole, the second laser through hole, the third laser through hole, the fourth laser through hole and the fifth laser through hole in sequence, forming three pairs of opposing and orthogonal lasers in the inner center of the cavity body.

[0013] In some possible embodiments, the circumferential side wall of the cavity body is further provided with a first state selection detection hole, a second state selection detection hole, and at least one fluorescence detection hole that are connected to the interior of the cavity body. The first state selection detection hole and the second state selection detection hole are symmetrically distributed at 180°. An optical-mechanical accessory B is provided at each of the first state selection detection hole and the second state selection detection hole. The optical-mechanical accessory B is used to reflect the state selection laser or the detection laser. The optical-mechanical accessory B at the first state selection detection hole has a hole for the state selection laser or the detection laser to enter.

[0014] The fluorescence detection hole is located on the perpendicular midline of the line connecting the first state selection detection hole and the second state selection detection hole, and a fluorescence collection device is provided at the fluorescence detection hole;

[0015] Among them, the state selection laser or detection laser enters the interior of the cavity body through the optical-mechanical accessory B at the first state selection detection hole. The state selection laser or detection laser entering the cavity body reaches the optical-mechanical accessory B at the second state selection detection hole through the internal center of the cavity body and is reflected to form a standing wave.

[0016] In some possible embodiments, the optical-mechanical accessory A and the optical-mechanical accessory B both include a housing and a reflector. One side of the housing is an open structure, and the reflector is built into the housing.

[0017] In some possible embodiments, a wave plate or a wave plate group is further provided in the optical-mechanical accessory A at the fifth laser through hole, and the wave plate or the wave plate group is located upstream of the reflective mirror inside the optical-mechanical accessory A.

[0018] In some possible embodiments, the fluorescence collection device includes a fluorescence collection lens and a phototube.

[0019] In some possible embodiments, the cavity body, the upper end cover and the lower end cover are made of non-magnetic materials.

[0020] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0021] The multifunctional microwave cavity for a cold atomic clock provided by the present invention can realize operations such as laser cooling, state selection and detection of atoms located in the center of the cavity body, so that the microwave cavity is expanded from a single microwave excitation function to a multifunctional microwave cavity that meets all operations of the cold atomic clock, thereby improving the utilization rate of the microwave cavity, greatly reducing the overall volume and weight of the cold atomic clock, and changing the atomic action area of ​​the cold atomic clock from a separate type to an integrated type, reducing the dead time of the system, greatly reducing the Dick effect, and at the same time reducing the loss of atoms and the quantum projection noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic structural diagram of a multifunctional microwave cavity provided in an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of the working principle of the multifunctional microwave cavity provided by an embodiment of the present invention for achieving atomic laser cooling;

[0024] Figure 3 A schematic diagram of the working principle of the multifunctional microwave cavity provided in an embodiment of the present invention for realizing atomic state selection or detection.

[0025] Icons: 10-cavity body, 20-upper end cover, 30-lower end cover, 40-end cover cutoff waveguide, 50-optical mechanical accessory A, 60-optical mechanical accessory B, 70-fluorescence collection device, a-first laser through hole, b-second laser through hole, c-third laser through hole, d-fourth laser through hole, e-fifth laser through hole, f-first state selection detection hole, g-second state selection detection hole, h-fluorescence detection hole. Implementation Method Example

[0026] Please refer to Figures 1 to 3 This embodiment provides a multifunctional microwave cavity for a cold atomic clock, which can realize laser cooling, state selection and detection of atoms through the same microwave cavity, thereby expanding the microwave cavity from a single microwave excitation function to a multifunctional microwave cavity that can meet all operations of the cold atomic clock. Figure 1 As shown in the content, the multifunctional microwave cavity includes a cavity body 10, an upper end cover 20 and a lower end cover 30, wherein the upper end cover 20 and the lower end cover 30 are respectively arranged at the upper and lower ends of the cavity body 10, so that the interior of the cavity body 10 constitutes a relatively closed cavity. It can be understood that the inner surface of the cavity body 10 can be cylindrical or other shapes. In actual implementation, it is only necessary to change the three-dimensional dimensions of the inner surface of the cavity body 10 to change the resonant frequency of the microwave cavity to match the energy level transition frequency of the working atom.

[0027] At the same time, the cavity body 10, the upper end cover 20 and the lower end cover 30 in this embodiment can all be made of non-magnetic materials, such as oxygen-free copper or aluminum alloy, and different inner surface treatment methods can be used to treat the inner surfaces of the cavity body 10, the upper end cover 20 and the lower end cover 30 according to different microwave cavity Q value requirements, such as polishing or plating non-magnetic metal film, so as to meet the use of cold atomic clocks with different index requirements.

[0028] In this embodiment, in order to realize laser cooling of atoms, continue to refer to Figure 1 The lower end cap 30 is provided with an end cap cutoff waveguide 40 communicating with the interior of the cavity body 10. The end cap cutoff waveguide 40 is used for the cooling laser for laser cooling of atoms to be incident into the interior of the cavity body 10. At this time, combined with Figure 2 As shown, the upper end cover 20 is provided with a first laser through hole a corresponding to the end cover cutoff waveguide 40 , that is, the first laser through hole a is opposite to the end cover cutoff waveguide 40 , and the first laser through hole a is connected to the interior of the cavity body 10 .

[0029] Meanwhile, continue to refer to Figure 2The circumferential side walls of the cavity body 10 are respectively provided with a second laser through hole b, a third laser through hole c, a fourth laser through hole d and a fifth laser through hole e which are connected to the interior of the cavity body 10. The second laser through hole b, the third laser through hole c, the fourth laser through hole d and the fifth laser through hole e are distributed in a 90° circular array. The first laser through hole a, the second laser through hole b, the third laser through hole c, the fourth laser through hole d and the fifth laser through hole e are all provided with an optical-mechanical accessory A50, which is used to realize the reflection of the cooling laser.

[0030] It is understandable that, combined with Figure 1 As shown in the content, the optical-mechanical accessory A50 at the first laser through-hole a in this embodiment is set on the top of the upper end cover 20, while the optical-mechanical accessories A50 at the second laser through-hole b, the third laser through-hole c, the fourth laser through-hole d, and the fifth laser through-hole e are all set on the circumferential outer wall of the cavity body 10. At this time, each optical-mechanical accessory A50 includes a shell and optical elements such as a reflector. One side of the shell of the optical-mechanical accessory A50 is an open structure so that the cooling laser passing through the above-mentioned laser through-holes can enter the interior of the shell of the corresponding optical-mechanical accessory A50, and the reflector is built into the shell to achieve reflection of the cooling laser. At the same time, in actual implementation, the shell of the optical-mechanical accessory A50 at each of the above-mentioned laser through-holes can be integrally processed and formed with the cavity body 10 or the upper end cover 20, or can be manufactured separately as an independent component, which is not specifically limited here.

[0031] Among them, in the laser cooling stage of the atoms in the center of the cavity body 10, the cooling laser is incident upward into the cavity body 10 through the end cover cutoff waveguide 40, and is reflected by the optical-mechanical accessory A50 at the first laser through hole a, the second laser through hole b, the third laser through hole c, the fourth laser through hole d and the fifth laser through hole e in sequence, forming three pairs of opposing and orthogonal cooling lasers in the center of the cavity body 10 to achieve laser cooling of the atoms.

[0032] For example, in this embodiment, the second laser through hole b is opposite to the third laser through hole c, and the fourth laser through hole d is opposite to the fifth laser through hole e. In the laser cooling stage, Figure 2As shown, the cooling laser is incident into the cavity body 10 through the end cover cutoff waveguide 40 and then passes through the center of the cavity body 10 and through the first laser through-hole a. At this time, the cooling laser is reflected by the reflector in the optical-mechanical accessory A50 at the first laser through-hole a and enters the interior of the optical-mechanical accessory A50 at the second laser through-hole b. The cooling laser entering the interior of the optical-mechanical accessory A50 at the second laser through-hole b is reflected by the reflector in the optical-mechanical accessory A50 and then passes through the second laser through-hole b and passes through the center of the cavity body 10 again to pass through the third laser through-hole c. The cooling laser passing through the third laser through-hole c enters the interior of the optical-mechanical accessory A50 at the third laser through-hole c. The cooling laser entering the interior of the optical-mechanical accessory A50 at the third laser through-hole c passes through the optical-mechanical accessory A50 After being reflected by the reflective mirror inside, the cooling laser enters the interior of the optical-mechanical accessory A50 at the fourth laser through-hole d. The cooling laser entering the interior of the optical-mechanical accessory A50 at the fourth laser through-hole d is reflected by the reflective mirror inside the optical-mechanical accessory A50, passes through the fourth laser through-hole d, and passes through the center of the cavity body 10 again to pass through the fifth laser through-hole e. The cooling laser passing through the fifth laser through-hole e is reflected by the reflective mirror inside the optical-mechanical accessory A50 at the fifth laser through-hole e and returns to the original path. At this time, three pairs of opposing and orthogonal cooling lasers are formed between the end cover cutoff waveguide 40 and the first laser through-hole a, between the second laser through-hole b and the third laser through-hole c, and between the fourth laser through-hole d and the fifth laser through-hole e, so as to realize laser cooling of the atoms at the center of the cavity body 10.

[0033] It should be noted that in order to enable the cooling laser reflected by the reflector in the optical-mechanical accessory A50 at the first laser through-hole a to smoothly enter the interior of the optical-mechanical accessory A50 at the second laser through-hole b, a hole for the cooling laser to pass through can be opened on the shell of the optical-mechanical accessory A50 at the first laser through-hole a and the shell of the optical-mechanical accessory A50 at the second laser through-hole b (not shown in the figure). Correspondingly, in order to enable the cooling laser reflected by the reflector in the optical-mechanical accessory A50 at the third laser through-hole c to smoothly enter the interior of the optical-mechanical accessory A50 at the fourth laser through-hole d, a hole for the cooling laser to pass through can be opened on the shell of the optical-mechanical accessory A50 at the third laser through-hole c and the shell of the optical-mechanical accessory A50 at the fourth laser through-hole d (not shown in the figure).

[0034] In addition, in actual implementation, combined with Figure 2 As shown in the content, a wave plate or a wave plate group can be set inside the shell of the optical-mechanical accessory A50 at the fifth laser through hole e, and the wave plate or the wave plate group is located upstream of the reflector inside the optical-mechanical accessory A50. That is to say, when the cooling laser passing through the fifth laser through hole e enters the optical-mechanical accessory A50 at the fifth laser through hole e, it will first pass through the wave plate or the wave plate group and then reach the reflector inside the optical-mechanical accessory A50, so as to perform polarization control on the cooling laser through the wave plate or the wave plate group.

[0035] In this embodiment, in order to realize the state selection or detection of atoms, the Figure 3 As shown in the content, the circumferential side wall of the cavity body 10 is also provided with a first state selection detection hole f, a second state selection detection hole g and at least one fluorescence detection hole h which are connected to the interior of the cavity body 10. The first state selection detection hole f and the second state selection detection hole g are symmetrically distributed at 180°. The first state selection detection hole f and the second state selection detection hole g are both provided with an optical-mechanical accessory B60, which is used to realize the reflection of the state selection laser or the detection laser, and the optical-mechanical accessory B60 at the first state selection detection hole f has a hole for the state selection laser or the detection laser to enter.

[0036] It can be understood that the optical-mechanical accessories B60 at the first state selection detection hole f and the second state selection detection hole g in this embodiment are both arranged on the circumferential outer wall of the cavity body 10. At this time, each optical-mechanical accessory B60 includes a shell and optical elements such as a reflector. One side of the shell of the optical-mechanical accessory B60 is an open structure so that the laser passing through the above-mentioned state selection detection holes can enter the interior of the shell of the corresponding optical-mechanical accessory B60, and the reflector is built into the shell to realize the reflection of the state selection laser or the detection laser. At the same time, in order to enable the state selection laser or the detection laser to smoothly enter the interior of the cavity body 10 during the state selection or detection stage, the shell of the optical-mechanical accessory B60 of the first state selection detection hole f is also provided with a hole for the state selection laser or the detection laser to pass through (not shown in the figure). In addition, in actual implementation, the shell of the optical-mechanical accessory B60 at each of the above-mentioned state selection detection holes can be integrally processed and formed with the cavity body 10, or can be manufactured separately as an independent component, which is not specifically limited here.

[0037] Continue to refer to Figure 3 The fluorescence detection hole h is located on the perpendicular bisector of the line connecting the first state selection detection hole f and the second state selection detection hole g. A fluorescence collecting device 70 is provided at the fluorescence detection hole h. The fluorescence collecting device 70 may include but is not limited to components such as a fluorescence collecting lens and a photoelectric tube, and the fluorescence collecting lens, the photoelectric tube and other components are encapsulated in a shell provided on the circumferential outer wall of the cavity body 10, so as to detect the fluorescence intensity of the central atomic group inside the cavity body 10 through the fluorescence collecting device 70.

[0038] It is understandable that, combined with Figure 3 As shown in the content, the first state selection detection hole f in this embodiment is opened between the third laser through hole c and the fourth laser through hole d, the second state selection detection hole g is opened between the second laser through hole b and the fifth laser through hole e and is opposite to the first state selection detection hole f, and the fluorescence detection hole h is opened between the second laser through hole b and the fourth laser through hole d, so that the overall structural layout of the microwave cavity is more reasonable.

[0039] Among them, in the selection or detection stage, the selection laser or detection laser enters the interior of the cavity body 10 through the optical-mechanical accessory B60 at the first selection detection hole f. The selection laser or detection laser entering the cavity body 10 reaches the optical-mechanical accessory B60 at the second selection detection hole g through the internal center of the cavity body 10 and is reflected to form a standing wave.

[0040] Specifically, in the state selection stage, Figure 3 As shown, the state-selected laser is incident vertically upward through the hole on the shell of the optical-mechanical accessory B60 at the first state-selected detection hole f. At this time, the state-selected laser is reflected by the reflector in the optical-mechanical accessory B60 and then passes through the first state-selected detection hole f to enter the interior of the cavity body 10. The state-selected laser entering the interior of the cavity body 10 passes through the center of the cavity body 10 and then passes through the second state-selected detection hole g to enter the interior of the optical-mechanical accessory B60 at the second state-selected detection hole g, and is reflected by the reflector in the optical-mechanical accessory B60 at the second state-selected detection hole g and then returns to the original path, so as to realize the formation of a standing wave between the first state-selected detection hole f and the second state-selected detection hole g. Different state-selection methods can be adopted according to different state-selected laser frequencies.

[0041] Accordingly, in the detection phase, if Figure 3 As shown, the detection laser is also incident vertically upward through the hole on the shell of the optical-mechanical accessory B60 at the first selection detection hole f. At this time, the detection laser is reflected by the reflector in the optical-mechanical accessory B60 and then passes through the first selection detection hole f to enter the interior of the cavity body 10. The detection laser entering the cavity body 10 passes through the center of the cavity body 10 and then passes through the second selection detection hole g to enter the interior of the optical-mechanical accessory B60 at the second selection detection hole g. It is reflected by the reflector in the optical-mechanical accessory B60 at the second selection detection hole g and then returns to the original path to form a standing wave between the first selection detection hole f and the second selection detection hole g. At the same time, the fluorescence collection device 70 at the fluorescence detection hole h detects the fluorescence intensity of the central atomic group inside the cavity body 10 to achieve the detection purpose.

[0042] It can be seen that the multifunctional microwave cavity for a cold atomic clock provided in this embodiment improves the structure of the microwave cavity and the methods of atomic laser cooling, state selection, and detection. In actual application, only one beam of cooling laser, state selection laser, or detection laser is required to be incident on the interior of the cavity body 10. Under the action of multiple optical-mechanical accessories A50 or optical-mechanical accessories B60, the cooling laser, state selection laser, or detection laser can be deflected multiple times, changed in polarization, and finally returned to the original path to achieve laser cooling, state selection, and detection operations on the atoms located in the center of the cavity body 10. This expands the microwave cavity from a single microwave excitation function to a multifunctional microwave cavity that meets all operations of the cold atomic clock, improves the utilization rate of the microwave cavity, and significantly reduces the overall volume and weight of the cold atomic clock. The atomic action area of ​​the cold atomic clock is changed from a separate type to an integrated type, thereby reducing the system dead time, greatly reducing the Dick effect, and at the same time reducing the loss of atoms and the quantum projection noise.

[0043] It should be noted that, in actual implementation, the number or position of the optical mechanical accessories A50 or the optical mechanical accessories B60 arranged on the circumferential outer wall of the cavity body 10 can be changed to realize a multifunctional folded optical path microwave cavity that meets different application requirements.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A multifunctional microwave cavity for a cold atomic clock, characterized in that: The cavity body comprises an upper end cap and a lower end cap respectively provided at the upper and lower ends of the cavity body, wherein the lower end cap is provided with an end cap cutoff waveguide communicating with the interior of the cavity body, and the upper end cap is provided with a first laser through hole corresponding to the end cap cutoff waveguide, and the first laser through hole is communicated with the interior of the cavity body; The circumferential side walls of the cavity body are respectively provided with a second laser through hole, a third laser through hole, a fourth laser through hole and a fifth laser through hole that are connected to the interior of the cavity body. The second laser through hole, the third laser through hole, the fourth laser through hole and the fifth laser through hole are distributed in a 90° circular array. The first laser through hole, the second laser through hole, the third laser through hole, the fourth laser through hole and the fifth laser through hole are all provided with an optical-mechanical accessory A. The optical-mechanical accessory A at the first laser through hole is provided on the top of the upper end cover. The optical-mechanical accessories A at the second laser through hole, the third laser through hole, the fourth laser through hole and the fifth laser through hole are provided on the circumferential outer wall of the cavity body. The optical-mechanical accessory A is used to realize the reflection of the cooling laser. The cooling laser is incident upward into the cavity body through the end cap cutoff waveguide, and is reflected by the optical-mechanical attachment A at the first laser through hole, the second laser through hole, the third laser through hole, the fourth laser through hole, and the fifth laser through hole in sequence, forming three pairs of oppositely incident and orthogonal cooling lasers at the center of the cavity body; The circumferential side wall of the cavity body is further provided with a first state selection detection hole, a second state selection detection hole, and at least one fluorescence detection hole that are connected to the interior of the cavity body. The first state selection detection hole and the second state selection detection hole are symmetrically distributed at 180 degrees. An optical mechanical accessory B is provided at both the first state selection detection hole and the second state selection detection hole. The optical mechanical accessories at the first state selection detection hole and the second state selection detection hole are both provided on the circumferential outer wall of the cavity body. The optical mechanical accessory B is used to realize the reflection of the state selection laser or the detection laser. The optical mechanical accessory B at the first state selection detection hole has a hole for the state selection laser or the detection laser to enter. The fluorescence detection hole is located on the perpendicular midline of the line connecting the first state selection detection hole and the second state selection detection hole, and a fluorescence collection device is provided at the fluorescence detection hole; Among them, the state selection laser or detection laser enters the interior of the cavity body through the optical-mechanical accessory B at the first state selection detection hole. The state selection laser or detection laser entering the cavity body reaches the optical-mechanical accessory B at the second state selection detection hole through the internal center of the cavity body and is reflected to form a standing wave.

2. The multifunctional microwave cavity for a cold atomic clock according to claim 1, characterized in that: The optical-mechanical accessory A and the optical-mechanical accessory B both include a shell and a reflector. One side of the shell is an open structure, and the reflector is built into the shell.

3. The multifunctional microwave cavity for a cold atomic clock according to claim 2, characterized in that: A wave plate or a wave plate group is further provided in the optical-mechanical accessory A at the fifth laser through hole, and the wave plate or the wave plate group is located upstream of the reflector inside the optical-mechanical accessory A.

4. The multifunctional microwave cavity for a cold atomic clock according to claim 1, characterized in that: The fluorescence collecting device includes a fluorescence collecting lens and a photoelectric tube.

5. The multifunctional microwave cavity for a cold atomic clock according to claim 1, characterized in that: The cavity body, the upper end cover and the lower end cover are made of non-magnetic materials.

Images