JP2006033373A - Microwave cavity resonance device for atom oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To initiate a stable TE011 resonance mode having a specified frequency in a cavity resonator. <P>SOLUTION: A microwave cavity resonance device for an atom oscillator is equipped with a couple of support members 21 and 22 which are provided nearby both axial ends in a cavity resonator 2 and made of materials with a low dielectric constant supporting a gas cell 4 at the center position in the cavity resonator, a dielectric member 26 with a high dielectric constant which is provided to freely be inserted into and extracted from the cavity resonator, a projection quantity adjusting mechanism 27 which adjusts the quantity of projection of the dielectric member with the high dielectric constant into the cavity resonator from one axial end in the cavity resonator, and a recess 23 which is formed on one axial end wall in the cavity resonator and in which a portion of an antenna 24 is stored having a gap with the side wall. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an atomic oscillator using the light absorption characteristics of an absorption gas such as rubidium or cesium 133, and more particularly to a microwave cavity resonator incorporated in the atomic oscillator.

  A microwave cavity resonator which is a core component of a laser excitation type atomic oscillator is reported in, for example, Patent Document 1. That is, the microwave cavity resonator device reported in Patent Document 1 is configured as shown in the sectional view of FIG. A gas cell 32 in which a cylindrical glass container is filled with rubidium gas is disposed in a cylindrical cavity resonator (cavity) 31. Further, an annular dielectric 33 having a low dielectric loss and a relative dielectric constant larger than air is provided in the cavity resonator 31 to adjust the resonance frequency of the cavity resonator 31. The dielectric 33 is a low dielectric loss object such as Teflon (registered trademark).

  A metal screw portion 34 having a large diameter is screwed into a screw hole formed in one axial end wall 31 a of the cavity resonator 31, and the above-described annular dielectric 33 is fixed to the tip of the screw portion 34. Has been. The screw portion 34 is formed with a through hole 35 for allowing the laser beam 38 to penetrate in the axial direction.

  Further, an antenna 36 for supplying a microwave that generates a resonance mode in the cavity resonator 31 is attached to one axial wall 31 a of the cavity resonator 31. Note that a signal obtained by multiplying an oscillation output from a voltage controlled crystal oscillator (VCO) (not shown) is applied to the antenna 36.

  Then, by changing the screwing amount of the screw portion 34 into the screw hole described above, the dielectric 33 is moved in the direction of the arrow, and the volume of the cavity resonator 31 is changed, which is generated in the cavity resonator 31. The resonance frequency in the resonance mode of the microwave is adjusted to a reference resonance frequency (specified frequency) predetermined for rubidium.

  Laser light 38 emitted from an external laser diode 37 enters the cavity resonator 31 through the through hole 35 of the screw portion 34 and further enters the gas cell 32. The laser beam 38 that has passed through the gas cell 32 is incident on a photocell 39 attached to the other axial wall 31 b of the cavity resonator 31, and is converted into an electrical signal by the photocell 39.

  Further, a magnetic shield coil 40 for generating a static magnetic field is wound around the outer periphery of the cavity resonator 31 in the cavity resonator 31 in which the gas cell 32 is housed.

  In the atomic oscillator, a reference frequency to be output to the outside is created using a microwave input frequency that is a reference resonance frequency (specified frequency) when a resonance mode is generated in the cavity resonator 31. In a state where the resonance mode is generated in the cavity resonator 31, the absorption of light in the absorption characteristic with respect to the light of rubidium accommodated in the gas cell 32 is maximized, so that the laser beam 38 received by the photocell 39. The strength of the is minimized. Accordingly, the occurrence of the resonance mode in the cavity resonator 31 is detected by the intensity of the laser beam 38 being minimized.

Therefore, in the microwave cavity resonator, the oscillation output (oscillation frequency) of the voltage controlled crystal oscillator (VCO) is controlled by the electrical signal output from the photocell 39 so that the incident light quantity of the photocell 39 is reduced. As a result, the oscillation frequency of the voltage controlled crystal oscillator (VCO) is made to coincide with the atomic resonance frequency of rubidium.
Japanese Patent Laid-Open No. 7-264064

  However, the microwave cavity resonator shown in FIG. 10 still has the following problems to be solved.

  In the microwave cavity resonator having such a configuration, when rubidium is employed as the absorption gas, the diameter and axial length of the cylindrical cavity resonator 31 are determined based on the above-described reference that the microwave input frequency output from the antenna 36 is the reference described above. Is set so that a resonance mode is generated in the cavity resonator 31 at the resonance frequency (specified frequency).

  However, in the cavity resonator 31, there are a gas cell 32, a dielectric 33, a screw portion 34, an antenna 36, a photocell 39, and the like. These components affect the frequency when the resonance mode is generated. Therefore, the frequency at the time of the resonant mode generation of the manufactured cavity resonator 31 does not necessarily exactly become the reference resonant frequency (specified frequency) described above.

  Therefore, as a method of adjusting the resonance frequency in the resonance mode of the microwave generated in the cavity resonator 31 to a reference resonance frequency (specified frequency) predetermined for rubidium, Teflon (registered trademark) is provided at the tip. The volume of the cavity resonator 31 is changed by changing the screwing amount with respect to the screw hole of the metal screw portion 34 to which the annular dielectric 33 formed of an object of low dielectric loss or the like is attached. That is, the insertion position of the dielectric 33 changes, but the insertion amount of the cavity resonator 31 of the screw portion 34 is changed.

  As a result, the axial length is adjusted without changing the outer diameter of the cavity resonator 31 to adjust the frequency. Therefore, a mode skip phenomenon or the like occurs outside the line of the mode chart which is a cavity resonator design tool, and the cavity resonator 31 is unstable.

  As a result, the screw portion 34 that supports the dielectric 33 formed of a low dielectric loss object such as Teflon (registered trademark) that protrudes greatly into the cavity resonator 31 is formed of metal. The resonance mode is disturbed, and the Q value as a resonator deteriorates.

  Next, impedance matching between the antenna 36 and the coaxial line (semi-rigid) will be described. Unlike the free space, the cavity resonator 31 is almost completely sealed. In addition, since the microwave resonance point is narrow and the microwave input is almost totally reflected in such a sealed state, the impedance of the antenna 36 and the coaxial line (semi-rigid) has a large induction (inductance) component, and impedance matching is achieved. It is quite difficult to take. In particular, in the microwave cavity resonator shown in FIG. 10, it can be estimated that the ¼ wavelength antenna 36 is disposed in the cavity resonator 31, so that impedance matching is quite difficult. As a result, the microwave level in the cavity resonator 31 becomes unstable.

  The present invention has been made in view of such circumstances, and employs the TE011 resonance mode as the microwave resonance mode, and the frequency of the microwave when the TE011 resonance mode of each constituent member existing in the cavity resonator is generated. It is an object of the present invention to provide a microwave cavity resonator device of an atomic oscillator that can easily generate a stable TE011 resonance mode having a specified frequency in a cavity resonator.

  The present invention provides a cylindrical cavity resonator formed in a metal body, a gas cell accommodated in the cavity resonator and encapsulating an absorption gas and a buffer gas, and a TE011 resonance mode in the cavity resonator. The present invention is applied to a microwave cavity resonance device of an atomic oscillator having an antenna for supplying a microwave and a light receiver that receives light incident from the outside and transmitted through a gas cell.

  In order to solve the above problem, in the microwave resonator device of the atomic oscillator of the present invention, the gas cell is provided in the vicinity of both ends in the axial direction in the cylindrical cavity resonator, and the gas cell is arranged at the center position in the cavity resonator. A pair of support members formed of a low dielectric constant material to be supported on, a high dielectric constant dielectric member detachably provided in the cavity resonator, and a microwave frequency when the TE011 resonance mode is generated A protrusion amount adjusting mechanism for adjusting a protrusion amount of the dielectric member having a high dielectric constant from the one end surface in the axial direction in the cavity resonator to the specified frequency, and an axial direction in the cavity resonator And a recess for storing a part of the antenna with a gap with respect to the side wall.

  In the microwave cavity resonance device of the atomic oscillator configured as described above, the TE011 resonance mode shown in FIG. 5B is adopted as the microwave resonance mode. Since the gas cell is supported by a pair of support members formed of a low dielectric constant material at the center position in the cavity resonator, the gas cell is positioned at the center of the TE011 resonance mode. As a result, most of the magnetic field lines of the magnetic field are in the vertical direction in the gas cell. Furthermore, since the support member is made of a low dielectric constant material that is closer to air, the dielectric loss of the microwave is reduced, and the presence of this support member does not significantly degrade the stability of the TE011 resonance mode. .

  Further, the amount of protrusion of the dielectric member having a high dielectric constant for frequency adjustment in the cavity resonator is adjusted by the protrusion amount adjusting mechanism. As described above, by employing a dielectric member having a high dielectric constant, the frequency of the microwave when the TE011 resonance mode is generated can be adjusted more efficiently to the specified frequency with a small protrusion amount. Moreover, the difficulty due to poor contact of screws made of metal is eliminated.

  Further, a part of the antenna is housed in a recess carved in one axial end wall in the cavity resonator. By storing a part of the antenna in the recess in this way, impedance matching between the antenna and the coaxial line (semi-rigid) is facilitated, and the microwave level in the cavity resonator is stabilized.

  Another invention employs rubidium or cesium 133 as the absorbing gas and laser light or lamp light as the light in the microwave cavity resonator of the atomic oscillator according to the invention described above.

  Another invention employs a spherical gas cell as a gas cell in the above-described atomic cavity microwave resonator of the atomic oscillator.

  Another invention employs a cylindrical gas cell as the gas cell in the above-described atomic cavity microwave resonator of the atomic oscillator.

  In the microwave resonator device of the atomic oscillator of the present invention, the TE011 resonance mode is adopted as the microwave resonance mode, and the gas cell is formed at a central position in the cavity resonator by a pair of support members formed of a low dielectric constant material. The frequency adjustment is performed by the amount of protrusion of the dielectric member having a high dielectric constant into the cavity resonator.

  Therefore, the gas cell can be fixed at the center of the cavity resonator, and the influence of each component member existing in the cavity resonator on the frequency of the microwave when the TE011 resonance mode is generated can be selected. A stable TE011 resonance mode having a specified frequency can be generated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a microwave cavity resonator for an atomic oscillator according to a first embodiment of the present invention. FIG. 2A is a top view of the microwave cavity resonator. FIG. 2B is a cross-sectional view of the microwave cavity resonator taken along line AA and viewed from above.

  In the microwave resonator device of the atomic oscillator of the first embodiment, a cylindrical cavity resonator (cavity) 2 is formed in a cylindrical housing 1 made of an aluminum material. The lower end of the cavity resonator 2 is covered with an antenna base 9. In the cavity resonator 2, a spherical gas cell 4 in which an absorption gas of cesium 133 and a buffer gas are enclosed is housed.

  The gas cell 4 includes a ring-shaped upper support member 21 attached to a through-hole 5 formed in the upper wall of the housing 1 and a cylindrical bottom provided in the through-hole 8 of the antenna base 9 so as to be movable up and down. It is supported by the side support member 22. The lower support member 22 is biased upward by a spring 10 fixed to the antenna base 9. Therefore, the gas cell 4 is urged to the upper support member 21 by the spring 10.

  The axial thickness t of the ring-shaped upper support member 21 is set so that the gas cell 4 is positioned at the center of the cavity resonator 2 in the axial direction. The upper support member 21 and the lower support member 22 are made of a low dielectric constant material such as Teflon (registered trademark), for example. The relative dielectric constant ε of the upper support member 21 and the lower support member 22 of the embodiment is 2.1. The relative dielectric constant ε of the gas cell 4 is 4.0.

  FIGS. 3A, 3 </ b> B, and 3 </ b> C are external views of the ring-shaped upper support member 21. In this embodiment, three types of upper support members 21, 21 a, and 21 b are prepared in advance, which have the same axial thickness t but have different outer diameters. Any one of the upper support members 21 (21a, 21b) is selected and incorporated into the microwave cavity resonator when the frequency of the TE011 resonance mode generated in the cavity resonator 2 is adjusted. FIG. 4 is an external view of the cylindrical lower support member 22. There is only one type of the lower support member 22.

  The laser beam 11 as light incident from the outside enters the gas cell 4 through the convex flat lens 17, the through hole 5, and the upper support member 21. The laser beam 11 transmitted through the gas cell 4 enters the light receiver 12 attached to the antenna base 9 via the lower support member 22 and is converted into an electric signal by the light receiver 12.

  Further, in the microwave cavity resonator, in the vicinity of the outer periphery of the antenna base 9 of the cavity resonator 2, as shown in FIG. Has been. An antenna 24 for supplying a microwave for generating a TE011 resonance mode in the cavity resonator 2 is attached in the recess 23. A coaxial connector 13 is connected to the antenna 24.

  As shown in FIGS. 2B and 5A, the antenna 24 is disposed in the circumferential direction of the cavity resonator 2, and the total length of the antenna 24 is one wavelength of the microwave that generates the TE011 resonance mode. Is set to be approximately equal. The tip of the antenna 24 protrudes from the recess 23 into the cavity resonator 2 by about 3 mm. Furthermore, a certain gap exists between the antenna 24 and the side wall 23 a of the recess 23.

  In the antenna 24 arranged in this way, a distributed capacitance (capacitor) exists between the antenna 24 and the side wall 23 a of the recess 23. This distributed capacitance (capacitor) component cancels out the inductive (inductance) component in the impedance of the antenna and the coaxial line (semi-rigid) having the large inductive (inductance) component described above, and the impedance can be made only the resistance component. As a result, impedance matching between the antenna 24 and the coaxial line (semi-rigid) can be easily achieved. The amount of protrusion of the alignment position from the recess 23 of the antenna 24 described above is about 3 mm.

  Then, by setting the protruding amount of the antenna 24 into the cavity resonator 2 to be 3 mm as described above, when the TE011 resonance mode is generated, the input impedance of the antenna 24 can be limited to a resistance component of 50Ω. The level of the microwave becomes stable, and the power level of the microwave supplied from the coaxial connector 13 to the antenna 24 can be reduced.

  Further, since the antenna 24 is arranged in the circumferential direction, as shown in FIG. 5B, the direction of the magnetic field generated by the antenna 24 and the TE011 resonance mode generated in the cavity resonator 2 are generated. The direction of the magnetic field is the same. As a result, the disturbance of the TE011 resonance mode due to the presence of the antenna 24 in the cavity resonator 2 can be suppressed to the minimum.

  FIG. 5C shows the relationship between the shape of the antenna 24 and the waveform of one wavelength (λ) of the microwave signal applied to the antenna 24 via the coaxial connector 13. As shown in the figure, the positions A and C of the antenna 24 indicate the maximum point position (0, 2π) of the waveform of one wavelength (λ), and the intermediate B position of the antenna 24 has the waveform of one wavelength (λ). Indicates the minimum point position (π).

  Further, as shown in FIGS. 1 and 2B, a recess 25 having a circular cross section is formed in the vicinity of the outer peripheral edge of the antenna base 9 of the cavity resonator 2 in this microwave cavity resonator. A dielectric member 26 having a high dielectric constant formed in a cylindrical shape, for example, alumina or the like for adjusting the microwave frequency when the TE011 resonance mode is generated in the cavity resonator 2 is detachably inserted into the recess 25. It is stored. The protrusion amount of the dielectric member 26 having a high dielectric constant to the cavity resonator 2 is implemented by adjusting the screwing amount of the adjustment screw 27 as a protrusion amount adjusting mechanism into the antenna base 9. When the adjustment is completed, the position of the adjustment screw 27 is fixed with the lock nut 28.

  As described above, since the microwave frequency is adjusted by the dielectric member 26 having a high dielectric constant formed in a cylindrical shape with alumina or the like, the microwave when the TE011 resonance mode is generated more efficiently with a small protrusion amount. The frequency can be adjusted to a specified frequency of 9.193263177 GHz when cesium 133 is employed as the absorbing gas. Incidentally, the relative dielectric constant ε of alumina is about 9.6, and the irregular reflection due to the adjusting screw 34 formed of phosphor bronze in the conventional microwave cavity resonator can be reduced. As a result, the disturbance of the TE011 resonance mode caused by the presence of the high dielectric member 26 in the cavity resonator 2 can be minimized.

  Further, a magnetic shield coil 18 for generating a static magnetic field is wound around the outer periphery of the cylindrical housing 1 in the cavity resonator 2 housing the gas cell 4.

Next, the shape composed of the outer diameter and axial length of the cavity resonator 2 in which the TE011 resonance mode is generated will be described.
After the internal structure of the cavity resonator 2 is determined, the frequency at which the TE011 resonance mode is generated when other structural members excluding the antenna 24 are removed, and at the time when the TE011 resonance mode is generated when all the structural members are attached. The difference from the frequency is analyzed by simulation. From the simulation results, it has been found that the presence of the internal structural member increases the dielectric constant and decreases the frequency when the TE011 resonance mode is generated.

  In the previous design, the frequency was adjusted by changing the axial length of the cavity 2 to reduce the frequency, but in this method, the mode was shifted to another mode by moving a few millimeters, causing a mode skip phenomenon. There was a danger.

  Therefore, in the embodiment device, the shape of the cavity resonator 2 is designed to be higher by a decrease in the frequency in advance, and the frequency when the TE011 resonance mode is generated is set to the ideal 9.192633177 GHz described above due to the presence of the internal structure member. Make it close. Since the shape of the cavity resonator 2 is designed based on the basic conditions for generating the TE011 resonance mode as described above, the mode skip phenomenon is hardly generated, and the stability of the TE011 resonance mode is improved.

  Furthermore, as a result of designing the shape of the cavity resonator 2 to be higher by a decrease in frequency in advance, the cavity resonator 2 of the embodiment has a smaller outer diameter than the conventional cavity resonator 31 shown in FIG. It was able to be formed small.

  FIG. 6 shows the internal structural members such as the upper support member 21, the gas cell 4, the lower support member 22, the high dielectric constant dielectric member 26, and the antenna 24 inside the cavity resonator 2 designed under the above conditions. It is a figure which shows the reflection (return) characteristic to the microwave input end when changing the frequency f of the microwave applied in the cavity resonator 2 via the antenna 24 in the accommodated state.

  In this characteristic, the frequency f at the occurrence of the TE011 resonance mode is approximately 9.17 GHz, which is still 22 MHz lower than the ideal 9.192633177 GHz as the reference frequency when cesium 133 is used as the absorption gas. If so, the frequency f when the TE011 resonance mode is generated is set to an ideal 9.192633177 GHz by changing the outer diameter of the upper support member 21 and adjusting the amount of protrusion of the high dielectric member 26 into the cavity resonator 2. Can be easily matched.

Next, the frequency adjustment procedure will be described.
First, the gas cell 4 is mounted, and then the upper support members 21, 21a, and 21b having different outer diameters are mounted in order, and the frequency f when the TE011 resonance mode is generated at that time is measured. Then, one upper support member 21 (21a, 21b) having a frequency f closest to the ideal 9.192633177 GHz is selected and attached to the microwave cavity resonator.

  Next, by changing the screwing amount of the adjusting screw 27 into the antenna base 9 so that the microwave frequency f when the TE011 resonance mode is generated in the cavity resonator 2 coincides with the ideal 9.192263177 GHz. The protrusion amount of the dielectric member 26 having a dielectric constant to the cavity resonator 2 is adjusted. When the adjustment is completed, the position of the adjustment screw 27 is fixed with the lock nut 28.

  As described above, the frequency can be adjusted easily and with high accuracy by adjusting in two steps.

(Second Embodiment)
FIG. 7 is a schematic cross-sectional view showing a schematic configuration of a microwave cavity resonator device of an atomic oscillator according to a second embodiment of the present invention. The same parts as those in the microwave cavity resonator of the atomic oscillator according to the first embodiment shown in FIG.

  In the microwave resonator device of the atomic oscillator of the second embodiment, a cylindrical gas cell 29 is housed in the cavity resonator 2 at the center position. Other configurations are almost the same as those of the microwave cavity resonator of the atomic oscillator according to the first embodiment shown in FIG.

  Features by adopting this cylindrical gas cell 29 will be described with reference to FIGS. FIG. 8A is a schematic diagram showing a positional relationship between the magnetic force line distribution and the spherical gas cell 4 in a state where the TE011 resonance mode is generated in the cavity resonator 2, and FIG. It is a schematic diagram which shows the positional relationship of the magnetic force line distribution and the cylindrical gas cell 29 in the state in which the TE011 resonance mode has occurred.

  As is clear from comparison between FIG. 8A and FIG. 8B, the magnetic field direction of the TE011 resonance mode is almost vertical in the gas cell 29 by adopting the cylindrical gas cell 29. Therefore, there is a possibility that there is almost no π transition component in the Ramsey resonance characteristic, and the frequency stability of the atomic oscillator is further improved.

  FIG. 9 shows the reflection to the microwave input terminal when the frequency f of the microwave applied to the cavity resonator 2 through the antenna 24 is changed in the microwave cavity resonator employing the cylindrical gas cell 29. It is a figure which shows the (return) characteristic. According to this characteristic, the frequency f at which the TE011 resonance mode is generated is 9.358 GHz, which is slightly shifted from the ideal 9.192263177 GHz. However, since the final adjustment is a direction that minimizes the π transition, the adjustment location is obtained when a cylindrical gas cell is used. There is also an advantage that the number of

  It should be noted that the cylindrical gas cell 29 has a variation in frequency stability because the volume of the gas cell with respect to the external pressure is likely to change compared to the spherical gas cell 4. In order to solve this, it is necessary to increase the thickness of the upper and lower ends of the gas cell 29.

  The present invention is not limited to the above-described embodiments. In each embodiment, cesium 133 is employed as the absorbing gas sealed in the gas cells 4 and 29, but rubidium and other absorbing gases can be employed.

  Furthermore, in each embodiment, the laser beam 11 is employed as the light incident on the cavity resonator 2, but lamp light can be employed instead of the laser beam 11.

1 is a schematic cross-sectional view showing a schematic configuration of a microwave cavity resonator for an atomic oscillator according to a first embodiment of the present invention. Top view and horizontal sectional view of the microwave cavity resonator Perspective view of upper support member incorporated in same microwave cavity resonator A perspective view of a lower support member incorporated in the microwave cavity resonator The figure which shows the antenna built in the microwave cavity resonator and its operation Microwave reflection and frequency characteristics in the microwave cavity resonator Sectional model which shows schematic structure of the microwave cavity resonance apparatus of the atomic oscillator concerning 2nd Embodiment of this invention. The figure which shows the feature of the gas cell built in the same microwave cavity resonator Microwave reflection and frequency characteristics in the microwave cavity resonator Cross-sectional schematic diagram showing the schematic configuration of a conventional microwave cavity resonator device of an atomic oscillator

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Housing, 2 ... Cavity resonator, 4,29 ... Gas cell, 9 ... Antenna base, 10 ... Spring, 11 ... Laser beam, 12 ... Light receiver, 13 ... Coaxial connector, 17 ... Convex lens, 18 ... Magnetic shield Coil, 21, 21a, 21b ... upper support member, 22 ... lower support member, 23, 25 ... recess, 24 ... antenna, 26 ... high dielectric constant dielectric member, 27 ... adjustment screw, 28 ... lock nut

Claims (4)

A cylindrical cavity resonator (2) formed in a metal body, a gas cell (4, 29) enclosed in the cavity resonator and enclosing an absorption gas and a buffer gas, and TE011 in the cavity resonator Microwave cavity resonance of an atomic oscillator having an antenna (24) for supplying a microwave for generating a resonance mode and a light receiver (12) for receiving light (11) incident from the outside and transmitted through the gas cell In the device
A pair of support members (21, 22) provided in the vicinity of both axial ends in the cylindrical cavity resonator and formed of a low dielectric constant material that supports the gas cell at a central position in the cavity resonator. When,
A dielectric member (26) having a high dielectric constant that is detachably provided in the cavity resonator;
The amount of protrusion of the high dielectric constant dielectric member into the cavity resonator from one end surface in the axial direction in the cavity resonator is set so that the frequency of the microwave when the TE011 resonance mode is generated becomes a specified frequency. A protrusion amount adjusting mechanism (27) to be adjusted;
An atomic oscillator micro, comprising: a concave portion (23) engraved on one end wall of the cavity resonator in an axial direction and storing a part of the antenna with a gap with respect to the side wall. Wave cavity resonance device.   The microwave cavity resonator for an atomic oscillator according to claim 1, wherein the absorbing gas is rubidium or cesium 133, and the light is laser light or lamp light.   The microwave cavity resonator for an atomic oscillator according to claim 1 or 2, wherein the gas cell has a spherical shape.   3. The microwave cavity resonance apparatus for an atomic oscillator according to claim 1, wherein the gas cell has a cylindrical shape.

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