JP2009089116A - Optical module for atomic oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve performance of an atomic oscillator without enlarging the total length of a gas cell or shorten the total length of a conventional gas cell and miniaturize the optical module. <P>SOLUTION: The optical module 31 has a structure, in which a light emitting element 33 and a light receiving element 34 at each predetermined position of a base substrate 32, a passive optical element 36 serving as light conductive means through a spacer 35, a gas cell 37 with enclosed metallic atom in gas state, and a trapezoidal prism 38 are laminated sequentially. Reflecting film 42a, 42b are formed at each predetermined position of two slanted portions of the trapezoidal prism 38 so that incident light is reflected at a predetermined angle. Reflecting film 43a, 43b are formed on each opposite side face in an elongated direction of the gas cell 37, and thereby light is subjected to multiple reflection at a predetermined angle and spread when the incident light propagates. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical module for an atomic oscillator, and more particularly to an improvement in performance of an optical module composed of a light emitting element, a light receiving element, a gas cell, and the like, as well as a reduction in size and thickness.

An atomic oscillator using an alkali metal such as rubidium or cesium needs to keep the metal atom in a gas state when utilizing the energy transition of the atom. Therefore, the gas cell in which the metal atom is hermetically sealed is kept operating at a high temperature. ing. The operation principle of an atomic oscillator is roughly classified into a double resonance method using light and microwaves, and a method using a quantum interference effect (hereinafter referred to as CPT: Coherent Population Trapping) using two types of laser light. Both methods detect the atomic resonance by detecting how much light incident on the gas cell is absorbed by the metal atomic gas, and detect the atomic resonance in the control system. An output is obtained by synchronizing a reference signal such as this with the atomic resonance.
The operation principle of an atomic oscillator using a gas cell is described in detail in Patent Document 1. In many cases, an atomic oscillator using the CPT integrally forms a light emitting element, a gas cell, and a light receiving element to form an optical system module. Is disclosed.

As a conventional optical module, there is a structure disclosed in Patent Document 3, and a method of configuring an optical module using CPT by a method different from the structure of the optical module shown in Patent Document 2 will be described. ing. According to this, the light emitting element is arranged at the center of one of the opposing surfaces of the cylindrical gas cell, and the light receiving element is arranged so as to surround the light emitting element. A light plate is provided on the other surface of the gas cell, the light emitted from the light emitting element disposed on the one surface of the gas cell is reflected on the other surface of the gas cell, and the reflected light is reflected on one side of the gas cell. The light is incident on a light receiving element arranged on the surface.
JP 2004-96410 A US6808064B2 US7064835B2

However, the conventional optical module disclosed in Patent Document 2 has the following problems. As described above, the operation principle of the atomic oscillator is that atomic resonance is detected by detecting how much light incident on the gas cell in which the metal atoms are hermetically sealed is absorbed by the metal atom gas by the photodetector provided on the opposite side. Is to detect. Therefore, in order to improve the performance of the atomic oscillator, it is desirable to increase the level difference between when light is absorbed and when light is not absorbed when light incident on the gas cell is detected on the opposite side. For this purpose, it is necessary to increase the contact time between the light and the metal atomic gas. For this reason, the optical path of light when the light propagates in the gas cell is lengthened, and the metal atomic gas in contact with the light is increased. It is desirable.
On the other hand, the structure of the conventional optical module shown in Patent Document 2 is such that each component is arranged vertically, and the light emitting element and the light receiving element are opposed to each other. If the total length of the gas cell is increased in order to lengthen the optical path of light, there is a problem that the optical module becomes large.

FIG. 6 shows a structural diagram of a conventional optical module for an atomic oscillator. As shown in FIG. 6, in the conventional optical module 101, the light emitting element 102, the passive optical element 103, the gas cell 104, and the light receiving element 105 are arranged vertically, and the light emitting element 102 and the light receiving element 105 are arranged to face each other. . The passive optical element 103 includes an ND filter, a lens, and a wave plate for condensing the light emitted from the light emitting element 102 and changing the polarization state. The schematic operation of the optical module 101 will be described. The coherent light 106 emitted from the light-emitting element 102 is input to the passive optical element 103, collects and polarizes the coherent light 106, and enters the gas cell 104. The gas cell 104 operates such that light absorption stops when the wavelength of one or both of the coherents 106 having two wavelengths is changed. The transmitted light that has passed through the gas cell 104 is received by the light receiving element 105. The conventional optical module 101 that operates in this manner has a problem when the length of the gas cell 104 is increased in order to improve the performance of the atomic oscillator. It was. Further, if the total length of the gas cell 104 is kept short in order to reduce the size and thickness of the atomic oscillator, the atomic oscillator has a problem that it is susceptible to noise and deteriorates the S / N characteristics.
The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the performance of an atomic oscillator without increasing the total length of a gas cell.
Another object of the present invention is to make the optical module smaller and thinner by shortening the overall length of the conventional gas cell.

In order to achieve the above object, the present invention provides an optical system for an atomic oscillator that controls an oscillation frequency by utilizing a light absorption characteristic due to a quantum interference effect when two types of resonance light as coherent light having different wavelengths are incident. A light-emitting element that emits light as the resonance light, a light-receiving element that detects the quantum-interfered light, and a light source that encloses gaseous metal atoms and causes quantum interference between incident light and a longitudinal direction A gas cell having a reflective film formed on a side surface and a trapezoidal prism having a reflective film formed on an inclined portion; and the light emitted from the light emitting element is reflected by the trapezoidal prism and is incident on the gas cell; The light incident on the gas cell is propagated by being reflected by the reflection film formed on the side surface in the longitudinal direction of the gas cell, and the propagated light is transmitted to the trapezoidal prism. And so as to be incident on the light receiving element is reflected by the serial reflective film.
According to the present invention, since the light emitted from the light emitting element is propagated while multiply-reflecting the side surfaces facing in the longitudinal direction in the gas cell, the light emitted from the light emitting element in the gas cell as in the conventional case. The optical path of light propagating in the gas cell is longer than when propagating straight as it is. Therefore, the time during which the light and the metal atomic gas are in contact with each other increases, and the performance of the atomic oscillator can be improved without increasing the total length of the gas cell.
Further, by using the gas cell according to the present invention, the total length can be shortened as compared with the conventional gas cell, and the shape of the optical module can be reduced, and the atomic oscillator can be reduced in size and thickness.

Further, the present invention is an optical module for an atomic oscillator that controls an oscillation frequency using light absorption characteristics due to a quantum interference effect when two types of resonant light as coherent light having different wavelengths are incident. A light-emitting element that emits light that becomes resonance light, a light-receiving element that detects the quantum-interfered light, and encapsulates gaseous metal atoms to cause quantum interference of incident light and to form a reflective film on the side surface in the longitudinal direction A gas cell, and prisms provided on both sides of the gas cell in the short-side direction, each of which has a reflecting film formed on an inclined portion, and the light emitted from the light emitting element is reflected by the prism so as to be reflected in the gas cell. The light incident on the gas cell is propagated by being reflected by the reflective film formed on the side surface in the longitudinal direction in the gas cell, and the propagated light is transmitted to the gas cell. Is reflected by the rhythm is characterized in that so as to be incident on the light receiving element.
According to the present invention, since the light emitted from the light emitting element is propagated while multiply-reflecting the side surfaces facing in the longitudinal direction in the gas cell, the light emitted from the light emitting element in the gas cell as in the conventional case. The optical path of light propagating in the gas cell is longer than when propagating straight as it is. Therefore, the time during which the light and the metal atomic gas are in contact with each other increases, and the performance of the atomic oscillator can be improved without increasing the total length of the gas cell.

Further, by using the gas cell according to the present invention, the total length can be shortened as compared with the conventional gas cell, and the shape of the optical module can be reduced, and the atomic oscillator can be reduced in size and thickness.
In addition, according to the present invention, the light emitted from the light emitting element is reflected so that the reflected light is incident on the gas cell, or the two prisms that reflect the light emitted from the gas cell and enter the light receiving element are arranged in the short side of the gas cell. The atomic oscillator can be further reduced in thickness by being arranged on both sides in the direction.
Further, the present invention is characterized in that the reflective film is made of a metal film.
According to the present invention, a metal film is used as the reflection film, and the metal film has a simple film formation process. Therefore, an inexpensive optical module is configured by using the metal film as the reflection film. can do.

Further, the present invention is characterized in that the reflection film is made of a dielectric multilayer film.
According to the present invention as described above, the dielectric multilayer film is used as the reflective film, and the dielectric multilayer film has excellent reflection efficiency and can maintain the polarization state of the reflected light. Therefore, an optical module having excellent performance can be configured by using a dielectric multilayer film as the reflective film.
Further, the present invention is characterized in that the coherent light is laser light.
According to the present invention as described above, a laser is used as a light emitting element that causes light to enter a gas cell to cause quantum interference. Therefore, since the light emitted from the laser has good monochromaticity in wavelength and good coherence in phase, the optical module can realize an excellent quantum interference effect.
In addition, the present invention is characterized in that the gaseous metal atom is rubidium or cesium.
According to the present invention, when a cesium atom is used as a gaseous metal atom, a highly accurate atomic oscillator can be realized. In addition, when rubidium atoms are used as gaseous metal atoms, an inexpensive atomic oscillator can be realized. Therefore, any metal atom can be selected in consideration of the required performance and cost of the atomic oscillator.

FIG. 1 is a block diagram showing a main configuration of an optical system of an atomic oscillator. The atomic oscillator 1 includes a gas cell 4 in which gaseous metal atoms are sealed, a coherent light source 3 that supplies resonance light to the metal atom gas in the gas cell 4, and a first light that guides light emitted from the coherent light source 3 to the gas cell 4. Light guide means 8, second light guide means 9 for guiding the transmitted light 7 transmitted through the gas cell 4 to the photodetector 5, and light detection for detecting the transmitted light 7 guided by the second light guide means 9. And an optical module 2 comprising a detector 5 and a frequency control circuit 6 for controlling the oscillation frequency based on a signal detected by the photodetector 5. Here, detailed description of the frequency control of the atomic oscillator is omitted.
The atomic oscillator 1 utilizes quantum interference of coherent light such as laser light. When two types of resonance light as coherent light having different wavelengths are incident on the gas cell 4, light absorption characteristics due to the quantum interference effect are obtained. Is used to control the oscillation frequency. In this system, in a system in which two ground levels receive resonance light and are resonantly coupled with a common excitation level, the frequency of the two resonance lights irradiated at the same time is accurately set to the first ground level. When the energy difference between the second ground levels coincides, the atom becomes a superposition of the two ground levels, and the excitation to the excited level stops. CPT uses this principle to detect a state in which light absorption in the gas cell 4 stops when the wavelength of one or both of the two resonance lights is changed.

  FIG. 2 is an example of a diagram illustrating a three-level system of atoms by the CPT method. The rubidium and cesium ground levels used in the atomic oscillator are divided into two kinds of ground levels by the hyperfine structure due to the nuclear spin-electron spin interaction. These ground level atoms absorb light and excite to higher energy levels. A state in which two ground levels receive light and are resonantly coupled to a common excitation level as shown in FIG. 2 is called two-photon resonance. In FIG. 2, since the first ground level 23 and the second ground level 24 have slightly different level energies, the resonance light also has a wavelength different from that of the first resonance light 20 and the second resonance light 22, respectively. Slightly different. When the frequency difference (wavelength difference) between the first resonant light 20 and the second resonant light 22 irradiated at the same time exactly matches the energy difference between the first ground level 23 and the second ground level 24, The system of FIG. 2 is in a superposition state of two ground levels, and excitation to the excitation level 21 stops. The CPT utilizes this principle to absorb light in the gas cell 4 when the wavelength of one or both of the first resonance light 20 and the second resonance light 22 is changed (that is, to the excitation level 21). This is a method of detecting and using a state where the conversion is stopped.

Next, specific embodiments of the optical module according to the present invention will be described.
FIG. 3 is a diagram schematically showing the configuration of the optical module according to the first embodiment of the present invention. The optical module 31 includes a light-emitting element (coherent light source) 33 and a light-receiving element (photodetector) 34 mounted at predetermined positions on the base substrate 32, and a passive optical element 36 serving as a light guide unit via a spacer 35. The gas cell 37 in which gaseous metal atoms are enclosed and the trapezoidal prism 38 are sequentially stacked. The passive optical element 36 includes an ND filter 39, a lens 40, and a wave plate 41 for condensing the light emitted from the light emitting element 33 and changing the polarization state.
Reflecting films 42a and 42b are formed on the two inclined portions of the trapezoidal prism 38 so as to reflect incident light at a predetermined angle. Reflecting films 43a and 43b are formed on the opposite side surfaces of the gas cell 37 in the longitudinal direction so as to propagate the incident light by multiple reflection at a predetermined angle.

Next, a schematic operation of the optical module 31 shown in FIG. 3 will be described. The coherent light 44a emitted from the light emitting element 33 is incident on the passive optical element 36, the light amount is adjusted by the ND filter 39 that changes the transmittance, and then condensed by the lens 40, and further polarized by the wave plate 41. The light enters the gas cell 37. The coherent light 44 a passes through the gas cell 37 as it is and enters the trapezoidal prism 38. The incident coherent light 44 a is reflected by the reflection film 42 a formed on one inclined portion of the trapezoidal prism 38 and is incident on the gas cell 37. The angle of one inclined portion of the trapezoidal prism 38 is such that when the incident coherent light 44a is reflected, the reflected coherent light 44b is reflected at a predetermined angle on the reflective film 43a formed on the side surface in the longitudinal direction of the gas cell 37. It is set to enter.
Next, the coherent light 44b incident on the gas cell 37 is reflected by the reflective film 43a and incident on the reflective film 43b formed on the opposite side surface. The coherent light 44b incident on the reflective film 43b is further reflected at a predetermined angle and incident on the reflective film 43a formed on the opposite side surface, and propagates in the gas cell 37 with multiple reflections. The gas cell 37 operates so that light absorption stops when either or both of the coherent lights 44b having two wavelengths are changed.

Next, the coherent light 44 b incident on the reflective film 43 a is reflected at a predetermined angle, passes through the gas cell 37, and enters the trapezoidal prism 38. The incident coherent light 44b is reflected at a predetermined angle by the reflective film 42b formed on the other inclined portion of the trapezoidal prism 38. The angle of the other inclined portion of the trapezoidal prism 38 is set so that the reflected coherent light 44c propagates on the optical axis of the light receiving element 34 when the incident coherent light 44b is reflected. Therefore, the coherent light 44 c reflected by the reflective film 42 b formed on the other inclined portion of the trapezoidal prism 38 passes through the gas cell 37 and is received by the light receiving element 34 via the passive optical element 36 described above.
As described above, according to the first embodiment, the coherent light 44b propagates while multiply-reflecting the side surfaces facing in the longitudinal direction in the gas cell 37, and in the conventional optical module, the coherent light travels straight through the gas cell. Therefore, the optical path of the coherent light 44b in the gas cell 37 becomes longer than the case of propagating as it is. Therefore, the time during which the coherent light 44b and the metal atomic gas are in contact with each other is increased, and the performance of the atomic oscillator can be improved without increasing the total length of the gas cell. In addition, by using the gas cell according to the first embodiment, the total length of the conventional gas cell can be shortened, the shape of the optical module can be reduced, and the atomic oscillator can be reduced in size and thickness. .

Next, the reflection films 42a and 42b formed on the trapezoidal prism 38 and the reflection films 43a and 43b formed on the gas cell 37 will be described.
In general, as a means for forming a reflective film on an optical element, there are a method of forming a metal film and a method of forming a dielectric multilayer film, which are used taking advantage of their respective characteristics.
As a reflection film using a metal film, a film in which a protective film is formed on the surface after a metal material such as aluminum is deposited is often used. The metal film is simpler and cheaper than the case where the formation process is a multilayer film. The light reflected by the metal film has a property of rotating the polarization direction, and is used in consideration of the property.
Next, the reflective film using the dielectric multilayer film is one in which two or three kinds of dielectric materials are alternately laminated in a multilayer and function as a reflective film due to the light interference effect. The dielectric multilayer film is more complicated in manufacturing process than the metal film described above and is more expensive than the metal film. However, the light reflected by the dielectric multilayer film does not rotate in the polarization direction. Have.

FIG. 4 is a diagram schematically showing a configuration in the case where a dielectric multilayer film is formed as a reflective film in the gas cell. As shown in FIG. 4, reflection films 43 a and 43 b made of a dielectric multilayer film are formed on the opposite side surfaces of the gas cell 37 in the longitudinal direction. The reflective films 43a and 43b are formed, for example, by alternately depositing a low refractive index dielectric material and a high refractive index dielectric material in multiple layers, and a low refractive index dielectric material and a high refractive index dielectric. By adjusting the film thickness of the material, an extremely high reflectance is obtained.
As in the present invention, when light is incident into a gas cell in which gaseous metal atoms are sealed to generate the CPT phenomenon, it is possible to generate a larger CPT phenomenon by aligning the polarization direction of the incident light. It is said. Therefore, when forming a reflective film on the optical module according to the present invention, a metal film or a dielectric multilayer film may be appropriately selected in consideration of the performance and cost of the optical module.

Next, a second embodiment of the optical module according to the present invention will be described. In the second embodiment, the prism that bends the light emitted from the light emitting element into the gas cell is not disposed on the surface of the gas cell as in the first embodiment, but is disposed on the side surface on the short side of the gas cell. Is a feature. Therefore, the thickness can be further reduced as compared with the first embodiment.
FIG. 5 is a diagram schematically showing a configuration of an optical module according to the second embodiment of the present invention. The optical module 51 includes a light-emitting element (coherent light source) 53 and a light-receiving element (photodetector) 54 mounted at predetermined positions on the base substrate 52, and a passive optical element 56 serving as a light guide unit via a spacer 55. In this structure, gas cells 57 filled with gaseous metal atoms are sequentially stacked. In addition, prisms 59a and 59b are disposed on the side surfaces on the short side of the gas cell 57 via optical blocks 58a and 58b, respectively. The passive optical element 56 includes an ND filter 60, a lens 61, and a wave plate 62 for condensing the light emitted from the light emitting element 53 and changing the polarization state.
Reflective films 63a and 63b are formed on the inclined portions of the prisms 59a and 59b, respectively, so that incident light is reflected at a predetermined angle. Reflecting films 64a and 64b are formed on the opposite side surfaces of the gas cell 57 in the longitudinal direction, and the incident light is propagated by multiple reflection at a predetermined angle.

Next, a schematic operation of the optical module 51 will be described with reference to FIG. The coherent light 65 a emitted from the light emitting element 53 is incident on the passive optical element 56, the amount of light is adjusted by the ND filter 60 that changes the transmittance, and then condensed by the lens 61 and further polarized by the wave plate 62. The light passes through the optical block 58a and enters the prism 59a. A reflection film 63a is formed on the inclined portion of the prism 59a, and the angle of the inclined portion of the prism 59a is such that the reflected coherent light 65b is reflected in the longitudinal direction of the gas cell 57 when the incident coherent light 65a is reflected. It is set so as to be incident at a predetermined angle on the reflection film 64a formed on the side surface of the film.
The coherent light 65b reflected by the reflective film 63a formed on the inclined portion of the prism 59a enters the gas cell 57, is reflected by the reflective film 64a, and enters the reflective film 64b formed on the opposite side surface. The coherent light 65b incident on the reflective film 64b is reflected at a predetermined angle and is incident on the reflective film 64a formed on the opposite side surface. The coherent light 65b incident on the reflection film 64a is reflected by the reflection film 64a and incident on the reflection film 64b formed on the opposite side surface, and further reflected at a predetermined angle and formed on the opposite side surface. 64a. The coherent light 65b is reflected at a predetermined angle, passes through the gas cell 57, and enters the prism 59b. As described above, the coherent light 65 b incident on the gas cell 57 propagates through the gas cell 57 with multiple reflection. Further, the gas cell 57 operates so that the light absorption is stopped when either or both of the coherent lights 65b having the two wavelengths are changed.

A reflection film 63b is formed on the inclined portion of the prism 59b, and the coherent light 65b is reflected at a predetermined angle. The angle of the inclined portion of the prism 59b is set so that the reflected coherent light 65c propagates on the optical axis of the light receiving element 54 when the incident coherent light 65b is reflected. Therefore, the coherent light 65c passes through the optical block 58b and is received by the light receiving element 54 via the passive optical element 56 described above.
Thus, according to the second embodiment, the coherent light 65b propagates while multiply-reflecting the opposite side surfaces in the longitudinal direction in the gas cell 57, and in the conventional optical module, the coherent light is linear in the gas cell. Therefore, the optical path of the coherent light 65b in the gas cell 57 is longer than the case of propagating as it is. Therefore, it is possible to improve the performance of the atomic oscillator without increasing the total length of the gas cell by increasing the time during which the coherent light 65b is in contact with the metal atomic gas. Further, by using the gas cell according to the second embodiment, the total length of the conventional gas cell can be shortened, and the shape of the optical module can be reduced, and the atomic oscillator can be reduced in size and thickness. . In the second embodiment, since the prisms that reflect the coherent light and enter the gas cell are arranged on both side surfaces of the short side of the gas cell, the optical module is further reduced in thickness compared to the first embodiment. It becomes possible.

Further, as the reflective film formed on the optical module 51, the above-described metal film or dielectric multilayer film may be appropriately selected and used. The reflective films 64a and 64b formed on the gas cell 57 may be formed on the entire side surface in the longitudinal direction of the gas cell 57, or may be formed only at a predetermined position.
Note that the light-emitting element described in this embodiment is preferably a laser that emits coherent light. Laser light has good monochromaticity in wavelength and has a uniform phase. Coherence is defined as a measure of the stability of the wavelength and phase of light. Since light with good coherence, that is, with stable wavelength and phase, can cause quantum interference effects, laser light is optimal in that respect.
The gaseous metal atom used in the gas cell described in this embodiment is rubidium or cesium. For example, a cesium atom used in a primary atom standard can be used to realize a highly accurate atomic oscillator. The rubidium atom used in the secondary standard is easily and widely used, so it can be used to realize a small and low-priced atomic oscillator. Therefore, what is used as the metal atom may be selected according to the purpose of use. In the present embodiment, rubidium and cesium are used as metal atoms, but any atom may be used as long as it has a three-level system.

It is the block diagram which showed the principal part structure of the optical system of an atomic oscillator. It is an example of the figure explaining the three-level system of atoms by a CPT system. It is the figure which showed typically the structure of the optical module which concerns on the 1st Embodiment of this invention. It is the figure which showed typically the structure at the time of forming a dielectric multilayer film as a reflecting film in a gas cell. It is the figure which showed typically the structure of the optical module which concerns on the 2nd Embodiment of this invention. It is the figure which showed the structure of the optical module for conventional atomic oscillators.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Atomic oscillator, 2, 31, 51 ... Optical module, 3 ... Coherent light source 4, 37, 57 ... Gas cell, 5 ... Photodetector, 6 ... Frequency control circuit, 7 ... Transmitted light, 8 ... First guide Light means, 9 ... second light guide means, 20 ... first resonance light, 21 ... excitation level, 22 ... second resonance light, 23 ... first ground level, 24 ... second ground level 32, 52 ... base substrate, 33, 53 ... light emitting element, 34, 54 ... light receiving element, 35, 55 ... spacer, 36, 56 ... passive optical element, 38 ... trapezoid prism, 39, 60 ... ND filter, 40 , 61 ... lens, 41, 62 ... wave plate, 42a, 42b, 43a, 43b, 63a, 63b, 64a, 64b ... reflective film, 44a, 44b, 44c, 65a, 65b, 65c ... coherent light, 58a, 58b ... Optical block, 59a, 59b ... Rhythm

Claims (6)

An optical module for an atomic oscillator that controls an oscillation frequency by utilizing light absorption characteristics due to a quantum interference effect when two types of resonant light as coherent lights having different wavelengths are incident.
A light emitting element that emits light that becomes the resonance light, a light receiving element that detects the quantum-interfered light, a quantum metal interference between incident light encapsulating gaseous metal atoms, and a reflective film on the side surface in the longitudinal direction A formed gas cell, and a trapezoidal prism having a reflective film formed on the inclined portion,
The light emitted from the light emitting element is reflected by the trapezoidal prism and is incident on the gas cell, and the light incident on the gas cell is multiple-reflected by the reflective film formed on the side surface in the longitudinal direction of the gas cell. An optical module for an atomic oscillator, wherein the propagated light is reflected by the reflective film of the trapezoidal prism and is incident on the light receiving element. An optical module for an atomic oscillator that controls an oscillation frequency by utilizing light absorption characteristics due to a quantum interference effect when two types of resonant light as coherent lights having different wavelengths are incident.
A light emitting element that emits light that becomes the resonance light, a light receiving element that detects the quantum-interfered light, a quantum metal interference between incident light encapsulating gaseous metal atoms, and a reflective film on the side surface in the longitudinal direction A gas cell formed, and a prism provided on each of both sides of the gas cell in the short-side direction, and having a reflecting film formed on the inclined portion,
The light emitted from the light emitting element is reflected by the prism and is incident on the gas cell, and the light incident on the gas cell is multiple-reflected by the reflective film formed on the side surface in the longitudinal direction of the gas cell. An optical module for an atomic oscillator, wherein the propagated light is reflected by the prism and is incident on the light receiving element.   The optical module for an atomic oscillator according to claim 1, wherein the reflective film is made of a metal film.   The optical module for an atomic oscillator according to claim 1, wherein the reflective film is made of a dielectric multilayer film.   The optical module for an atomic oscillator according to any one of claims 1 to 4, wherein the coherent light is laser light.   The optical module for an atomic oscillator according to any one of claims 1 to 5, wherein the gaseous metal atom is rubidium or cesium.

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