JP6662061B2 - Quantum interference devices, atomic oscillators, electronic equipment and moving objects - Google Patents

Description

  The present invention relates to a quantum interference device, an atomic oscillator, an electronic device, and a moving object.

  As an oscillator having high-precision oscillation characteristics in the long term, an atomic oscillator that oscillates based on energy transition of atoms of an alkali metal such as rubidium and cesium is known.

  Generally, the operating principle of an atomic oscillator is roughly divided into a method using a double resonance phenomenon by light and a microwave, and a method using a quantum interference effect (CPT: Coherent Population Trapping) by two kinds of light having different wavelengths. Is done. Since an atomic oscillator using the quantum interference effect can be made smaller than an atomic oscillator using the double resonance phenomenon, it is expected that it is mounted on various devices in recent years (for example, see Patent Document 1).

  An atomic oscillator utilizing the quantum interference effect includes, for example, a gas cell (atomic cell) in which a gaseous alkali metal is sealed and a resonance light pair for resonating the alkali metal in the gas cell as disclosed in Patent Document 1. A light source that emits light, and a photodetector (photodetector) that detects a pair of resonance light transmitted through the gas cell are provided. In such an atomic oscillator, an EIT (Electromagnetically Induced Transparency) phenomenon occurs in which two types of resonance light having a specific frequency difference are transmitted without being absorbed by the alkali metal in the gas cell. Although it occurs, an EIT signal, which is a steep signal generated by the EIT phenomenon, is detected by a photodetector, and oscillation is performed using the EIT signal.

JP 2014-17824 A

  Here, from the viewpoint of increasing the short-term frequency stability, the EIT signal preferably has a small line width (half width) and a high intensity. Therefore, for example, the atomic oscillator according to Patent Document 1 uses a circularly polarized resonance light pair for the purpose of improving the intensity of the EIT signal.

  However, in the atomic oscillator according to Patent Document 1, since only the resonance light pair circularly polarized in the same direction irradiates the alkali metal in the gas cell, the magnetic quantum number distribution of the alkali metal is biased. . Therefore, the number of metal atoms having a desired magnetic quantum number that contributes to the EIT decreases, and as a result, the intensity of the EIT signal cannot be sufficiently improved.

  An object of the present invention is to provide a quantum interference device capable of effectively improving the intensity of an EIT signal, and to provide an atomic oscillator, an electronic device, and a moving object including the quantum interference device.

The above object is achieved by the present invention described below.
The quantum interference device of the present invention, an atomic cell having an internal space in which alkali metal atoms are enclosed,
A first light source unit that emits a resonance light pair that circularly polarizes in the same direction and excites the alkali metal atom,
A second light source that emits adjustment light that excites the alkali metal atom by circularly polarizing in the opposite direction to the resonance light pair in the internal space,
A light detection unit that detects the resonance light pair and the adjustment light that have passed through the internal space, and outputs a signal corresponding to the detected intensity.
A first detection unit that detects an output signal of the light detection unit and outputs a first signal using a signal of a first frequency;
A second detection unit that detects an output signal of the light detection unit and outputs a second signal by using a signal of a second frequency different from the first frequency;
A third detection unit that detects an output signal of the light detection unit and outputs a third signal by using a signal having a third frequency different from the first frequency and the second frequency. I do.

  According to such a quantum interference device, in addition to the resonance light pair circularly polarized in the same direction as each other, the adjustment light circularly polarized in the rotation direction opposite to the resonance light pair in the atom cell is adjusted. By irradiating the alkali metal atoms in the atomic cell, the bias of the magnetic quantum number distribution due to the resonance light pair can be offset or relaxed by the adjustment light, and the bias of the magnetic quantum number distribution of the alkali metal atoms can be reduced. . Therefore, the number of metal atoms having a desired magnetic quantum number that contributes to the electromagnetic induction transmission phenomenon (EIT) is increased, and as a result, the effect of improving the intensity of the EIT signal by using a circularly polarized resonance light pair is obtained. It can be significantly expressed. Therefore, the intensity of the EIT signal can be effectively improved.

  Here, since the first frequency, the second frequency, and the third frequency are different from each other, the first light detection unit, the second detection unit, and the third detection unit are used to calculate the resonance light pair from the output signal of one light detection unit. , A signal related to the center wavelength (center frequency), the wavelength (frequency) of the adjustment light, and the wavelength difference (frequency difference) between the resonance light pair can be detected separately. Therefore, using the signals of these detectors, it is possible to stabilize the respective wavelengths and oscillation frequencies of the resonance light pair and the adjustment light.

  The quantum interference device of the present invention preferably includes a first drive circuit that drives the first light source unit using the first signal and the third signal.

  Accordingly, the first drive circuit can drive the first light source unit by superimposing the bias current based on the first signal and the modulation current based on the third signal and inputting the superimposed current to the first light source unit. The center wavelength of the resonance light pair can be stabilized by the bias current based on the first signal, and the frequency difference between the resonance light pairs can be stabilized by the modulation current based on the third signal.

  In the quantum interference device according to the aspect of the invention, it is preferable that the quantum interference device further include a second drive circuit that drives the second light source unit using the second signal.

  Thus, the second drive circuit can drive the second light source unit by inputting the bias current based on the second signal to the second light source unit. Then, the wavelength of the adjustment light can be stabilized by the bias current based on the second signal.

  The quantum interference device of the present invention preferably includes an oscillator that outputs a clock signal using the third signal.

  Thus, the oscillator can output a clock signal having a frequency based on the third signal.

  In the quantum interference device of the present invention, it is preferable that the third frequency is higher than the first frequency and the second frequency.

  The line width of the EIT signal of the alkali metal atom is smaller than the line width of the absorption spectrum of the alkali metal atom. Therefore, by setting the third frequency higher than the first frequency and the second frequency, the signal relating to the frequency difference between the pair of resonance light and the signal relating to the center wavelength of the pair of resonance light and the wavelength of the adjustment light can be easily obtained in the third detection unit. Can be detected separately.

  In the quantum interference device of the present invention, it is preferable that the resonance light pair is a D1 line and the adjustment light is a D2 line.

  Thus, the EIT phenomenon caused by the adjustment light can be reduced, and the intensity of the EIT signal can be efficiently improved.

  In the quantum interference device of the present invention, it is preferable that each of the first light source unit and the second light source unit has a surface emitting laser.

  This makes it possible to easily generate the resonance light pair and the adjustment light having a desired frequency.

An atomic oscillator according to the present invention includes the quantum interference device according to the present invention.
Thereby, it is possible to provide an atomic oscillator including the quantum interference device that can effectively improve the intensity of the EIT signal.

An electronic device according to the present invention includes the quantum interference device according to the present invention.
Accordingly, it is possible to provide an electronic device including the quantum interference device that can effectively improve the intensity of the EIT signal.

A mobile object according to the present invention includes the quantum interference device according to the present invention.
Accordingly, it is possible to provide a moving object including the quantum interference device that can effectively improve the intensity of the EIT signal.

FIG. 1 is a schematic diagram illustrating an atomic oscillator (quantum interference device) according to an embodiment of the present invention. FIG. 3 is a diagram for simply explaining an energy state of an alkali metal atom. 9 is a graph illustrating a relationship between a frequency difference between two lights emitted from the light source unit and an intensity of light detected by the light detection unit. It is a figure which shows an example of the relationship between the energy state of a cesium atom, a resonance light pair (1st resonance light, 2nd resonance light), and adjustment light (3rd resonance light). A diagram showing a magnetic quantum number of the distribution of sodium atoms, (a) represents a diagram showing a distribution of when irradiated with resonant light of sigma ₊ circularly polarized light, (b), the sigma _- a circularly polarized resonant light It is a figure which shows the distribution at the time of irradiation. It is a figure explaining the D1-line absorption spectrum of an alkali metal atom (cesium atom). It is a figure explaining the relation between D1 line absorption spectrum of an alkali metal atom (cesium atom), and the frequency of a resonance light pair. It is a figure explaining the D2-line absorption spectrum of an alkali metal atom (cesium atom). FIG. 4 is a diagram illustrating a relationship between a D2 line absorption spectrum of an alkali metal atom (cesium atom) and a frequency of adjustment light. FIG. 3 is a diagram illustrating an EIT spectrum of an alkali metal atom (cesium atom). FIG. 1 is a diagram illustrating a schematic configuration in a case where an atomic oscillator of the present invention is used in a positioning system using a GPS satellite. It is a figure showing an example of a mobile of the present invention.

  Hereinafter, a quantum interference device, an atomic oscillator, an electronic device, and a moving object of the present invention will be described in detail based on embodiments shown in the accompanying drawings.

1. Atomic oscillator (quantum interference device)
First, the atomic oscillator of the present invention (atomic oscillator including the quantum interference device of the present invention) will be described. In the following, an example in which the quantum interference device of the present invention is applied to an atomic oscillator will be described. However, the quantum interference device of the present invention is not limited to this, and may be applied to devices such as a magnetic sensor and a quantum memory. It is possible.

  FIG. 1 is a schematic diagram showing an atomic oscillator (quantum interference device) according to an embodiment of the present invention. FIG. 2 is a diagram for simply explaining the energy state of an alkali metal atom. FIG. 3 is a graph illustrating a relationship between a frequency difference between two lights emitted from the light source unit and an intensity of light detected by the light detection unit.

  The atomic oscillator 1 is an oscillator using the quantum interference effect, and includes a quantum interference unit 10 and a circuit unit 20 electrically connected to the quantum interference unit 10, as shown in FIG.

  The quantum interference unit 10 includes, for example, an atomic cell 2 (gas cell) in which an alkali metal atom such as rubidium atom or cesium atom is sealed, a light source unit 3 that irradiates the atomic cell 2 with the resonance light pair LL1 and the adjustment light LL2, It has a light detection unit 4 for detecting the resonance light pair LL1 and the adjustment light LL2 transmitted through the cell 2, and a coil 5 for applying a magnetic field to the atomic cell 2.

  The circuit section 20 includes a circuit section 6 (first circuit section), a circuit section 7 (third circuit section), and a circuit section 8 (second circuit section). The circuit unit 6 includes a detection circuit 61 (first detection unit), a modulation circuit 62, a low-frequency oscillator 63, and a drive circuit 64 (first drive circuit). The circuit unit 7 includes a detection circuit 71 (third detection unit), a voltage controlled crystal oscillator 72 (VCXO), a modulation circuit 73, a low frequency oscillator 74, and a phase synchronization circuit 75 (PLL: phase locked loop). The circuit unit 8 includes a detection circuit 81 (second detection unit), a modulation circuit 82, a low-frequency oscillator 83, and a drive circuit 84 (second drive circuit).

  In the atomic oscillator 1, the circuit section 6 stabilizes the center frequency of the resonance light pair LL1 at a predetermined frequency, and the circuit section 7 stabilizes the frequency difference between the resonance light pairs at the predetermined frequency difference. As a result, an electromagnetically induced transparency (EIT) phenomenon occurs in which two resonance lights having a specific frequency difference are transmitted without being absorbed by the alkali metal. Further, the circuit unit 7 stabilizes the output signal of the voltage controlled crystal oscillator 72 (VCXO) at a predetermined frequency using the steep EIT signal generated due to the EIT phenomenon and outputs it as a clock signal. .

  In particular, in the atomic oscillator 1, the circuit section 8 stabilizes the frequency of the adjustment light LL2 at a predetermined frequency. Here, the resonance light pair LL1 is composed of two resonance lights circularly polarized in the same direction, while the adjustment light LL2 is composed of resonance light circularly polarized in the opposite direction to the resonance light LL1. Thereby, the intensity of the EIT signal can be increased, and the oscillation characteristics of the atomic oscillator 1 can be improved.

Hereinafter, each part of the atomic oscillator 1 will be sequentially described.
(Quantum interference unit)
As described above, the quantum interference unit 10 includes, for example, an atomic cell 2 (gas cell) in which alkali metal atoms such as rubidium atoms and cesium atoms are sealed, and a light source that irradiates the atomic cell 2 with the resonance light pair LL1 and the adjustment light LL2. A unit 3, a light detection unit 4 for detecting the resonance light pair LL1 and the adjustment light LL2 transmitted through the atomic cell 2, and a coil 5 for applying a magnetic field to the atomic cell 2.

[Atom cell]
The atomic cell 2 is filled with an alkali metal (alkali metal atom) such as gaseous rubidium, cesium, and sodium. In addition, a rare gas such as argon or neon, or an inert gas such as nitrogen may be sealed as a buffer gas together with the gaseous alkali metal in the atomic cell 2 as necessary.

  More specifically, as shown in FIG. 1, the atomic cell 2 includes a body 21 having a through hole 211 and a pair of windows 22 joined to the body 21 so as to cover the through hole 211. 23. The body 21 and the pair of windows 22 and 23 define (configure) an internal space S in which gaseous alkali metal is sealed.

  The constituent material of the body portion 21 is not particularly limited, and examples thereof include a glass material, a quartz crystal, and a silicon material. On the other hand, the constituent materials of the windows 22 and 23 are not particularly limited as long as they have the above-described transmittance for the resonance light pair LL1 and the adjustment light LL2, respectively. No. Here, since the body 21 is made of silicon and the windows 22 and 23 are made of glass, the body 21 and the window 22 can be easily and hermetically joined by anodic bonding.

  As shown in FIG. 2, the alkali metal atoms sealed in such an atomic cell 2 are composed of two different ground levels (a first ground level and a second ground level) and an excited level. It has a three-level energy level. The first ground level is an energy level lower than the second ground level.

Here, the resonance light (first resonance light) having a frequency ω ₁ corresponding to the energy difference between the first ground level and the excitation level, and the energy difference between the second ground level and the excitation level resonance light having a corresponding frequency omega ₂ (second resonant light) alone by the light absorption by irradiating the alkali metal atoms occurs. On the other hand, when the first resonance light and the second resonance light (resonance light pair) are simultaneously irradiated, both of the first resonance light and the second resonance light are transmitted without being absorbed by the alkali metal atom (EIT). ) A phenomenon occurs. That is, in the EIT phenomenon, the alkali metal atoms are simultaneously irradiated with the first resonance light and the second resonance light, and the frequency difference (ω ₁ −) between the frequency ω ₁ of the first resonance light and the frequency ω ₂ of the second resonance light. ω ₂ ) coincides with the frequency ω ₀ corresponding to the energy difference ΔE between the first ground level and the second ground level. Therefore, as shown in FIG. 3, the light absorptivity (light transmittance) of the first resonance light and the second resonance light in the alkali metal atom changes according to the frequency difference (ω ₁ −ω ₂ ), and the frequency difference (ω ₁ −ω ₂ ) When (ω ₁ −ω ₂ ) coincides with the frequency ω ₀ , the EIT phenomenon occurs, and the intensity of the first resonance light and the second resonance light transmitted through the alkali metal atom sharply increases. Such a steep signal is called an EIT signal. This EIT signal has an eigenvalue determined by the type of the alkali metal atom. Therefore, by using such an EIT signal as a reference, a highly accurate oscillator can be configured.

  The atomic cell 2 has been described above. Such an atomic cell 2 is heated by a heater (not shown) driven based on a detection result of a temperature sensor (not shown) for detecting the temperature of the atomic cell 2. Thereby, the alkali metal in the atomic cell 2 can be maintained in a gaseous state having an appropriate concentration.

[Light emitting unit]
The light source unit 3 has a function of emitting the resonance light pair LL1 and the adjustment light LL2. The resonance light pair LL1 is composed of the above-described first resonance light (probe light) and second resonance light (coupling light) which are circularly polarized in the same direction. On the other hand, an EIT phenomenon occurs. On the other hand, the adjustment light LL2 is third resonance light that is circularly polarized in the opposite direction to the first resonance light and the second resonance light, and adjusts the magnetic quantum number of the alkali metal atom in the atomic cell 2. Here, “circularly polarized light” means that when focusing on either the electric field component or the magnetic field component of a light wave, the direction of the vibration rotates at the frequency of the light wave in a plane perpendicular to the light traveling direction. However, it is light whose amplitude is constant irrespective of its direction, in other words, light in which the vibration of an electric field (or magnetic field) draws a circle as it propagates. Note that the resonance light pair LL1 and the adjustment light LL2 will be described later in detail.

  As shown in FIG. 1, the light source unit 3 includes a first light source unit 31 that emits a resonance light pair LL1 (first light) and a second light source unit 32 that emits adjustment light LL2 (second light). Have.

  The first light source unit 31 includes a first light source 311 (first light emitting element), a 波長 wavelength plate 313, and an aperture member 34. On the other hand, the second light source section 32 includes a second light source 321, a 波長 wavelength plate 313, and a stop member 34. Here, the 波長 wavelength plate 313 and the aperture member 34 are provided in common with the first light source unit 31 described above. That is, it can be said that the １ ／ wavelength plate 313 and the aperture member 34 are provided in the first light source unit 31 and that the second light source unit 32 is provided.

  The first light source 311 and the second light source 321 are arranged on a substrate 33 such as a silicon substrate. The first light source 311 has a function of emitting light LL1a that includes linearly polarized first resonance light and second resonance light. On the other hand, the second light source 321 has a function of emitting light LL2a including third resonance light linearly polarized in a direction orthogonal to the direction of linearly polarized light LL1a from the first light source 311. Here, the lights LL1a and LL2a are emitted with a predetermined radiation angle. Thereby, it is possible to irradiate the atomic cell 2 in a state where the resonance light pair LL1 and the adjustment light LL2 are superimposed. Note that “linearly polarized light” is light in which the vibration surface of an electromagnetic wave (light) is within one plane, in other words, light in which the vibration direction of an electric field (or magnetic field) is constant.

  Each of the first light source 311 and the second light source 321 is, for example, but not limited to, a semiconductor laser such as an edge emitting laser or a vertical cavity surface emitting laser (VCSEL). In particular, since each of the first light source 311 and the second light source 321 is a surface emitting laser, the resonance light pair LL1 and the adjustment light LL2 having a desired frequency can be easily generated. In addition, the second light source 321 may be a light emitting element such as a light emitting diode (LED) and an organic electroluminescence (organic EL) element in addition to the semiconductor laser.

  Further, it is preferable that the output of the second light source 321 (the intensity of the light LL2a) is smaller than the output of the first light source 311 (the intensity of the light LL1a). As a result, an effect by the adjustment light as described later can be effectively generated.

  The 波長 wavelength plate 313 is a birefringent element that generates a phase difference π / 2 (90 °) between orthogonal polarization components of incident light. This quarter-wave plate 313 has a function of converting the light LL1a from the first light source 311 from linearly polarized light to circularly polarized (including elliptically polarized light) resonant light pair LL1. The quarter-wave plate 313 also has a function of converting the light LL2a from the second light source 321 from linearly polarized light to circularly polarized light (including elliptically polarized light) LL2. Here, the polarization direction of the linearly polarized light LL2a is different from the polarization direction of the linearly polarized light LL1a (the direction orthogonal to the polarization direction). Therefore, when the resonance light pair LL1 generated by the 波長 wavelength plate 313 is right circularly polarized light, the adjustment light LL2 generated by the quarter wavelength plate 313 is left circularly polarized light, while the resonance light pair LL1 is left polarized. In the case of circularly polarized light, the adjustment light LL2 is right circularly polarized light. By irradiating the atomic cell 2 with the resonance light pair LL1 and the adjustment light LL2 circularly polarized in the rotation directions opposite to each other from the same side, the rotation of the circularly polarized light of the adjustment light LL2 in the atom cell 2 The direction is opposite to the rotation direction of the circularly polarized light of the resonance light pair LL1.

  The aperture member 34 is arranged on the surface of the quarter-wave plate 313 opposite to the atomic cell 2. The aperture member 34 has an opening 341 for passing light in a partial region of the incident light, and has a function of adjusting the width (diameter) and shape of the light. Thereby, a part of the light LL1a from the first light source 311 passes through the opening 341 and thereby the width and the shape of the light LL1a are adjusted. Further, a part of the light LL2a from the second light source 321 passes through the opening 341 and thereby the width and the shape of the light LL2a are adjusted. Here, when viewed from the direction along the axis a that is the optical axis of the light source unit 3, the opening 341 is included in the area where the light LL1a and the light LL2a overlap on the surface along the diaphragm member 34. Is preferred. Thereby, the light LL1a and the light LL2a that have passed through the stop member 34 can be made to have the same passage area (matched or approximated area).

  The portion of the diaphragm member 34 except for the opening 341 has a light shielding property. The constituent material of the diaphragm member 34 is not particularly limited as long as the portion of the diaphragm member 34 except for the opening 341 can have light shielding properties. For example, a resin material, a metal material, or the like can be used. It is preferable that the portion other than the opening 341 of the aperture member 34 can prevent light reflection. Further, the method for forming the aperture member 34 is not particularly limited. In the case of the present embodiment, for example, the aperture member 34 can be formed on the 波長 wavelength plate 313 by using a known film forming method.

  Here, in the atomic cell 2, it is preferable that the passage area of the resonance light pair LL1 coincides with or is included in the passage area of the adjustment light LL2. In the present embodiment, in the atomic cell 2, the respective optical axes of the resonance light pair LL1 and the adjustment light LL2 are parallel to the axis a along the direction in which the windows 22 and 23 of the atomic cell 2 are aligned. ing. Thereby, the passage areas of the resonance light pair LL1 and the adjustment light LL2 that have passed through the stop member 34 can be made to coincide with each other. If the passage area of the resonance light pair LL1 can be matched or approximated with the passage area of the adjustment light LL2 in the atomic cell 2, the optical axes of the resonance light pair LL1 and the adjustment light LL2 are inclined with respect to the axis a. It may be.

  The light source unit 3 (the first light source unit 31 and the second light source unit 32) has been described above. Note that a lens may be arranged between the first light source 311 and the second light source 321 and the atomic cell 2. In this case, for example, the resonance light pair LL1 and the adjustment light LL2 in the atomic cell 2 can be parallel light. Further, a 波長 wavelength plate may be arranged between the first light source 311 and the second light source 321 and the 波長 wavelength plate 313. In this case, the first light source 311 and the second light source 321 may be installed in a posture rotated by 90 ° around the optical axis.

[Light detector]
The light detection unit 4 is disposed on the side opposite to the light source unit 3 with respect to the atomic cell 2. The light detection unit 4 has a function of detecting the intensity of the resonance light pair LL1 and the adjustment light LL2 transmitted through the atomic cell 2, and outputting a signal corresponding to the detected intensity.

  The light detection unit 4 is not particularly limited as long as it can detect the intensity of the resonance light pair LL1 and the adjustment light LL2. For example, a light detector (light receiving element) such as a photodiode can be used.

[coil]
The coil 5 has a function of applying a magnetic field to the alkali metal in the atomic cell 2 by energization. Thereby, the gap between a plurality of different energy levels in which the alkali metal atoms in the atomic cell 2 are degenerated can be expanded by Zeeman splitting, and the resolution can be improved. As a result, the accuracy of the oscillation frequency of the atomic oscillator 1 can be improved.

  Here, the magnetic field from the coil 5 is along the traveling direction of the resonance light pair LL1 and the adjustment light LL2 (substantially parallel) in the atomic cell 2. In addition, from the viewpoint of efficiently causing the resonance light pair and the adjustment light to act on the alkali metal in the atomic cell 2, the direction of the magnetic field from the coil 5 in the atomic cell 2 is in the traveling direction of the resonance light pair LL1. On the other hand, it is preferably from 0 ° to 30 °, more preferably from 0 ° to 20 °, and further preferably from 0 ° to 10 °.

  In the present embodiment, the coil 5 is a coil wound around the outer circumference of the atomic cell 2 so as to form a solenoid type. The coil 5 may be constituted by a pair of coils provided to face each other via the atomic cell 2 so as to form a Helmholtz type.

  Further, the magnetic field generated by the coil 5 is a constant magnetic field (DC magnetic field), but an AC magnetic field may be superimposed. The energization of the coil 5 is controlled by a magnetic field control unit (not shown) so that the magnetic field generated by the coil 5 becomes constant.

(Circuit section)
As described above, the circuit unit 20 illustrated in FIG. 1 includes the circuit unit 6 (first circuit unit), the circuit unit 7 (third circuit unit), and the circuit unit 8 (second circuit unit).

[First circuit unit]
The circuit unit 6 includes a detection circuit 61 (first detection unit), a modulation circuit 62, a low-frequency oscillator 63, and a drive circuit 64.

  The detection circuit 61 synchronizes the output signal of the light detection unit 4 using an oscillation signal (a signal of the first frequency) of the low frequency oscillator 63 that oscillates at a low frequency f1 (a first frequency) of about several Hz to several hundred Hz. Detect. The modulation circuit 62 modulates the output signal of the detection circuit 61 using the output signal (oscillation signal) of the low-frequency oscillator 63 as a modulation signal in order to enable synchronous detection by the detection circuit 61. Then, the output signal of the modulation circuit 62 is output to the drive circuit 64.

  The drive circuit 64 finely adjusts the bias current according to the output signal of the modulation circuit 62 and sets the bias current to be supplied to the first light source 311 (sets the center wavelength of the light emitted from the first light source 311). . That is, the center wavelength of light emitted from the first light source 311 is controlled (finely adjusted) by a feedback loop passing through the first light source 311, the atomic cell 2, the light detection unit 4, the detection circuit 61, the modulation circuit 62, and the drive circuit 64. You.

  Further, the drive circuit 64 superimposes a current of a modulation frequency (modulation current) output from a phase synchronization circuit 75 (PLL) described later on the bias current and supplies the bias current to the first light source 311. For example, although not shown, the drive circuit 64 includes a bias tee (high-frequency component) that superimposes the modulation current on the bias current and outputs the resultant to the first light source 311.

[Second circuit unit]
The circuit unit 8 includes a detection circuit 81 (second detection unit), a modulation circuit 82, a low-frequency oscillator 83, and a drive circuit 84.

  The detection circuit 81 synchronizes the output signal of the light detection unit 4 using an oscillation signal (a signal of the second frequency) of the low frequency oscillator 83 that oscillates at a low frequency f2 (a second frequency) of about several Hz to several hundred Hz. Detect. The modulation circuit 82 modulates the output signal of the detection circuit 81 using the output signal (oscillation signal) of the low-frequency oscillator 83 as a modulation signal in order to enable detection by the detection circuit 81. Then, the output signal of the modulation circuit 82 is output to the drive circuit 84.

  The drive circuit 84 finely adjusts the bias current according to the output signal of the modulation circuit 82 and sets the bias current to be supplied to the second light source 321 (sets the wavelength of the light emitted from the second light source 321). That is, the wavelength (center wavelength) of the light emitted from the second light source 321 is controlled (fine) by a feedback loop passing through the second light source 321, the atomic cell 2, the light detection unit 4, the detection circuit 81, the modulation circuit 82, and the drive circuit 84. Adjusted).

[Third circuit unit]
The circuit unit 7 includes a detection circuit 71 (third detection unit), a voltage controlled crystal oscillator (VCXO: Voltage Controlled Crystal Oscillators) 72, a modulation circuit 73, a low-frequency oscillator 74, and a phase synchronization circuit 75 (PLL: phase locked loop).

  The detection circuit 71 synchronizes the output signal of the light detection unit 4 using an oscillation signal (a signal of the third frequency) of the low frequency oscillator 74 that oscillates at a low frequency f3 (a third frequency) of about several Hz to several hundred Hz. Detect. The oscillation frequency of the voltage-controlled crystal oscillator (VCXO) 72 is finely adjusted according to the magnitude of the output signal of the detection circuit 71. The voltage controlled crystal oscillator (VCXO) 72 oscillates at a low frequency of, for example, several tens Hz to several hundreds Hz.

  The modulation circuit 73 modulates the output signal of the voltage-controlled crystal oscillator (VCXO) 72 using the oscillation signal of the low-frequency oscillator 74 as a modulation signal in order to enable detection by the detection circuit 71.

  The phase synchronization circuit 75 converts the output signal of the modulation circuit 73 at a constant frequency conversion rate (multiplication ratio) and outputs it. Thereby, the phase locked loop 75 multiplies the output of the modulation circuit 73 to generate a modulation current. For example, the phase locked loop 75 determines that the frequency difference corresponding to the energy difference between the two ground levels of the alkali metal atom having the magnetic quantum number m = 0 enclosed in the atomic cell 2 is ２ (9 in the case of cesium atom). (1926 GHz / 2 = 4.5963 GHz). Note that the phase synchronization circuit 75 converts the output signal of the modulation circuit 73 into a frequency difference (cesium atom) corresponding to the energy difference between two ground levels of the alkali metal atom having the magnetic quantum number m = 0 sealed in the atomic cell 2. May be converted into a signal having a frequency equal to 9.1926 GHz.

  Then, the output signal of the phase synchronization circuit 75 is input to the drive circuit 64 as a modulation current. When the light emitted from the first light source 311 is frequency-modulated by the modulation current, the light having a center frequency (center wavelength) corresponding to the bias current and sideband light on both sides thereof are respectively provided by the frequency of the modulation current. Light of two shifted frequencies is generated (see FIG. 7).

  The first light source 311 emits light through a feedback loop passing through the first light source 311, the atomic cell 2, the light detection unit 4, the detection circuit 71, the voltage controlled crystal oscillator 74, the modulation circuit 73, the phase synchronization circuit 75, and the drive circuit 64. The frequency difference of the sand band light is controlled (finely adjusted) so that the EIT phenomenon occurs in the alkali metal atom. At this time, the output signal of the voltage controlled crystal oscillator 74 is stabilized at a predetermined frequency. The output signal of the voltage controlled crystal oscillator 74 is output to the outside. At this time, the output signal of the voltage controlled crystal oscillator 74 is frequency-converted to a desired frequency at a predetermined frequency conversion rate by a frequency conversion circuit (not shown) such as a DDS (Direct Digital Synthesizer) as necessary. You may.

  The circuit unit 20 described above is provided, for example, on an IC chip mounted on a substrate.

  The configuration of the atomic oscillator 1 has been described above. In such an atomic oscillator 1, as described above, not only the resonance light pair LL <b> 1 causing the EIT phenomenon for the alkali metal atoms in the atomic cell 2, but also the magnetic quantum number of the alkali metal atoms in the atomic cell 2. The adjustment light LL2 to be adjusted is used. Hereinafter, the resonance light pair LL1 and the adjustment light LL2 will be described in detail.

(Detailed description of resonance light pair and adjustment light)
FIG. 4 is a diagram illustrating an example of the relationship between the energy state of a cesium atom, a resonance light pair (first resonance light, second resonance light), and adjustment light (third resonance light). 5A and 5B are diagrams showing the distribution of the magnetic quantum number of sodium atoms. FIG. 5A is a diagram showing the distribution when σ ₊ circularly polarized resonance light is irradiated, and FIG. sigma _- is a diagram showing the distribution of when irradiated with circularly polarized light of the resonant light.

For example, when cesium atoms are sealed in the atomic cell 2, as shown in FIG. 4, D1 which is σ ₊ polarized light (left circularly polarized light) as the first resonance light and the second resonance light (resonance light pair). A D2 line that is σ _- polarized (right circularly polarized light) is used as the third resonance light (adjustment light). Note that the first resonance light and the second resonance light may be σ _- polarized light, the third resonance light may be σ ₊ polarization, and the first resonance light and the second resonance light may be D2 line and the third resonance light. May be the D1 line.

Cesium atom is a kind of alkali metal atoms _has a ground level of _{6S 1/2,} and two excited levels of _{6P 1/2} and _{6P 3/2,} the. In addition, each level of 6S _1/2 , 6P _1/2 , and 6P _3/2 has a fine structure split into a plurality of energy levels. Specifically, the 6S _1/2 level has two ground levels of F = 3, 4, the 6P _1/2 level has two excited levels of F ′ = 3, 4, The 6P _3/2 level has four excitation levels of F ″ = 2, 3, 4, 5.

The cesium atom in the first ground level of F = 3 of 6S _1/2 transitions to any of the excitation levels of F ″ = 2, 3, or 4 of 6P _3/2 by absorbing the D2 line. But cannot transition to an excitation level of F ″ = 5. The cesium atom in the second ground level of F = 4 of 6S _1/2 transitions to the excitation level of F ″ = 3, 4, or 5 of 6P _3/2 by absorbing the D2 line. But cannot transition to the excitation level of F ″ = 2. These are based on a transition selection rule when an electric dipole transition is assumed. Conversely, a cesium atom at any of the excitation levels of F ″ = 3, 4 of 6P _3/2 emits a D2 line, and the ground level of F = 3 or F = 4 of 6S _1/2 ( Either the original ground level or the other ground level). Such 6S _1/2 F = 3, 4 ground levels and 6P _3/2 F ″ = A three-level consisting of any one of the three or four excitation levels is called a Λ-type three-level because a ２-type transition by absorption and emission of the D2 line is possible. Similarly, the three levels including the two ground levels of F = 3 and 4 of 6S _1/2 and the excitation level of F ′ = 3 and 4 of 6P _1/2 are also the absorption levels of the D1 line. Since Λ-type transition by light emission is possible, Λ-type three levels are formed.

On the other hand, the cesium atom at the excitation level of F ″ = 2 of 6P _3/2 emits the D2 line and always becomes the ground level of F = 3 of 6S _1/2 (original ground level). Similarly, the cesium atom at the excitation level of F ″ = 5 of 6P _3/2 emits the D2 line and the ground level of F = 4 of 6S _1/2 (the original ground level) ). Therefore, the three levels consisting of two ground levels of F = 3 and 4 of 6S _1/2 and an excitation level of F ″ = 2 or F ″ = 5 of 6P _3/2 are absorbed and emitted by the D2 line. Does not form a Λ-type three level.

Such a cesium atom has a D1 line wavelength in a vacuum of 894.593 nm, a D2 line wavelength in a vacuum of 852.347 nm, and a hyperfine splitting frequency of 6S _1/2 (energy difference ΔE). corresponding to frequency ω ₀₎ in is 9.1926GHz.

Note that an alkali metal atom other than a cesium atom also has two ground levels and an excited level that form a Λ-type three level. Here, the sodium atom has a D1 line wavelength in a vacuum of 589.756 nm, a D2 line wavelength in a vacuum of 589.158 nm, and a hyperfine splitting frequency (ω ₀ ) of 3S _1/2. Is 1.7716 GHz. The rubidium ( ⁸⁵ Rb) atom has a D1 line wavelength in a vacuum of 794.979 nm, a D2 line wavelength in a vacuum of 780.241 nm, and a hyperfine splitting frequency of 5S _1/2 ( ω ₀ ) is 3.0357 GHz. Furthermore, rubidium ⁽⁸⁷ Rb) atom is the wavelength of the D1 line is 794.979nm in vacuum, the wavelength of the D2 line is 780.241nm in _{vacuum, 5S 1/2} of hyperfine splitting frequency ( ω ₀ ) is 6.8346 GHz.

For example, as shown in FIG. 5, a sodium atom, which is a kind of alkali metal atom, has two ground levels and an excited level that form a Λ-type three level, and has a 3S _1/2 F = 1. The first ground level has three magnetic quantum numbers of m _F1 = −1, 0, and 1, and the second ground level of F = 2 of 3S _1/2 is m _F2 = −2, −1. has the number five magnetic quantum of 0, 1, _2, F a _{3P 1/2} '= 2 excited state density, m _F' = -2, five magnetic -1,0,1,2 It has a quantum number.

When a sodium atom at the ground level of F = 1 or F = 2 is irradiated with a σ ₊ circularly-polarized resonance light pair, as shown in FIG. Is excited to an excited level. At this time, the distribution of the sodium atom at the ground level of F = 1 or F = 2 changes in the direction with the larger magnetic quantum number.

On the other hand, when a sodium atom at the ground level of F = 1 or F = 2 is irradiated with a σ _- circularly-polarized resonance light pair, the magnetic quantum number is reduced by one as shown in FIG. It is excited to an excited level by a rule. At this time, the distribution of the sodium atom at the ground level of F = 1 or F = 2 changes to the one with the smaller magnetic quantum number.

  In FIG. 5, for convenience of explanation, the distribution of the magnetic quantum number is shown by taking a sodium atom having a simple structure as an example. However, in other alkali metal atoms, the ground level and the excitation level are each 2F + 1. The number of magnetic quantum numbers (magnetic sub-levels), and the distribution of magnetic quantum numbers changes according to the above-described selection rule.

  As described above, when irradiating the alkali metal in the atomic cell 2 with the resonance light pair LL1 and the adjustment light LL2 from the same direction, one of the resonance light pair LL1 and the adjustment light LL2 is right-circularly polarized light, and the other is the other. By using left-handed circularly polarized light, the bias of the magnetic quantum number of the alkali metal can be reduced.

  Here, since the resonance light pair LL1 is the D1 line and the adjustment light LL2 is the D2 line, the EIT phenomenon caused by the adjustment light LL2 can be reduced, and the intensity of the EIT signal can be efficiently improved.

  Here, as described above, the resonance light pair LL1 has the center frequency (center wavelength) of the light from the first light source 311 controlled by the circuit unit 6 and the frequency between the sideband lights from the first light source 311. The difference is generated by being controlled by the circuit unit 7. The adjustment light LL <b> 2 is generated by controlling the frequency (wavelength) of the light from the second light source 321 by the circuit unit 8.

  When the resonance light pair LL1 and the adjustment light LL2 are generated as described above, the frequencies f1, f2, and f3 that are the oscillation frequencies of the low-frequency oscillators 63, 74, and 83 are different from each other in the circuit units 6, 7, and 8. As a result, the detection circuits 61, 71, and 81 detect the center wavelength (center frequency) of the resonance light pair LL1, the wavelength (frequency) of the adjustment light LL2, and the resonance light pair LL1 (from the output signal of one photodetector 4). Signals relating to the wavelength difference (frequency difference) between the first resonance light and the second resonance light) can be detected separately. Hereinafter, these synchronous detections will be described in detail.

(Detection of detection circuit)
FIG. 6 is a diagram illustrating a D1 line absorption spectrum of an alkali metal atom (cesium atom). FIG. 7 is a diagram illustrating the relationship between the D1 line absorption spectrum of an alkali metal atom (cesium atom) and the frequency of a resonance light pair. The “detuning frequency” on the horizontal axis in FIG. 6 is a frequency based on a peak D described later. In FIG. 7, the energy level when the alkali metal atom is a cesium atom and the frequency components of the light from the first light source 311 corresponding to this energy level (frequency components of + 3rd order or higher and −3rd or lower order) Are omitted).

  The output signal of the light detection unit 4 includes, for example, an absorption spectrum component of a D1 line of an alkali metal atom as shown in FIG. 6 in synchronization with the frequency f1 (first frequency). Then, in the circuit section 6, the detection circuit 61 detects the output signal of the light detection section 4 using the signal of the frequency f1 from the low frequency oscillator 63 and outputs the first signal.

Here, such absorption spectrum has seven peaks A~G shifted by frequency ω _0/2. Among them, the peak D at the center has the highest peak intensity. As shown in FIG. 7, the peak D has a frequency of the + 1st-order sideband light corresponding to the energy difference between the first ground level and the excitation level, and has a frequency of the -1st-order sideband light. This corresponds to a state in which the frequency corresponds to the energy difference between the second ground level and the excitation level. That is, the peak D corresponds to a state in which the ± 1st-order sideband light forms a resonance light pair. The peak C is a state in which the + 2nd-order sideband light and the 0th-order light are a resonance light pair, and the peak B is a + 3rd-order sideband light and a + 1st-order sideband light are a resonance light pair. The state, peak A, is a state in which the + 4th-order sideband light and the + 2nd-order sideband light are a resonance light pair, and the peak E is a -2nd-order sideband light and 0th-order light are a resonance light pair. , The peak F is a state in which the -3 order sideband light and the -1 order sideband light are a resonance light pair, and the peak G is a -4 order sideband light and a -2nd order sideband light. Corresponds to a state in which a resonance light pair is formed.

  Then, the circuit unit 6 detects any one of the peaks A to G and performs control so as to stabilize the detection state. That is, in the circuit section 6, the bias current when any one of the peaks A to G is set in the drive circuit 64.

  In particular, it is preferable that the circuit section 6 detects the peak D and performs control so as to stabilize the detection state. Thereby, the center wavelength of the light from the first light source 311 can be most stabilized at a desired wavelength.

  FIG. 8 is a diagram illustrating a D2-line absorption spectrum of an alkali metal atom (cesium atom). FIG. 9 is a diagram illustrating the relationship between the D2 line absorption spectrum of an alkali metal atom (cesium atom) and the frequency of the adjustment light. The “detuning frequency” on the horizontal axis in FIG. 8 is a frequency based on an intermediate value between a peak H and a peak I described later. FIG. 9 shows the relationship between the energy level when the alkali metal atom is a cesium atom and the frequency of light from the second light source 321 corresponding to this energy level.

  The output signal of the light detection unit 4 includes, for example, a component of an absorption spectrum of a D2 line of an alkali metal atom as illustrated in FIG. 8 in synchronization with the frequency f2 (second frequency). Then, in the circuit section 8, the detection circuit 81 detects the output signal of the light detection section 4 using the signal of the frequency f2 from the low frequency oscillator 83, and outputs a second signal.

Here, such absorption spectrum has a frequency omega ₀ shifted two peaks H, a I. Among them, the peak H on the lower frequency side has a higher peak intensity than the peak I on the higher frequency side. This peak H corresponds to the case where the frequency of the light from the second light source 321 reaches a frequency corresponding to the energy difference between the second ground level and the excitation level, as shown in FIG. Note that the peak I corresponds to a state in which the frequency of the light of the second light source 321 becomes a frequency corresponding to the energy difference between the first ground level and the excitation level.

  Then, the circuit unit 8 detects one of the peaks H and I, and performs control so as to stabilize the detection state. That is, the circuit section 8 sets the bias current at the time of one of the peaks H and I in the drive circuit 84.

  In particular, it is preferable that the circuit unit 8 detects the peak H and performs control so as to stabilize the detection state. Thereby, the wavelength of the light from the second light source 321 can be most stabilized at a desired wavelength.

  FIG. 10 is a diagram illustrating an EIT spectrum of an alkali metal atom (cesium atom).

  The output signal of the light detection unit 4 includes, for example, a component of an EIT spectrum (spectrum due to the EIT phenomenon) of an alkali metal atom as shown in FIG. 10 in synchronization with the frequency f3 (third frequency). Then, the circuit unit 7 detects the output signal of the light detection unit 4 using the signal of the frequency f3 from the low frequency oscillator 74 and outputs a third signal.

Here, the EIT spectrum has one peak that is an EIT signal. EIT signal, as described above, occurs when the frequency difference between the two sidebands light from the first light source 311 is omega _0.

  For this reason, the circuit unit 8 detects the peak of the EIT spectrum and performs control so as to stabilize the detection state. That is, the circuit section 8 causes the phase synchronization circuit 75 to generate a modulation current when the EIT spectrum reaches a peak.

  As described above, the D1 line absorption spectrum, the D2 line absorption spectrum, and the EIT spectrum of the alkali metal atom are detected separately from the output signal of the light detection unit 4.

  As described above, the circuit unit 6 generates the bias current input to the first light source 311 using the oscillation signal of the frequency f1 output from the low-frequency oscillator 63, and converts the output signal of the light detection unit 4 Perform synchronous detection. Further, the circuit unit 7 generates a modulation current input to the first light source 311 using the oscillation signal of the frequency f3 output from the low-frequency oscillator 74, and synchronously detects the output signal of the light detection unit 4. . Further, the circuit unit 8 generates a bias current input to the second light source 321 using the oscillation signal of the frequency f2 output from the low-frequency oscillator 83, and synchronously detects the output signal of the light detection unit 4. .

  Here, in the output signal of the light detection unit 4, the D1 line absorption spectrum of the alkali metal atom appears in synchronization with the frequency f1, the D2 line absorption spectrum appears in synchronization with the frequency f2, and the EIT spectrum appears in the frequency f3. Appears in synchronization with. Therefore, in order to detect the D1 line absorption spectrum, the D2 line absorption spectrum and the EIT spectrum of the alkali metal atom from the output signal of the photodetecting section 4, the frequencies f1, f2 and f3 must be different from each other. Is required. That is, the relationship of f1 <f2 <f3, the relationship of f1 <f3 <f2, the relationship of f2 <f1 <f3, the relationship of f2 <f3 <f1, the relationship of f3 <f1 <f2, and the relationship of f3 <f2 <f1 One of these needs to be met.

  At this time, it is preferable that the frequencies f1, f2, and f3 do not have an integral multiple of each other, or that the frequencies f1, f2, and f3 have sufficiently different frequencies even if they have an integral multiple of each other.

  More specifically, when the larger one of any two of the frequencies f1, f2, and f3 is A and the smaller one is B, A / B is preferably 5 or more and 100 or less, More preferably, it is 7 or more and 50 or less. Thus, even if the frequencies f1, f2, and f3 are in integral multiples of each other, the D1 line absorption spectrum, the D2 line absorption spectrum, and the EIT spectrum of the alkali metal atom can be distinguished and detected with high accuracy. On the other hand, if A / B is too small, the frequencies f1, f2, and f3 are integral multiples of each other, and the D1 line absorption spectrum, D2 line absorption spectrum, and EIT spectrum of the alkali metal atom are distinguished from each other. It is difficult to detect with accuracy. On the other hand, if the A / B ratio is too large, the configurations of the circuit units 6, 7, and 8 necessary for distinguishing and detecting the D1 line absorption spectrum, D2 line absorption spectrum, and EIT spectrum of the alkali metal atom become complicated.

  Further, it is preferable that the frequency f3 is higher than both the frequency f1 and the frequency f2. The line width of the EIT signal of the alkali metal atom is smaller than the line width of the absorption spectrum of the alkali metal atom. Therefore, by making the frequency f3 higher than the frequencies f1 and f2, the signal relating to the frequency difference between the resonance light pair LL1 and the signal relating to the center wavelength of the resonance light pair LL1 and the signal relating to the wavelength of the adjustment light LL2 can be easily detected in the detection circuit 71. Detection can be performed separately.

  In the atomic oscillator 1 described above, in addition to the resonance light pair LL1 circularly polarized in the same direction as each other, the adjustment light circularly polarized in the rotational direction opposite to the resonance light pair LL1 in the atomic cell 2 in the atomic cell 2. By irradiating the alkali metal with LL2, the bias of the distribution of magnetic quantum numbers due to the resonance light pair LL1 is offset or reduced by the adjustment light LL2, and the bias of the distribution of magnetic quantum numbers of the alkali metal can be reduced. Therefore, the number of alkali metal atoms having a desired magnetic quantum number contributing to the EIT is increased, and as a result, the effect of improving the intensity of the EIT signal is significantly exhibited by using the circularly polarized resonance light pair LL1. Therefore, the intensity of the EIT signal can be effectively improved.

  Here, since the frequencies f1, f2, and f3 are different from each other, the center wavelength (center frequency) of the resonance light pair LL1, the wavelength (frequency) of the adjustment light LL2, and the wavelength difference (frequency difference) between the resonance light pair LL1 are determined. By changing the frequency in synchronization with the frequency, the center wavelength (center frequency) of the resonance light pair LL1 and the wavelength (adjustment light LL2) of the resonance light pair LL1 are obtained from the output signals of one light detection unit 4 using the detection circuits 61, 71, 81. The signals relating to the frequency (frequency) and the wavelength difference (frequency difference) between the resonance light pair LL1 can be detected separately. Therefore, it is possible to stabilize the respective wavelengths and oscillation frequencies of the resonance light pair LL1 and the adjustment light LL2 using the signals of the detection circuits 61, 71, 81.

  More specifically, as described above, the drive circuit 64 drives the first light source 311 using the output signals (the first signal and the third signal) of the detection circuits 61 and 71. Thus, the drive circuit 64 can drive the first light source 311 by superimposing the bias current based on the first signal and the modulation current based on the third signal and inputting the superimposed current to the first light source 311. The center wavelength of the resonance light pair LL1 can be stabilized by the bias current based on the first signal, and the frequency difference between the resonance light pair LL1 can be stabilized by the modulation current based on the third signal.

  Further, as described above, the drive circuit 84 drives the second light source 321 using the output signal (second signal) of the detection circuit 81. Accordingly, the drive circuit 84 can drive the second light source 321 by inputting the bias current based on the second signal to the second light source 321. Then, the wavelength of the adjustment light LL2 can be stabilized by the bias current based on the second signal.

  Further, as described above, the voltage-controlled crystal oscillator 72 outputs a clock signal using the output signal (third signal) of the detection circuit 71. Thus, the voltage-controlled crystal oscillator 72 can output a clock signal having a frequency based on the third signal.

2. Electronic Equipment The atomic oscillator as described above can be incorporated in various electronic equipment.

Hereinafter, the electronic device of the present invention will be described.
FIG. 11 is a diagram showing a schematic configuration when the atomic oscillator of the present invention is used in a positioning system using GPS satellites.

  The positioning system 100 shown in FIG. 11 includes a GPS satellite 200, a base station device 300, and a GPS receiving device 400.

The GPS satellite 200 transmits positioning information (GPS signal).
The base station device 300 receives, for example, a receiving device 302 that receives positioning information from the GPS satellite 200 with high accuracy via an antenna 301 installed at an electronic reference point (a GPS continuous observation station), and the receiving device 302 receives the positioning information. A transmission device 304 for transmitting positioning information via the antenna 303.

  Here, the receiving device 302 is an electronic device including the above-described atomic oscillator 1 of the present invention as its reference frequency oscillation source. Such a receiving device 302 has excellent reliability. The positioning information received by the receiving device 302 is transmitted by the transmitting device 304 in real time.

  The GPS receiver 400 includes a satellite receiver 402 that receives positioning information from the GPS satellite 200 via an antenna 401, and a base station receiver 404 that receives positioning information from the base station 300 via an antenna 403. Prepare.

3. Moving Object FIG. 12 is a diagram illustrating an example of the moving object of the present invention.

  In this figure, a moving body 1500 has a vehicle body 1501 and four wheels 1502, and is configured to rotate the wheels 1502 by a power source (engine) (not shown) provided on the vehicle body 1501. The atomic oscillator 1 is built in such a moving object 1500.

  Note that the electronic device of the present invention is not limited to the above-described devices. For example, a smartphone, a tablet terminal, a clock, a mobile phone, a digital still camera, an inkjet discharge device (eg, an inkjet printer), a personal computer (mobile personal computer) , Laptop personal computer), TV, video camera, video tape recorder, car navigation system, pager, electronic organizer (including communication function), electronic dictionary, calculator, electronic game machine, word processor, workstation, videophone, Security TV monitor, electronic binoculars, POS terminal, medical equipment (for example, electronic thermometer, sphygmomanometer, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish finder, various measuring devices, instruments ( An example If, gages for vehicles, aircraft, and ships), a flight simulator, terrestrial digital broadcasting, cellular base stations, can be applied to the GPS module or the like.

  As described above, the quantum interference device, the atomic oscillator, the electronic device, and the moving object of the present invention have been described based on the illustrated embodiments, but the present invention is not limited to these.

  Further, the configuration of each unit of the present invention can be replaced with any configuration that exhibits the same function as the above-described embodiment, and any configuration can be added. In addition, the present invention may be configured to combine arbitrary configurations of the embodiments described above.

DESCRIPTION OF SYMBOLS 1 ... Atomic oscillator, 2 ... Atomic cell, 3 ... Light source part, 4 ... Light detection part, 5 ... Coil, 6 ... Circuit part, 7 ... Circuit part, 8 ... Circuit part, 10 ... Quantum interference unit, 20 ... Circuit part , 21 ... body part, 22 ... window part, 23 ... window part, 31 ... first light source part, 32 ... second light source part, 33 ... substrate, 34 ... diaphragm member, 61 ... detection circuit (first detection part), 62 modulation circuit, 63 low frequency oscillator, 64 drive circuit (first drive circuit), 71 detection circuit (third detection unit), 72 voltage controlled crystal oscillator (oscillator), 73 modulation circuit, 74 ... Low frequency oscillator, 75 ... Phase synchronization circuit, 81 ... Detection circuit (second detection unit), 82 ... Modulation circuit, 83 ... Low frequency oscillator, 84 ... Drive circuit (second drive circuit), 100 ... Positioning system, 200 ... GPS satellites, 211 ... through-holes, 300 ... base station devices, 301 ... antennas, 302 Receiving device, 303: Antenna, 304: Transmitting device, 311: First light source, 313: 1/4 wavelength plate, 321: Second light source, 341: Aperture, 400: GPS receiving device, 401: Antenna, 402: Satellite reception Unit, 403 antenna, 404 base station receiver, 1500 mobile unit, 1501 vehicle body, 1502 wheels, A peak, a axis, B peak, C peak, D peak, E peak, F: peak, f1: frequency, f2: frequency, f3: frequency, G: peak, H: peak, I: peak, LL1: resonance light pair, LL1a: light, LL2: adjustment light, LL2a: light, S: inside Space, ΔE: energy difference, ω ₀ : frequency, ω ₁ : frequency, ω ₂ : frequency

Claims (10)

An atomic cell having an internal space in which alkali metal atoms are enclosed,
A first light source unit that emits a resonance light pair that circularly polarizes in the same direction and excites the alkali metal atom,
A second light source that emits adjustment light that excites the alkali metal atom by circularly polarizing in the opposite direction to the resonance light pair in the internal space,
A light detection unit that detects the resonance light pair and the adjustment light that have passed through the internal space, and outputs a signal corresponding to the detected intensity.
A first detection unit that detects an output signal of the light detection unit and outputs a first signal using a signal of a first frequency;
A second detection unit that detects an output signal of the light detection unit and outputs a second signal by using a signal having a second frequency different from the first frequency;
A third detection unit that detects an output signal of the light detection unit and outputs a third signal by using a signal having a third frequency different from the first frequency and the second frequency. Quantum interference device.   2. The quantum interference device according to claim 1, further comprising: a first drive circuit that drives the first light source unit using the first signal and the third signal. 3.   The quantum interference device according to claim 2, further comprising a second driving circuit that drives the second light source unit using the second signal.   The quantum interference device according to claim 2, further comprising an oscillator that outputs a clock signal using the third signal.   The quantum interference device according to claim 2, wherein the third frequency is higher than the first frequency and the second frequency.   The quantum interference device according to claim 1, wherein the resonance light pair is a D1 line, and the adjustment light is a D2 line.   The quantum interference device according to claim 1, wherein each of the first light source unit and the second light source unit has a surface emitting laser.   An atomic oscillator comprising the quantum interference device according to any one of claims 1 to 7.   An electronic apparatus comprising the quantum interference device according to claim 1.   A moving object comprising the quantum interference device according to claim 1.

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