Phase difference measurement method, atom wave interferometer, angular velocity measurement method, and atom wave interferometer type gyroscope

Abstract

To further improve a phase signal extraction method of an atom wave interferometer although a phase signal extraction of atom interference waves by lock-in detection is an excellent measurement method.SOLUTION: A phase difference measurement method uses an atom wave interferometer that separates atom waves by first Raman beams, reflects them by second Raman beams, and separates them again by third Raman beams for interference. The phase of atom waves is modulated by applying an offset phase, and a vibration phase of amplitude β and an angular frequency ω to second Raman beams. An intensity signal I of atom interference waves is measured by an atom number measuring instrument. An observation phase difference Φ is calculated from the ω constituent, 2ω constituent, and amplitude β of the intensity signal I. A value obtained by subtracting an offset phase from the observation phase difference Φ is calculated as a measurement phase difference. An offset phase is subjected to feedback control to be cosΦ=-1.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The disclosed technology relates to a Mach-Zehnder atomic wave interferometer that uses atomic beams, and a gyroscope that applies it. [Background technology]

[0002] [Wave interference] Wave interference will be explained using Figure 1. Figure 1(a) shows how two waves with aligned crests and troughs reinforce each other when they are superimposed, while Figure 1(b) shows how two waves with opposing crests and troughs cancel each other out when they are superimposed. In this way, when the timing (=phase) of the waves is out of sync, they reinforce or cancel each other out. This is called "wave interference." A device that can precisely measure the phase difference based on the magnitude of the overlapping waves is called an interferometer.

[0003] [Laser interferometer gyroscope] A laser interferometer gyroscope will be explained using Figure 2. A gyroscope is a device that measures angular velocity and can detect the rotation of an interferometer within the xy plane in Figure 2. Suppose the output of a laser light source is given by equation (1).

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[0004] [Sagnac effect] Consider rotating the gyroscope in the plane of the optical path (in the xy plane) with the lengths of paths 1 and 2 equal. If the wavelength of light is λ, the speed is c, the area of the interferometer is A, and the angular velocity of the rotational motion is Ω, the phase difference Δφ observed by the interferometer is given by the following equation (Non-Patent Document 1):

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[0005] [Atomic wave] It is well known that sound and light exhibit wave properties, but according to quantum mechanics, atoms also exhibit wave properties. Let λ be the wavelength of the matter wave, λ M If we replace c with the atomic velocity v, then equation (7) also holds for atomic waves. Now, looking at equation (7), we can see that the smaller the value of λ×c, the higher the resolution of the angular velocity Ω. For example, if the wavelength of light is λ=500 nm (green light), then the speed of light c=3×10 8 Since it is m / s,

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[0006] [Atomic wave interferometer] By utilizing the atomic recoil caused by Raman scattering, it is possible to construct a Mach-Zehnder interferometer using atomic waves (Non-Patent Document 1).

[0007] <Raman scattering> Raman scattering is the inelastic collision of photons with atoms. It will be explained using Figure 3. Figure 3(a) shows the process in which an atom absorbs a photon of frequency ω1 and emits a photon of frequency ω2 (ω1>ω2). As a result of scattering, the atom gains momentum of (h / 2π)(k1+k2)=(h / 2πc)(ω1+ω2). Note that,

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[0008] Hereafter, the quantum mechanical state of an atom generated by an atomic beam source is represented as |g>, and the quantum mechanical state of an atom excited by Raman scattering and acquiring momentum (h / 2π)(k1+k2) is represented as |e>. The transition probability from |g> to |e> or from |e> to |g> can be adjusted by the interaction time between the Raman beam and the atom (Non-Patent Document 1).

[0009] <Mach-Zehnder interferometer> The Raman scattering described above is used to construct a Mach-Zehnder interferometer. This will be explained using Figure 4. Three Raman beams are arranged between the atomic beam source 41 and the interference wave detector 42 . Assume that an atomic wave in state |g> with momentum Mv0 in the x direction is supplied from the atomic beam source 41. Each Raman beam is formed by opposing laser light of frequency ω1 and laser light of frequency ω2. The first Raman beam 43 "partially" transitions the atomic wave in state |g> to state |e>. The atomic wave in state |e> gains momentum (h / 2π)(k1+k2) in the y direction and moves in the P→Q direction. The atomic wave that remains in state |g> does not change momentum and therefore moves in the P→R direction. In other words, the first Raman beam functions as an atomic wave splitter.

[0010] The second Raman beam 44 causes the atomic wave in the state |e> to transition "completely" to the state |g>, and also causes the atomic wave in the state |g> to transition "completely" to the state |e>. The atomic wave that has transitioned to state |g> loses momentum (h / 2π)(k1+k2) in the y direction and travels in the Q→S direction. The atomic wave that has transitioned to state |e> gains momentum (h / 2π)(k1+k2) in the y direction and travels in the R→S direction. In other words, the second Raman beam functions as a mirror for the atomic wave.

[0011] The third Raman beam 45, like the first Raman beam, "partially" transitions the atomic wave in the state |g> to the state |e>. It also "partially" transitions the atomic wave in the state |e> to the state |g>. The atomic wave in state |g> that has progressed from Q to S partially progresses from S to T, and the atomic wave in state |e> that has progressed from R to S partially transitions to state |g> and progresses from S to T, and the overlapping results are detected by the interference wave detector 42.

[0012] Now, when the phases acquired by the atomic wave during the propagation of PQS and PRS are φ1 and φ2, the state of the atomic wave following PQST is

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[0013] [Conventional phase signal readout / lock-in detection] I T If we can measure the phase difference between the atomic waves, we can solve equation (13) for φ1-φ2. However, I T The amount of change in is generally buried in noise, making it difficult to read directly.

[0014] In Raman scattering, the phase of the scattered atomic wave can be controlled by the phase of the Raman beam. Taking advantage of this, a technique is known for measuring the intensity of the interference wave with high sensitivity by lock-in detection (Non-Patent Document 1). This will be explained using Figure 5. When the atomic wave on path 1 is scattered by the second Raman beam, the phase is θ(t), and the atomic wave on path 2 is -θ(t). The state of the atomic wave that has traveled the PQST is as follows:

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[0015] θ(t)=ω sThe phase of the atomic wave is swept by giving t. The atomic wave intensity I observed at position T is S teeth,

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[0016] Lock-in detection allows the I Lock However, as can be seen from equation (18), I Lock Since depends on the magnitude of I0, even if phase sweep and lock-in detection of the atomic wave are used, the effects of intensity fluctuations and quantum fluctuations of the atomic wave cannot be avoided. [Prior art documents] [Non-patent literature]

[0017] [Non-Patent Document 1] TL Gustavson, PRECISION ROTATION SENSING USING ATOM INTERFEROMETRY, A DISSERTATION SUBMITTED TO THE DEPARTMENT OF PHYSICS AND THE COMMITTEE ON GRADUATE STUDIES OF STANFORD UNIVERSITY, 2000. Summary of the Invention [Problem to be solved by the invention]

[0018] Although the phase signal extraction of interference waves using lock-in detection is an excellent measurement method, further improvements are needed in the phase signal extraction method for atomic wave interferometers. [Means for solving the problem]

[0019] The disclosed technology provides a phase difference measurement method that solves the above-mentioned problems. This phase difference measurement method uses an atomic wave interferometer that splits an atomic wave with a first Raman beam, reflects it with a second Raman beam, and then splits it again with a third Raman beam for interference. The second Raman beam is given an offset phase and an oscillation phase with amplitude β and angular frequency ω to modulate the phase of the atomic wave. An atomic number counter measures the intensity signal I of the atomic interference wave. The observed phase difference Φ is calculated from the ω component, 2ω component, and amplitude β of the intensity signal I. The offset phase is subtracted from the observed phase difference Φ to obtain the measured phase difference. The offset phase is then feedback-controlled so that cosΦ = -1. The disclosed technology also provides an atomic wave interferometer that solves the above-mentioned problems. The atomic wave interferometer includes a Raman beam generator, an atomic beam source, an atom number counter, and a signal processor. The Raman beam generator further includes a laser light source, a branching filter, a frequency shifter, and a modulator. The signal processor further includes a fundamental wave component extractor, a second harmonic component extractor, a phase calculator, and a modulation signal generator. [Effects of the Invention]

[0020] According to the disclosed technology, the ratio of the ω component and the 2ω component of the intensity signal I does not depend on the input atomic wave intensity, so the phase can be measured without being affected by intensity drift. Furthermore, observing atomic waves in dark fringes can eliminate intensity noise and minimize shot noise. [Brief explanation of the drawings]

[0021] [Figure 1] A diagram explaining wave interference. [Figure 2] FIG. 1 is a diagram illustrating a laser interferometer gyroscope. [Figure 3] A diagram explaining the inelastic collision of a photon with an atom in Raman scattering. [Figure 4] A diagram explaining an atomic wave Mach-Zehnder interferometer that uses Raman scattering. [Figure 5] A diagram explaining the phase control of atomic waves using a second Raman beam. [Figure 6] A diagram explaining dark fringes and bright fringes. [Figure 7] A graph comparing the intensity noise of the phase modulation method and the intensity noise of the conventional method. [Figure 8] A comparison of shot noise using the phase modulation method and the conventional method. [Figure 9] FIG. 1 is a functional block diagram of an atomic wave interferometer according to a first embodiment. [Figure 10] FIG. 2 is a detailed functional block diagram of a signal processing unit according to the first embodiment. [Figure 11] FIG. 3 is a flowchart illustrating the operation of the atomic wave interferometer according to the first embodiment. [Figure 12] 10A and 10B are diagrams illustrating the difference between a phase difference derived from acceleration and a phase difference derived from angular velocity. [Figure 13] FIG. 10 is a functional block diagram of an atomic wave interferometer gyroscope according to a second embodiment. [Figure 14] FIG. 10 is a detailed functional block diagram of a signal processing unit according to a second embodiment. [Figure 15] FIG. 10 is a flowchart illustrating the operation of the atomic wave interferometer gyroscope according to the second embodiment. [Figure 16] 10 is a diagram for explaining the derivation of shot noise and intensity noise using field operators. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the disclosed technology will be described in detail. Note that components having the same functions are assigned the same numbers, and duplicated descriptions will be omitted. The present invention is characterized by observing the intensity of the interference result of phase-modulated atomic waves using dark fringes (described below). This is hereinafter referred to as the "dark fringe observation method." First, the principle of the "dark fringe observation method" will be explained, and then the atomic wave interferometer and gyroscope using the dark fringe observation method will be explained.

[0023] [Dark fringe observation method] In the prior art, the phase given to the atomic wave in Raman scattering is ω s The atomic wave observed is swept with t and the frequency is 2ω. s Lock-in detection was performed. In the disclosed technology, the atomic wave is θ(t)=βsinω m By adding t, the phase is oscillated, and the observed interference result ω m Component S1 and 2ω m The component S2 is extracted and the phase difference is detected by taking the ratio of S1 to S2 (phase modulation method). β is the amplitude that oscillates the phase of the atomic wave and is called the modulation index. When the modulation index is small, observing the atomic wave in the dark fringes eliminates intensity noise and minimizes shot noise. Therefore, the phase of the atomic wave is further adjusted with the Raman beam, and the interference results are observed in the dark fringes (operating point control).

[0024] <Phase modulation method> θ(t)=βsinω m The atomic wave is modulated at t. Atomic wave I observed at position T in Figure 5 m From equation (16),

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[0025] <Operating point control> If we plot equation (19) with the phase on the horizontal axis, we get the graph in Figure 6. The position where Δφ=2nπ is called the bright fringe, and the position where Δφ=(2n-1)π is called the dark fringe.

[0026] When the interference of phase-modulated atomic waves is observed as dark fringes, the intensity noise (classical noise) N C-D is given as a function of modulation index β by the following equation:

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[0027] When the interference results of phase-modulated atomic waves are observed as dark fringes, shot noise (noise originating from quantum fluctuations) N Q-D is given as a function of modulation index β by the following equation:

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[0028] For the above reasons, in the disclosed technology, the interference results of the phase-modulated atomic waves are controlled so that they can be observed in the dark fringes (operating point control). Operating point control and restoration of the measurement target phase are performed as follows. The target phase, such as the Sagnac phase, is set to Φ0, and the Raman beam is phase modulated with β sinω m t and phase shift Φ offset Then, the interference wave intensity I ctrl can be written as follows:

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[0029] [First embodiment] [Atomic wave interferometer] 9 is a functional block diagram showing an example of the configuration of an atomic wave interferometer 9 according to the first embodiment. The atomic wave interferometer 9 includes a laser light source 91, branching filters 92-1 to 92-5, attenuators 93-1 to 93-6, a phase modulator 94, frequency shifters 95-1 to 95-3, an atomic beam source 97, an interference wave detector 98, and a signal processing unit 99. 10 is a detailed functional block diagram of the signal processing unit 99. The signal processing unit 99 includes a fundamental wave component extraction unit 101, a second harmonic component extraction unit 102, a phase calculation unit 103, and a modulation signal generation unit 104. FIG. 11 is a flowchart illustrating an example of the operation of the atomic wave interferometer 9. This will be explained using Figures 9, 10, and 11.

[0030] [Formation of opposing Raman beams] First, as explained in the Mach-Zehnder interferometer above, we form opposing Raman beams that act as a splitter and mirror for the atomic waves. A laser beam (frequency ω1) generated by a laser light source 91 is split into six beams by splitters 92-1 to 92-5. One output of splitters 92-3, 92-4, and 92-5 is laser beams 96-1, 96-3, and 96-5 of frequency ω1. The other outputs A, B, and C of the demultiplexers 92-3, 92-4, and 92-5 are frequency-converted by a frequency shifter to become laser beams 96-2, 96-4, and 96-6 of frequency ω2. Thus, laser beams 96-1 and 96-2 form a first Raman beam, laser beams 96-3 and 96-4 form a second Raman beam, and laser beams 96-5 and 96-6 form a third Raman beam. For the sake of further explanation, we will refer to the system consisting of the atomic beam source, three Raman beams, and interference wave detector as the "interferometer system."

[0031] [Operation of atomic wave interferometer] The second Raman beam is modulated by a phase modulator 94 with a modulation signal (β sinω m t+Φ offset ) is applied. The signal processing unit 99 acquires the interference wave intensity signal observed by the interference wave detector 98 (step S1101). The fundamental wave component extraction unit 101 extracts S1 as explained above in the <Phase modulation method> (step S1102). The second harmonic component extracting unit 102 extracts S2 as explained above in the <Phase modulation method> (step S1103). The phase calculation unit 103 calculates the equation (23) and obtains Φ (=Δφ) in the equation (31) (step S1104).

[0032] The phase calculation unit 103 calculates the equation (32) to obtain Φ0 (step S1105), and outputs it as the measurement value of the target phase (step S1106). If you want to measure the angular velocity using an atomic wave interferometer, you can further calculate the angular velocity using equation (6). The modulation signal generator 104 calculates Φ so that cosΦ becomes −1. offset is updated (step S1107). The phase modulator 94 applies the updated modulation signal to the second Raman beam (step S1108).

[0033] [supplement] The interference wave intensity is the probability of one atom existing multiplied by the number of atoms supplied at the interference wave detector (position T in Figure 4). Therefore, the interference wave detector is specifically realized by a device that can measure the number of atoms. For example, the number of atoms can be estimated by irradiating position T with probe light and measuring the fluorescence emitted by atoms in state |g> or |e> with a photodetector or the like.

[0034] The above is a description of the atomic wave interferometer according to the first embodiment.

[0035] [Second embodiment] When the atomic wave interferometer of the first embodiment moves with acceleration, the atoms have mass, so the path becomes parabolic, and a phase difference resulting from the difference in path length occurs between path 1 and path 2. Therefore, the target phase observed by mounting an atomic wave interferometer on a moving object generally includes a phase difference resulting from acceleration in addition to angular velocity. The phase difference resulting from angular velocity (Sagnac phase) is expressed as φ Ω , the phase difference φ due to acceleration a Then, the target phase Φ0 is

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[0036] In a gyroscope intended to measure angular velocity, interferometers are arranged facing each other as shown in Fig. 12. The system including the atomic beam source 121 and the interferometer detector 122 will be called the first interferometer system, and the system including the second atomic beam source 123 and the second interferometer detector 122 will be called the second interferometer system. The lower path of the second interference system is path 3, the upper path is path 4, the phase observed by interference wave detector 122 is Φ1, and the phase observed by second interference wave detector 124 is Φ2. The phase derived from acceleration is the same for path 1 and path 3, and the same for path 2 and path 4, but the phase derived from angular velocity is reversed between path 1 and path 3 because the direction of travel of the atomic wave is reversed. The same is true for path 2 and path 4. Therefore,

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[0037] We would like to apply the dark fringe observation method to an atomic wave interferometer gyroscope. Therefore, we will examine the output of the second interferometer when the operating point of the first interferometer is controlled to the dark fringe.

[0038] <Operating point control of the first interference system> The output interference wave intensity of the first interferometer when phase modulation and offset are applied to the second Raman beam is I R Then,

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[0039] <Operating point of the second interference system> The interference wave intensity of the second interferometer is I L Then,

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[0040] [Atomic wave interferometer gyroscope] 13 is a functional block diagram showing an example of the configuration of an atomic wave interferometer gyroscope 13 according to the second embodiment. Hereinafter, the "atomic wave interferometer gyroscope" will be abbreviated as "atomic wave gyroscope." The atomic wave gyroscope 13 is configured by adding a second atomic beam source 131 and a second interference wave detector 132 to the atomic wave interferometer 9 , and by providing a second signal processing unit 133 instead of the signal processing unit 99 . Hereinafter, the system consisting of the atomic beam source 97, the first to third Raman beams, and the interference wave detector 98 will be referred to as the right interference system. The system consisting of the second atomic beam source 131, the first to third Raman beams, and the second interference wave detector 132 will be referred to as the left interference system. 14 is a detailed functional block diagram of the second signal processing unit 133. The second signal processing unit 133 has a configuration in which a second fundamental signal main wave component extraction unit 141, a second second harmonic wave component extraction unit 142, a second phase calculation unit 143, and an angular velocity calculation unit 144 are added to the signal processing unit 99 of the first embodiment. FIG. 15 is a flowchart illustrating an example of the operation of the atomic wave gyroscope 13. This will be explained using Figures 13, 14 and 15.

[0041] [Formation of opposing Raman beams] Counter-facing Raman beams are formed in the same manner as in the first embodiment.

[0042] [Operation of atomic wave gyroscope] The second Raman beam is modulated by a phase modulator 94 with a modulation signal (β sinω m t+Φ offset ) is applied.

[0043] <Operation of the first interferometer> The second signal processing unit 133 acquires the first interference wave intensity signal observed by the interference wave detector 98 (step S1501). The fundamental wave component extraction unit 101 extracts S1 as explained above in the <Phase modulation method> (step S1502). The second harmonic component extracting unit 102 extracts S2 as explained above in the <Phase modulation method> (step S1503).

[0044] The phase calculation unit 103 calculates the equation (23) and calculates Φ R (step S1504). The modulation signal generator 104 generates cosΦ R Φ so that is -1 offset is updated (step S1505). The phase modulator 94 applies the updated modulation signal to the second Raman beam (step S1506).

[0045] <Operation of the second interference system> The second signal processing unit 133 acquires the second interference wave intensity signal observed by the second interference wave detector 132 (step S1507). The second fundamental wave component extraction unit 141 extracts S1 as described above in the <Phase modulation method> (step S1508). The second second harmonic component extracting unit 142 extracts S2 as explained above in the <Phase modulation method> (step S1509).

[0046] The second phase calculation unit 143 calculates the equation (23) and calculates Φ L (Step S1510). As shown in equation (41), Φ L is -2 times the Sagnac phase. The angular velocity calculation unit 144 calculates the angular velocity Ω using the following formula (step S1511).

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[0047] The above is a description of the atomic wave gyroscope according to the second embodiment.

[0048] [More about intensity noise and shot noise] The output signal of an atomic wave interferometer corresponds to the number of atoms observed at the output port of the interferometer. In the following, we treat atomic waves using quantum field theory to calculate the fluctuations in the observed number of atoms.

[0049] <Field operators> For each of the atomic wave and atomic wave fluctuation, an operator (quadrature) that is orthogonally decomposed into amplitude and phase is used.

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[0050] <Propagation of atomic waves> This will be explained using FIG. The first Raman beam splits the atomic wave into two atomic waves with an amplitude of 1 / √2. The second Raman beam reflects the atomic wave and adds a phase to it. In Raman scattering, where the atomic wave loses momentum, the phase is θ(t)+θ', and in Raman scattering, where the atomic wave gains momentum, the phase is -(θ(t)+θ'). Here, θ(t)=βsinω m t, θ' is the tunable phase of the second Raman beam. The third Raman beam splits the Q → S atomic wave into two atomic waves with an amplitude of 1 / √2, and also splits the R → S atomic wave into two atomic waves with an amplitude of 1 / √2. Then, the atomic wave incident on the interferometer is A in → The interference wave B emitted to T → (t) becomes:

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[0051] When the Sagnac phase Φ due to the rotation shown in Figure 16 occurs in the interferometer, the waves that have rotated half a revolution interfere in the atomic wave interferometer, so

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[0052] If the intensity of the atomic wave is I,

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[0053] <Output interference wave: dark fringe> Dark fringe interference wave B D → (t) is given by equation (51) by substituting 2θ'=(2n-1)π into equation (49).

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[0054] <Propagation of atomic wave fluctuations> The relationship between atomic wave fluctuations at each point in Figure 16 is as follows:

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[0055] To observe in the dark fringe, the adjustable phase 2θ'=(2n-1)π is used, and to observe in the bright fringe, 2θ'=2nπ is used. <Output atomic wave fluctuations: dark fringes> Atomic wave fluctuations in dark fringes b D → (t) is given by equation (55) by substituting 2θ'=(2n-1)π into equation (54).

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[0056] <Shot noise: dark fringes> Signal strength δP derived from phase difference sig-D From the first and second terms of equation (51), equation (57) is obtained.

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[0057] On the other hand, the intensity fluctuation δP, which includes the signal and noise, detected by the atomic number detector D From equation (51) and equation (55),

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[0058] The power spectral density of the shot noise is given by the following equation (62) using the coefficients a1 and g2 in equation (61) (Reference: A. Buonanno et. al., Phys. Rev. D 67, 122005, 2003).

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[0059] <Shot noise: bright fringes> Equation (28) can be obtained from the bright fringe equations (52) and (56) by a similar procedure.

[0060] <Intensity noise: dark fringes> If we ignore the vacuum field g2 in equation (62) (set it to zero) and calculate the classical fluctuations as ε times the vacuum field fluctuations, the power spectral density S of the classical intensity fluctuations is int-D This becomes:

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[0061] <Intensity noise: bright fringe> Similarly, by assuming the vacuum field to be zero, we obtain equation (25).

[0062] <Conventional method: shot noise> When dealing with atomic interference waves and atomic wave fluctuations using the conventional method, θ(t)+θ'=ω in equations (49) and (54) s Let t be the time. Interference wave B' emitted to T → (t), atomic wave fluctuation b → (t) is

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[0063] <Conventional method: intensity noise> Intensity noise S int-Conv is calculated by assuming the vacuum field to be zero in equation (72)

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[0064] This concludes the detailed explanation of noise. [Explanation of symbols]

[0065] 20, 91 Laser light source 21, 23 Half mirror 22, 24 Mirror 41, 97, 121 Atomic radiation sources 42, 98, 122 Interference detector 43 First Raman beam 44 Second Raman beam 45 Third Raman beam 92-1 to 92-5 splitters 93-1 to 93-6 Attenuators 94 Phase Modulator 95-1 to 95-3 Frequency Shifters 96-1, 96-3, 96-5 Laser beam with frequency ω1 96-2, 96-4, 96-6 Laser beam with frequency ω2 99 Signal Processing Section 101 Fundamental wave component extraction section 102 Double wave component extraction section 103 Phase calculation section 104 Modulation signal generator 123, 131 Second atomic radiation source 124, 132 Second interference wave detector 133 Second signal processing section 141 2nd fundamental wave component extraction section 142 Second harmonic component extraction section 143 Second phase calculation section 144 Angular velocity calculation section

Claims

1. A phase difference measurement method using an atomic wave interferometer, in which an atomic wave is split by a first Raman beam, reflected by a second Raman beam, and split again by a third Raman beam to cause interference, comprising: an offset phase and an oscillation phase having an amplitude β and an angular frequency ω are applied to the second Raman beam to modulate the phase of the atomic wave; The atomic interference wave intensity signal I is measured using an atomic number counter; calculating an observed phase difference Φ from the ω component and 2ω component of the intensity signal I and the amplitude β; calculating a measured phase difference by subtracting the offset phase from the observed phase difference Φ; The offset phase is feedback controlled so that cosΦ=-1. Phase difference measurement method.

2. a Raman beam generator; an atomic beam source; an atomic number measuring instrument; a signal processing unit, The Raman beam generating unit The optical fiber includes a laser light source, a demultiplexer, a frequency shifter, and a modulator, The signal processing unit a fundamental wave component extractor, a second harmonic component extractor, a phase calculator, and a modulation signal generator; An atomic wave interferometer comprising:

3. A method for measuring angular velocity using a dual atomic wave interferometer, in which an atomic wave is split by a first Raman beam, reflected by a second Raman beam, and split again by a third Raman beam to cause interference, comprising: an offset phase and an oscillation phase having an amplitude β and an angular frequency ω are applied to the second Raman beam to modulate the phase of the atomic wave; The first atomic interference wave intensity signal I Ｒ Measure The intensity signal I Ｒ The first observed phase difference Φ is calculated from the ω component and 2ω component of Ｒ Calculate cosΦ Ｒ feedback-controlling the offset phase so that The intensity signal I of the second atomic interference wave is measured by the second atomic number counter. Ｌ Measure The intensity signal I Ｌ The second observation phase difference Φ is calculated from the ω component and 2ω component of Ｌ Calculate Said second observed phase difference Φ Ｌ Calculate the angular velocity Ω from Angular velocity measurement method.

4. a Raman beam generator; two atomic beam sources; Two atomic number measuring instruments, a signal processing unit, The Raman beam generating unit The optical fiber includes a laser light source, a demultiplexer, a frequency shifter, and a modulator, The signal processing unit Two fundamental wave component extractors, two double wave component extractors, two phase calculators, a modulation signal generator, and an angular velocity calculator. A gyroscope comprising:

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