Quantum collimation method for atomic beam, quantum collimator for atomic beam, atom interferometer, and atomic gyroscope

Abstract

To collimate an atomic beam by using laser beams, without requiring high-precision parallel arrangement of the laser beams.SOLUTION: An atomic beam 110 is subjected to quantum collimation. The atomic beam 110 is irradiated with a pumped laser beam 701a and a filtering laser beam 701b in this order. The pumped laser beam 701a has a wavelength corresponding to transition between a ground state and an excited state of an atom contained in the atomic beam 110. The atom is transitioned from the ground state to the excited state, and further, the atom is relaxed from the excited state to a metastable state, according to irradiation of the pumped laser beam 701a. The filtering laser beam 701b has a wavelength corresponding to transition between the ground state and the metastable state. According to irradiation of the filtering laser beam 701b, an atom of the metastable state having a velocity component that is the same as a prescribed velocity component Δv or smaller than Δv, in a travel direction of the filtering laser beam 701b, is transitioned to the ground state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to techniques for quantum collimating atomic beams. [Background technology]

[0002] In recent years, collimated atomic beams have been used in atom beam lithography, atom interferometers, and the like. Known techniques for collimating an atomic beam include a technique for collimating an atomic beam emitted from an atomic beam source using multiple slits spaced apart in the direction of travel of the atomic beam (see, for example, the configuration shown in FIG. 2 of Non-Patent Document 1), a technique for collimating using a two-dimensional magneto-optical trap (2D-MOT) mechanism (see, for example, Non-Patent Document 2), and a technique for collimating using at least three laser beams arranged parallel to each other (see, for example, Patent Document 1). In particular, the collimation technique disclosed in Patent Document 1 is excellent in that it can be implemented in a small size (particularly, a small size in the direction of travel of the atomic beam) and can reduce the decrease in atomic flux while achieving good collimation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent No. 6713643 [Non-patent literature]

[0004] [Non-Patent Document 1] St. Bernet, R. Abfalterer, C. Keller, M. Oberthaler, J. Schmiedmayer and A. Zeilinger, “Matter waves in time-modulated complex light potentials,” Phys. Rev. A 62, 023606 (2000). [Non-Patent Document 2] J. Schoser, A. Batar, R. Low, V. Schweikhard, A. Grabowski, Yu. B. Ovchinnikov, and T. Pfau, “Intense source of cold Rb atoms from a pure two-dimensional magneto-optical trap,” PHYSICAL REVIEW A, 66, 023410 2002. Summary of the Invention [Problem to be solved by the invention]

[0005] The collimation technique disclosed in Patent Document 1 is an excellent collimation technique as described above, but requires two laser beams to be arranged in parallel with high accuracy. The collimation technique disclosed in Patent Document 1 transitions atoms having a sufficiently small predetermined speed component in a direction perpendicular to the traveling direction of the atomic beam (the "orthogonal direction") from the ground state to a first excited state by the first laser beam, imparts momentum to atoms in the ground state (i.e., atoms other than those having a sufficiently small predetermined speed component in the orthogonal direction) before the atoms in the first excited state fall to the ground state by spontaneous emission by the second laser beam, and further returns atoms having a sufficiently small predetermined speed component in the orthogonal direction from the first excited state to the ground state by the third laser beam, thereby achieving good collimation of the atomic beam. Therefore, it is particularly required that the first laser beam and the third laser beam are arranged in parallel with each other with high accuracy. Otherwise, the atoms resonating with the first laser beam will not resonate with the third laser beam, and thus it will be difficult to return the energy eigenstate of the atoms having a sufficiently small predetermined velocity component in the orthogonal direction from the first excited state to the ground state. As an example of the accuracy, the relative angle between the first laser beam and the third laser beam is less than 0.1 milliradian (mrad).

[0006] In view of the above background and technical problems, a technique is disclosed for collimating an atomic beam using a laser beam without requiring highly accurate parallel alignment of the laser beam. [Means for solving the problem]

[0007] The technical matters described herein are not intended to explicitly or implicitly limit the invention described in the claims, nor to enable those who benefit from the invention (e.g., the applicant and the right holder) to limit the invention described in the claims, but are merely provided to facilitate understanding of the gist of the invention. The outline of the invention from other perspectives can be understood, for example, from the claims at the time of filing of this patent application.

[0008] The above-mentioned prior art is a technique for physically collimating an atomic beam, whereas the collimation technique of the present disclosure is a technique for quantum collimating an atomic beam. "Physical collimation" is narrowing the width of an atomic beam, which has a dimension of length, whereas "quantum collimation" is making only atoms contained in the atomic beam moving in a certain direction while spreading out--more precisely, atoms having a speed component equal to or smaller than a predetermined speed component Δv in the traveling direction of a filtering laser beam, which will be described later--into a desired energy eigenstate. In other words, according to "quantum collimation," the width of the atomic beam is not controlled, but in the atomic beam, atoms in a desired energy eigenstate have a speed component equal to or smaller than a predetermined speed component Δv in a direction perpendicular to the aforementioned certain direction in the atomic beam, and therefore, from the viewpoint of quantum theory, the atomic beam is collimated with respect to the aforementioned certain direction. Even if atoms in a desired energy eigenstate and atoms in other energy eigenstates coexist in an atomic beam, the atoms in the other energy eigenstates are insensitive to light interacting with the atoms in the desired energy eigenstate, so a quantum collimated atomic beam is practical. However, it is desirable that the lifetimes of the other energy eigenstates are as long as possible. From the viewpoint of collimation, Δv is usually set to a sufficiently small value, but the specific value of Δv is determined depending on the actual example.

[0009] The disclosed method is a method for quantum collimating an atomic beam, which includes irradiating the atomic beam with a pumping laser beam having a wavelength corresponding to the transition between the ground state and the excited state of the atoms contained in the atomic beam, thereby transitioning the atoms contained in the atomic beam from the ground state to an excited state, and further relaxing the excited state to a metastable state of the atoms, and irradiating the atomic beam with a filtering laser beam having a wavelength corresponding to the transition between the ground state and the metastable state after the irradiation with the pumping laser beam, thereby transitioning the metastable atoms contained in the atomic beam, which have a speed component equal to or smaller than a predetermined speed component Δv in the traveling direction of the filtering laser beam, to the ground state.

[0010] The collimator of the present disclosure is a collimator for quantum collimating an atomic beam. The collimator includes an irradiation device configured to irradiate the atomic beam with pumping laser light and filtering laser light in this order. The pumping laser light is laser light having a wavelength corresponding to the transition between the ground state and the excited state of atoms contained in the atomic beam. The filtering laser light is laser light having a wavelength corresponding to the transition between the metastable state and the ground state that the excited state atoms transition to in the relaxation process. Effect of the Invention

[0011] According to the technique of the present disclosure, it is possible to collimate an atomic beam using a laser beam without requiring highly accurate parallel positioning of the laser beam. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram for explaining quantum collimation of a thermal atomic beam. [Diagram 2] FIG. 1 is a diagram for explaining quantum collimation of cold atomic beams. [Diagram 3] FIG. 1 is a diagram for explaining the relationship between the ground state, an excited state, and a metastable state. [Figure 4] Graph showing the relationship between the atomic speed component in the direction of laser light propagation and the population of atoms that have transitioned from a metastable state to the ground state. [Diagram 5] FIG. 1 is a diagram for explaining a Mach-Zehnder type atom interferometer that uses an atom beam collimator. [Figure 6] An example of the configuration of an atom interferometer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The embodiments of the present invention will be described with reference to the drawings. Note that the drawings are for the purpose of understanding the embodiments, and the dimensions of each component shown in the drawings differ from the actual dimensions.

[0014] In the illustrated embodiment, the collimator 700 quantum collimates the atomic beam 110 from the atomic beam source 100 contained within the vacuum vessel 200 .

[0015] The atom beam source 100 continuously generates an atomic beam 110. The atomic beam 110 may be a thermal atomic beam or a cooled atomic beam. Below, an example of the configuration of the atom beam source 100 that continuously generates a thermal atomic beam and an example of the configuration of the atom beam source 100 that continuously generates a cooled atomic beam will be described.

[0016] An atom beam source 100 that continuously generates a thermal atomic beam includes, for example, a heater 100a and a nozzle 100b that communicates with the heater 100a (see FIG. 1). The heater 100a generates gaseous atoms by heating a solid made of a single element with high purity. The gaseous atoms obtained by the heater 100a exit the atom beam source 100 from the heated nozzle 100b as a thermal atomic beam. See FIG. 1 in Reference 1 for an example of the configuration of such an atom beam source 100. (Reference 1) Cvejanovic D and Murray AJ, “Design and characterization of an atomic beam oven for combined laser and electron impact experiments,” Meas. Sci. Tech. 13 1482-1487 (2002).

[0017] The direction of travel of the thermal atomic beam is the direction of extension of the line obtained by connecting the peaks of the density distribution of atoms contained in the thermal atomic beam, and usually coincides with the ejection direction of the nozzle 100b (i.e., the direction of extension of the central axis of the nozzle 100b). The flow of gas atoms narrowed down by the outlet hole located at the tip of the nozzle 100b is not a parallel flow but an ejection flow ejected at a small solid angle, so the thermal atomic beam contains atoms having a speed component in a direction perpendicular to the direction of travel of the thermal atomic beam. The average speed of the atoms contained in the thermal atomic beam in the direction of travel of the thermal atomic beam is approximately several hundred m / s (Rb: up to 300 m / s, Yb: up to 300 m / s, Ca: up to 600 m / s).

[0018] The atom beam source 100 that continuously generates a cooled atomic beam includes, for example, a gas atom generator 100c and a laser cooler 100d (see FIG. 2).

[0019] The gas atom generator 100c has a structure in which a solid sublimes or a liquid evaporates or volatilizes, and generates gas atoms. The solid or liquid is preferably made of a single element of high purity. When strontium or calcium is used, the heater 100a is required, but when rubidium or cesium is used, the saturated vapor pressure at room temperature (a temperature suitable for human activity) is high (i.e., it is easy to vaporize), so sufficient gas atoms can be obtained without using the heater 100a. The gas atoms (hereinafter simply referred to as atoms) that fill one section of the vacuum vessel 200 are naturally supplied to the laser cooler 100d.

[0020] The laser cooler 100d may be, for example, a two-dimensional magneto-optical trap (2D-MOT) mechanism including a magnetic field generating coil called hairpin wires and two cooling laser light pairs, or a 2D MOT mechanism having a configuration in which one laser light pair along the zero magnetic field line of a two-dimensional quadrupole magnetic field is added to the 2D-MOT mechanism. + The laser cooler 100d may include a Zeeman decelerator as necessary. Alternatively, the mechanism disclosed in Reference 2 may be employed as the laser cooler 100d. The laser cooler 100d generates a cooled atomic beam from a cooled atomic ensemble trapped in space. (Reference document 2) Japanese Patent Application Publication No. 2020-020636

[0021] Since the cooled atomic beam from the atomic beam source 100 is not a parallel flow but a flow that spreads over a small solid angle, the cooled atomic beam contains atoms with a speed component in a direction perpendicular to the traveling direction of the cooled atomic beam. The traveling direction of the cooled atomic beam is the direction of extension of a line obtained by connecting the peaks of the density distribution of the atoms contained in the cooled atomic beam. The average speed of the atoms contained in the cooled atomic beam in the traveling direction of the cooled atomic beam is approximately several tens of meters per second.

[0022] Hereinafter, the direction perpendicular to the traveling direction of the atomic beam 110 will be simply referred to as the perpendicular direction.

[0023] As described above, the collimation technique of the present disclosure does not control the width of the atomic beam itself, but rather puts only atoms moving in a certain direction in the expanding atomic beam into a desired energy eigenstate. The outline of an embodiment based on this concept is as follows. First, the atomic beam is irradiated with a first laser beam (also referred to as pumping laser beam in this specification) having a wavelength corresponding to the transition between the ground state and the excited state of the atoms contained in the atomic beam. As a result, almost all atoms contained in the atomic beam transition from the ground state to the excited state, and further relax from the excited state to a metastable state. After the irradiation of the first laser beam, the atomic beam is irradiated with a second laser beam (also referred to as filtering laser beam in this specification) having a wavelength corresponding to the transition between the ground state and the metastable state. As a result, only atoms having a speed component equal to or smaller than a predetermined speed component Δv in the traveling direction of the second laser beam transition from the metastable state to the ground state. Therefore, the atomic beam irradiated with the first laser beam and the second laser beam in this order generally includes (a) atoms in a ground state having a speed component in the propagation direction of the second laser beam that is equal to or smaller than a predetermined speed component Δv, and (b) atoms in a metastable state having a speed component larger than the predetermined speed component Δv in the propagation direction of the second laser beam.

[0024] In such an embodiment, two laser beams (preferably Gaussian beams) are used, which are aligned along the direction of travel of the atomic beam. The arrangement of the two laser beams along the direction of travel of the atomic beam can have a total length shorter than the interval between the slits in the direction of travel of the atomic beam in the atomic beam collimation technique using a slit. In addition, the collimation technique of the present disclosure does not block the travel of the atoms, so that the decrease in atomic flux can be reduced compared to the atomic beam collimation technique using a slit. Furthermore, the collimation technique of the present disclosure selects only atoms that have a speed component equal to or smaller than a predetermined speed component Δv in the direction of travel of the second laser beam, so that good collimation can be achieved. In addition to these features, according to the collimation technique of the present disclosure, since the first laser beam is a laser beam for optical pumping, the direction of travel of the first laser beam does not need to be perpendicular to the direction of travel of the atomic beam, and the first laser beam and the second laser beam do not need to be arranged parallel to each other with high accuracy. Details of this embodiment will be described below. In the following description, the first laser light is referred to as a pumping laser light, and the second laser light is referred to as a filtering laser light.

[0025] The atomic beam 110 enters a collimator 700 (see FIGS. 1 and 2). The collimator 700 includes an irradiation device 710 configured to independently irradiate the atomic beam 110 with a pumping laser beam 701a and a filtering laser beam 701b in this order. Thus, the atomic beam 110 is independently irradiated with the pumping laser beam 701a and the filtering laser beam 701b in the course of the atomic beam 110's travel.

[0026] Since the pumping laser light 701a is a laser light for optical pumping, it is not necessary to perform highly accurate angle adjustment to make the irradiation direction of the pumping laser light 701a (i.e., the traveling direction of the pumping laser light 701a) perpendicular to the traveling direction of the atomic beam 110. For example, the angle between the traveling direction of the pumping laser light 701a and the traveling direction of the atomic beam 110 may deviate from 90 degrees by 10 degrees or more. Just to be sure, the angle between the traveling direction of the pumping laser light 701a and the traveling direction of the atomic beam 110 may deviate significantly from 90 degrees, but usually there is no particular advantage to such a configuration.

[0027] Furthermore, highly accurate angle adjustment is not required to make the irradiation direction of the filtering laser beam 701b (i.e., the traveling direction of the filtering laser beam 701b) perpendicular to the traveling direction of the atomic beam 110. This is because, among the atomic beam 110 traveling while spreading, atoms traveling in a direction roughly perpendicular to the traveling direction of the filtering laser beam 701b transition from a metastable state to a ground state. In other words, atoms traveling in a direction roughly perpendicular to the traveling direction of the filtering laser beam 701b have a speed component that is equal to or smaller than a predetermined sufficiently small speed component Δv in the traveling direction of the filtering laser beam 701b. In short, since the atomic beam 110 is collimated in a direction roughly perpendicular to the traveling direction of the filtering laser beam 701b, there is no need to set the traveling direction of the filtering laser beam 701b in relation to the traveling direction of the atomic beam 110. However, from the viewpoint of the flux of the quantum collimated atomic beam 110, it is preferable to make the traveling direction of the filtering laser light 701b as perpendicular as possible to the traveling direction of the atomic beam 110. Furthermore, in relation to the interference device 250 described later, it is preferable that the traveling direction of the filtering laser light 701b is parallel to the traveling directions of three traveling optical standing waves 201a, 201b, and 201c described later.

[0028] The pumping laser light 701a will now be described. The pumping laser light 701a has a wavelength λ1 that corresponds to the transition between the ground state and the excited state of the atoms contained in the atomic beam 110. Almost all of the atoms contained in the atomic beam 110 transition from the ground state to an excited state by passing through the pumping laser light 701a, and then relax from the excited state to a metastable state (first step).

[0029] Since this relaxation process is a stochastic process, it is desirable that the pumping laser light 701a satisfies condition X for atoms contained in the atomic beam 110 to relax to a metastable state with a certain probability while passing through the pumping laser light 701a. Hereinafter, the condition X in the relaxation process of the Λ-type three-level system (see FIG. 3) will be described.

[0030] In a Λ-type three-level system, an excited atom relaxes from the excited state to the ground state or metastable state. Consider the case where the power density of the pumping laser light 701a is sufficiently greater than the saturation intensity of the transition between the ground state and the excited state. The width of the pumping laser light 701a in the region of the pumping laser light 701a through which the atomic beam 110 passes is W [unit: m], the average value of the speed component of the atoms contained in the atomic beam 110 in the traveling direction of the atomic beam 110 is v [unit: m / s], the number of relaxation times required for the atoms contained in the atomic beam 110 to relax from the excited state to the metastable state with a predetermined probability in the relaxation process is N, and the expected value of the time required for the excited atom contained in the atomic beam 110 to relax only once is E. Condition X is expressed as in Equation (1), since the time W / v required for the atom to cross the pumping laser light 701a is greater than the time E×N required for N relaxations to occur. In the case of spontaneous emission, the lifetime of the excited state is τ, the number of excited atoms at time t is N(t), and e is the Napier's constant, so N(t) = N(0) × e -t / τis satisfied (1 / τ is Einstein's A coefficient). Therefore, when the expected value E is, for example, N(t) / N(0) = 0.01, E = -τln(0.01) ≈ 4.6τ. More specifically, in the process of repeating optical pumping and relaxation, in order to make the atomic energy eigenstate metastable with a probability of β (0 < β < 1), it is only necessary that the probability that the atomic energy eigenstate after N relaxations is the ground state is less than 1 - β. Therefore, Equation (2) must hold. Equation (2) is equivalent to Equation (3). In Equation (2) and Equation (3), R is the branching ratio (0 < R < 1) from the excited state to the metastable state of the atoms contained in the atomic beam 110. Therefore, Equation (4) is obtained. From the perspective of making the energy eigenstates of almost all the atoms contained in the atomic beam 110 metastable by irradiating the pumping laser light 701a to the atomic beam 110, the value of β is preferably large, for example, β ≥ 0.99.

Number

[0031] As described above, when the power density I of the pumping laser light 701a is sufficiently larger than the saturation intensity I s between the ground state and the excited state, Equation (5) holds for the power P of the pumping laser light 701a.

Number

[0032] Next, the filtering laser beam 701b will be described. The filtering laser beam 701b has a wavelength λ2 corresponding to the transition between the ground state of the atoms contained in the atomic beam 110 and the metastable state of the atoms. The energy eigenstate of almost all the atoms contained in the atomic beam 110 after the first step is a metastable state, but the metastable atoms contained in the atomic beam 110 that have a speed component equal to or smaller than a predetermined speed component Δv in the traveling direction of the filtering laser beam 701b transition from the metastable state to the ground state by passing through the filtering laser beam 701b (second step).

[0033] Here, the maximum value Δv of the speed component of the atom in the traveling direction of the filtered laser beam 701b will be described. t (i.e., v t =0) The spectral lines of the atoms are broadened by the transit-time broadening σ ttb If the filtered laser light 701b is a Gaussian beam, the beam waist of the Gaussian beam (which is 1 / (e 2 ) based on the half-width (w [unit: m]), transit-time broadening σ ttb It is known that the natural width Γ is expressed by equation (6). ttb is sufficiently narrow compared to Γ≪σ ttb ) the power density I of the filtered laser light 701b for the optical transition f If is sufficiently weak (i.e., I f <I s ) is the spectral linewidth due to transit-time broadening σ ttb However, the power density I fis not sufficiently weak, it is necessary to take into consideration the effect of the effective Rabi frequency between the ground state and the metastable state changing depending on the frequency of the filtering laser light 701b. Therefore, the spectral width changed by this effect is expressed by equation (7) using a correction coefficient α. Therefore, the maximum value Δv is expressed by the relationship ω doppler =kv t where k is the wave number of the filtered laser light 701b. In this regard, the optical Bloch equations for the two-level system in the Gaussian beam are expressed by the simultaneous differential equations of equations (9) and (10). In the simultaneous differential equations, Ω(t) is the Rabi frequency at time t, Ω0 is the Rabi frequency at time t=0, and σ t = w / (2v), and |c g (t)| 2 is the ground state population, and |c sub (t)| 2 is the population of the metastable state, k is the wave number of the Gaussian beam, and i is the imaginary unit. In the initial state, c g (-∞)=0,c sub (-∞)=1 (this is the initial value for a sufficiently long finite time range in numerical calculations). In the direction of travel of the Gaussian beam, the velocity component v t Let ω be the frequency of the Gaussian beam seen by an atom with ω, and ω0 be the resonance frequency between the energy level of the ground state and the energy level of the metastable state, then ω=ω0+kv t In the traveling direction of the laser beam 701b, the velocity component v t (i.e., v t =0) Under conditions that change the state of atoms from a metastable state to the ground state 100% (π pulse conditions), v t The results of the numerical calculation of the simultaneous differential equations for each value of v tFigure 4 shows a graph that represents the relationship between the population of atoms that have transitioned from a metastable state to the ground state at time t = ∞ (the final value of a sufficiently long finite time range in numerical calculations). By Gaussian fitting of the graph shown in Figure 4, the linewidth σ of the spectral line of atoms that crosses the Gaussian beam and has a speed component in the direction of travel of the Gaussian beam is obtained. ω As a result of calculating σ ω ≒0.95σ ttb Therefore, under the conditions of maximum efficiency for transitioning atoms from the metastable state to the ground state (π pulse conditions), α ≈ 0.95.

number

[0034] The atom in the atomic beam 110 is ytterbium ( 174 A specific example in which the pumping laser light 701a is a quark having an energy level of the ground state ( 1 S0) and excited state energy levels ( 3 D2) (see FIG. 3). The lifetime τ1 of the excited state is 460 ns. The filtered laser light 701b is 1 S0) and the metastable energy level ( 3 The natural width Γ of the transition between the ground state and the metastable state is about 2π×10 mHz, and the lifetime τ2 of the metastable state is about 10 s. The average value v of the speed components of the atoms contained in the atomic beam 110 in the traveling direction of the atomic beam 110 is 30 m / s, and the beam waist w of the filtered laser light 701b is 1 mm. In this specific example, the natural width Γ (about 2π×10 mHz) corresponds to the transit-time broadening σ ttb Since the distance is sufficiently narrow compared to the distance Δv, from equation (8) as described above, Δv = 2.3 × 10 -3 (m / s) is calculated and it is therefore found that good quantum collimation can be achieved.

[0035] In the above embodiment, the two laser beams (pumping laser beam 701a, filtering laser beam 701b) that satisfy the above conditions are realized by appropriately setting the beam waist, wavelength, and light intensity. The beam waist can be set optically (for example, by focusing the laser beam with a lens), and the light intensity can be set electrically (for example, by adjusting the output). In other words, the configuration of each laser beam generating device is not different from the conventional configuration, so the description of the configuration of the irradiation device 710 in which the two laser beam generating devices are arranged side by side will be omitted (laser light sources 721, 722 and lens 740 are roughly illustrated in FIG. 1 and FIG. 2).

[0036] Next, a Mach-Zehnder type atomic gyroscope 600 using the above-mentioned collimator 700 will be described. The Mach-Zehnder type atomic gyroscope 600 includes a Mach-Zehnder type atom interferometer 500 and an observation device 400 (see FIG. 5). The Mach-Zehnder type atom interferometer 500 includes an atom beam source 100, a collimator 700, an interference device 250, and a traveling optical standing wave generating device 350 (see FIG. 5). In this example, the atom beam source 100, the interference device 250, and the observation device 400 are accommodated in a vacuum vessel 200 (the vacuum vessel 200 is not shown in FIG. 5).

[0037] As described above, the atomic beam 110a quantum-collimated by the collimator 700 enters the interference device 250. Since the atomic beam 110a entering the interference device 250 contains atoms in a metastable state, it is preferable to perform subsequent processing on the atomic beam 110a in a time as short as possible as compared with the lifetime of the metastable state. Although there is no definitive definition of the lifetime of the metastable state, the lifetime of the metastable state is generally relatively long. Therefore, it is expected that subsequent processing can be completed in a time shorter than the lifetime of the metastable state. For example, when the lifetime τ2 of the metastable state is about 10 s, the average value v of the speed components of the atoms contained in the atomic beam 110 in the traveling direction of the atomic beam 110 is 30 m / s, and the total length of the interference device 250 is 1 m, the time for subsequent processing is at most (1 / 30) s, which is sufficiently shorter than the lifetime τ2 of the metastable state.

[0038] Before describing the interference device 250, the traveling light standing wave generating device 350 will be described. The Mach-Zehnder type atom interferometer 500 utilizes n-th order (where n is a predetermined positive integer equal to or greater than 2) Bragg diffraction. The traveling light standing wave generating device 350 generates three traveling light standing waves (a first traveling light standing wave 201a, a second traveling light standing wave 201b, and a third traveling light standing wave 201c) that satisfy the n-th order Bragg condition. The first traveling light standing wave 201a also satisfies the condition that it functions as a splitter of the atomic beam, the second traveling light standing wave 201b functions as a mirror of the atomic beam, and the third traveling light standing wave 201c functions as a combiner of the atomic beam.

[0039] The three traveling light standing waves (first traveling light standing wave 201a, second traveling light standing wave 201b, third traveling light standing wave 201c) that satisfy these various conditions are realized by appropriately setting the beam waist, wavelength, light intensity, and further the difference frequency between the opposing laser lights of the Gaussian beam. The beam waist of the Gaussian beam can be optically set (for example, by focusing the laser light with a lens), and the light intensity of the Gaussian beam can be electrically set (for example, by adjusting the output of the Gaussian beam). In other words, the generation parameters of the traveling light standing waves are different from the conventional generation parameters, and the configuration of the traveling light standing wave generating device 350 that generates these three traveling light standing waves is not different from the conventional configuration, so the description of the configuration of the traveling light standing wave generating device 350 is omitted (in FIG. 5, a laser light source, a lens, a mirror, an AOM, etc. are illustrated as an outline). For details of the configuration of the traveling light standing wave generating device 350, please refer to Reference 3 below. (Reference 3) Japanese Patent No. 6818332

[0040] In the interference device 250, the atomic beam 110a passes through three traveling optical standing waves 201a, 201b, and 201c. In the atomic interferometer of this example, a transition between two different momentum states |g, p0> and |g, p1> in the same internal state due to light irradiation is utilized. Here, the state |g> is the ground state of the atoms contained in the atomic beam 110a quantum-collimated by the collimator 700. In other words, the processing target of the Mach-Zehnder type atomic interference, which is the subsequent processing, is the ground state atoms contained in the atomic beam 110a quantum-collimated by the collimator 700. For this reason, in the following description, the flow of ground state atoms contained in the quantum-collimated atomic beam 110a is referred to as the converged atomic beam 110b.

[0041] When the focused atomic beam 110b passes through the first traveling optical standing wave 201a, the state of each atom, which is initially in |g, p0>, changes to a superposition state of |g, p0> and |g, p1>. If the interaction between the first traveling optical standing wave 201a and the atom is appropriately set (the beam waist, wavelength, optical intensity, and difference frequency between the opposing laser beams are appropriately set, respectively), the ratio of the existence probability of |g, p0> to the existence probability of |g, p1> immediately after passing through the first traveling optical standing wave 201a becomes 1:1. The atom acquires the momentum (=p1-p0) of 2n photons when transitioning from |g, p0> to |g, p1> through the absorption and emission of 2n photons traveling in opposite directions. Therefore, the direction of motion of the atom in the state |g, p1> is significantly deviated from the direction of motion of the atom in the state |g, p0>. That is, when the focused atomic beam 110b passes through the first traveling optical standing wave 201a, the focused atomic beam 110b is split into an atomic beam made of atoms in the state |g, p0> and an atomic beam made of atoms in the state |g, p1> at a ratio of 1:1. The traveling direction of the atomic beam made of atoms in the state |g, p1> is a direction based on the n-th order Bragg condition. The angle between the direction of the zeroth order light (i.e., the traveling direction of the atomic beam made of atoms in the state |g, p0> that has not been subjected to Bragg diffraction) and the direction based on the n-th order Bragg condition is n times the angle between the direction of the zeroth order light and the direction based on the first order Bragg condition. That is, the spread (in other words, the deviation) of the traveling direction of the atomic beam made of atoms in the state |g, p0> and the traveling direction of the atomic beam made of atoms in the state |g, p1> can be increased.

[0042] After the splitting, the atomic beam consisting of atoms in the state |g, p0> and the atomic beam consisting of atoms in the state |g, p1> pass through the second traveling optical standing wave 201b. At this time, if the interaction between the second traveling optical standing wave 201b and the atoms is appropriately set (the beam waist, the wavelength, the light intensity, and the difference frequency between the opposing laser lights are appropriately set, respectively), the atomic beam consisting of atoms in the state |g, p0> is inverted to an atomic beam consisting of atoms in the state |g, p1> during the passage process by passing through the second traveling optical standing wave 201b, and the atomic beam consisting of atoms in the state |g, p1> is inverted to an atomic beam consisting of atoms in the state |g, p0> during the passage process. At this time, for the former, the traveling direction of the atoms that have transitioned from |g, p0> to |g, p1> deviates from the motion direction of the atoms in the state |g, p0> as described above. As a result, the traveling direction of the atomic beam made of atoms in the state |g, p1> after passing through the second traveling light standing wave 201b becomes parallel to the traveling direction of the atomic beam made of atoms in the state |g, p1> after passing through the first traveling light standing wave 201a. In addition, in the latter case, the atom loses the same momentum as the momentum gained from 2n photons when transitioning from |g, p1> to |g, p0> through the absorption and emission of 2n photons traveling in opposite directions. In other words, the motion direction of the atom that transitioned from |g, p1> to |g, p0> deviates from the motion direction of the atom in the state |g, p1> before the transition. As a result, the traveling direction of the atomic beam made of atoms in the state |g, p0> after passing through the second traveling light standing wave 201b becomes parallel to the traveling direction of the atomic beam made of atoms in the state |g, p0> after passing through the first traveling light standing wave 201a.

[0043] After the inversion, the atomic beam consisting of atoms in the state |g, p0> and the atomic beam consisting of atoms in the state |g, p1> pass through the third traveling light standing wave 201c. At this time, the atomic beam consisting of atoms in the state |g, p0> after the inversion and the atomic beam consisting of atoms in the state |g, p1> after the inversion cross each other. At this time, if the interaction between the third traveling light standing wave 201c and the atoms is appropriately set (the beam waist, the wavelength, the light intensity, and the difference frequency between the opposing laser lights are appropriately set, respectively), an atomic beam 110c corresponding to the superposition state of |g, p0> and |g, p1> of each atom included in the intersection region between the atomic beam consisting of atoms in the state |g, p0> and the atomic beam consisting of atoms in the state |g, p1> is obtained. The traveling direction of the atomic beam 110c obtained after passing through the third traveling light standing wave 201c is theoretically either one or both of the direction of the zeroth order light and the direction based on the nth order Bragg condition.

[0044] When the Mach-Zehnder atom interferometer 500 is subjected to an angular velocity or acceleration in a plane including two paths of the atomic beam from the action of the first traveling light standing wave 201a to the action of the third traveling light standing wave 201c, a phase difference occurs between the two paths of the atomic beam from the action of the first traveling light standing wave 201a to the action of the third traveling light standing wave 201c, and this phase difference is reflected in the existence probability of the state |g, p0> and the existence probability of the state |g, p1> of each atom that has passed through the third traveling light standing wave 201c. Therefore, the observation device 400 can detect the angular velocity or acceleration by observing the atomic beam 110c from the interference device 250 (i.e., the atomic beam 110c obtained after passing through the third traveling light standing wave 201c). For example, the observation device 400 irradiates the atomic beam 110c from the interference device 250 with the probe light 408, and detects the fluorescence from the atoms in the state |g, p1> by the photodetector 409. Examples of the photodetector 409 include a photomultiplier tube and a fluorescent photodetector. In addition, according to this example, the spatial resolution is improved, that is, the distance between the two paths (atomic beams consisting of atoms in the state |g, p0> and atomic beams consisting of atoms in the state |g, p1>) after passing through the third traveling light standing wave is wide, so that a CCD image sensor can also be used as the photodetector 409. Alternatively, when a channeltron is used as the photodetector 409, the atomic beam of one of the two paths after passing through the third traveling light standing wave may be ionized by a laser or the like instead of the probe light, and the ions may be detected by the channeltron.

[0045] The atoms used in the Mach-Zehnder atom interferometer 500 are preferably alkaline earth metal atoms (calcium, strontium, barium, radium), alkaline earth-like metal atoms (atoms having an electron configuration that does not have a magnetic moment due to electron spin in the ground state, similar to alkaline earth metal atoms, and examples thereof include beryllium, magnesium, ytterbium, cadmium, and mercury), stable isotopes of alkaline earth metal atoms, or stable isotopes of alkaline earth-like metal atoms, on the premise that they have a metastable state as an energy eigenstate. Since these atoms have two electrons in their outermost shells, the sum of the spin angular momentum of antiparallel electrons becomes zero, and they are less susceptible to the influence of environmental magnetic fields. In particular, among alkaline earth metal atoms, alkaline earth-like metal atoms, stable isotopes of alkaline earth metal atoms, or stable isotopes of alkaline earth-like metal atoms, atoms that do not have a nuclear spin are preferable because they are not affected at all by environmental magnetic fields.

[0046] Since alkaline earth metal atoms, alkaline earth-like metal atoms, stable isotopes of alkaline earth metal atoms, and stable isotopes of alkaline earth-like metal atoms do not have a hyperfine structure, the output of the atom interferometer cannot be identified as the internal state of the atom. However, in this example, the spatial resolution of the output of the atom interferometer is greatly improved by using high-order Bragg diffraction, so the output of the atom interferometer can be visually recognized. In this case, if the orthogonal speed component of the atomic beam is large, the Bragg diffraction conditions of various orders are satisfied simultaneously, and the visibility of the atomic interference is reduced. Therefore, the above-mentioned collimator 700 is useful for the Mach-Zehnder type atom interferometer 500 that uses n-th order Bragg diffraction.

[0047] In the above-mentioned example of an atomic interferometer, Mach-Zehnder type atomic interference utilizing n-th order (n≧2) Bragg diffraction is used. However, the present invention is not limited to this type. For example, Mach-Zehnder type atomic interference utilizing a two-photon Raman process caused by a traveling optical standing wave may be used (see Reference 4). (Reference 4) TL Gustavson, P. Bouyer and MA Kasevich, “Precision Rotation Measurements with an Atom Interferometer Gyroscope,” Phys. Rev. Lett.78, 2046-2049, Published 17 March 1997.

[0048] In the above example of the atomic interferometer, Mach-Zehnder type atomic interference is used, which uses three traveling optical standing waves to perform one split, one inversion, and one mixing, but is not limited to this type, and for example, multi-stage Mach-Zehnder type atomic interference, which performs multiple splits, multiple inversions, and multiple mixing, may be used. For such multi-stage Mach-Zehnder type atomic interference, see Reference 5. (Reference 5) Takatoshi Aoki et al., “High-finesse atomic multiple-beam interferometer comprised of copropagating stimulated Raman-pulse fields,” Phys. Rev. A 63, 063611 (2001) Published 16 May 2001.

[0049] Furthermore, the atom interferometer to which the collimator of the present invention is applied is not limited to a Mach-Zehnder type atom interferometer, but may be, for example, a Ramsey-Bode type atom interferometer.

[0050] The atom interferometer of the present disclosure is not limited to the configuration shown in FIG. 5 that employs the quantum collimation technique of the present disclosure, and may have the following configuration C (see FIG. 6). Prior to the description of this configuration C, an atom interferometer (not shown) of the related art that combines prior art will be described. The atom interferometer of the related art includes an atomic beam source disclosed in Reference 6, an apparatus for adjusting the speed of atoms disclosed in Reference 7 or Reference 8, a collimation apparatus disclosed in the above-mentioned Patent Document 1, an interference apparatus 250, and a traveling light standing wave generating apparatus 350 (see FIG. 5 for the interference apparatus 250 and the traveling light standing wave generating apparatus 350). In the atom interferometer of the related art, the atomic beam from the atomic beam source disclosed in Reference 6 enters the apparatus for adjusting the speed of atoms disclosed in Reference 7 or Reference 8, and the width of the distribution of the atomic speed in the traveling direction of the atomic beam is reduced. If necessary, the path of the atomic beam is also adjusted by the apparatus for adjusting the speed of atoms disclosed in Reference 7 or Reference 8. The atomic beam from the device for adjusting the atomic speed disclosed in Reference 7 or Reference 8 enters the collimation device disclosed in Patent Document 1, and is physically collimated as described above. Configuration C (see FIG. 6) includes the quantum collimation device of the present disclosure instead of the collimation device disclosed in Patent Document 1. That is, configuration C includes the atomic beam source 180 disclosed in Reference 6, the device for adjusting the atomic speed 280 disclosed in Reference 7 or Reference 8, the collimator 700 of the present disclosure, the interference device 250, and the traveling light standing wave generating device 350. In the atom interferometer of the present disclosure having configuration C, the atomic beam from the atomic beam source 180 disclosed in Reference 6 enters the device for adjusting the atomic speed 280 disclosed in Reference 7 or Reference 8, and the width of the distribution of the atomic speed in the traveling direction of the atomic beam is reduced. If necessary, the path of the atomic beam is also adjusted by the atomic speed adjustment device 280 disclosed in Reference 7 or Reference 8. The atomic beam from the atomic speed adjustment device 280 disclosed in Reference 7 or Reference 8 enters the collimator 700 of the present disclosure and is quantum collimated as described above. (Reference 6) Japanese Patent No. 6650647 (Reference 7) Japanese Patent No. 6948655 (Reference 8) Japanese Patent No. 6948656

[0051] <Addendum 1> The technical features disclosed in the above-mentioned various embodiments and their modifications are not necessarily mutually exclusive. As long as there is no contradiction from a technical point of view, the technical features of one embodiment or its modifications may be applied to the technical features of another embodiment or its modifications.

[0052] The claims set forth in the claims section at the time of filing of this application do not necessarily exhaustively claim all inventions disclosed in this specification. In this regard, it should not be understood or interpreted that the applicant of this application has waived the right to obtain a patent for any invention not claimed at the time of filing of this application. To the extent permitted by the laws, regulations or treaties of the country or region in which this application is accepted, the applicant of this application reserves the right to obtain a patent for any invention not claimed in this application, the right to file a divisional application for such invention, the right to claim such invention by amendment, and any other rights, unless the applicant of this application expressly and conclusively expresses an intention to the contrary.

[0053] An example of a summary of the present disclosure based on another aspect is as follows:

[0054] A first aspect of the present invention is a method for quantum collimating an atomic beam, comprising the steps of: a first step of irradiating the atomic beam with a pumping laser beam having a wavelength corresponding to the transition between the ground state and the excited state of the atoms contained in the atomic beam, thereby causing the atoms to transition from the ground state to an excited state, and then relaxing from the excited state to a metastable state of the atoms; a second step of transitioning metastable atoms having a speed component equal to or smaller than a predetermined speed component Δv in the propagation direction of the filtered laser light to the ground state by irradiating the atomic beam with a filtered laser light having a wavelength corresponding to the transition between the ground state and the metastable state after the first step; has.

[0055] A second invention is a collimator for quantum collimating an atomic beam, comprising: an irradiation device configured to irradiate the atomic beam with a pumping laser light and a filtering laser light in this order; The pumping laser light is a laser light having a wavelength corresponding to the transition between the ground state and the excited state of the atoms in the atomic beam. The filtered laser light is laser light having a wavelength corresponding to the transition between the metastable state and the ground state that the excited atoms undergo during the relaxation process.

[0056] The third invention is the collimator of the second invention, The filtering laser beam is a Gaussian beam, and when Δv is a predetermined maximum value of the speed component in the propagation direction of the filtering laser beam of an atom that transitions from a metastable state to a ground state by passing the filtering laser beam, Δν is a transit-time broadening of an atom that does not have a speed component in the propagation direction of the filtering laser beam that crosses the filtering laser beam, α is a correction coefficient smaller than 1 that indicates that the linewidth of a spectral line of an atom that crosses the filtering laser beam and has a speed component in the propagation direction of the filtering laser beam is shortened by more than Δν, and k is the wave number of the filtering laser beam,

number

[0057] The fourth aspect of the present invention is the collimator of the third aspect of the present invention, α≒0.95 It is characterized by:

[0058] A fifth aspect of the present invention is a collimator according to any one of the second to fourth aspects of the present invention, The power density of the pumping laser light is greater than the saturation intensity of the transition between the ground state and the excited state, and W>v×E×N where W is the width of the pump laser light through which the atomic beam passes, v is the atomic speed component in the direction of atomic beam travel, N is the number of times that an atom needs to relax from an excited state to a metastable state with a given probability in the relaxation process, and E is the expected value of the time it takes for an excited atom to relax once. It is characterized by:

[0059] A sixth aspect of the present invention is a collimator according to any one of the second to fifth aspects of the present invention, The direction of the pumping laser light is not parallel to the direction of the filtering laser light. It is characterized by:

[0060] A seventh aspect of the present invention is an atom interferometer comprising: an atomic beam generating device for continuously generating an atomic beam; A traveling light standing wave generating device for generating three or more traveling light standing waves; An interference device for obtaining an atomic beam resulting from the interaction of an atomic beam with three or more traveling optical standing waves. Including, The atomic beam generator is An atomic beam source; Collimator and Including, The collimator is an irradiation device configured to irradiate the atomic beam with a pumping laser light and a filtering laser light in this order; The pumping laser light is a laser light having a wavelength corresponding to the transition between the ground state and the excited state of the atoms in the atomic beam. The filtered laser light is a laser light with a wavelength that corresponds to the transition between the metastable state and the ground state that the excited atoms undergo during the relaxation process. It is characterized by:

[0061] An eighth invention is an atomic gyroscope, an atomic beam generating device for continuously generating an atomic beam; A traveling light standing wave generating device for generating three or more traveling light standing waves; an interference device for obtaining an atomic beam resulting from interactions between the atomic beam and three or more traveling optical standing waves; An observation device that detects angular velocity or acceleration by observing the atomic beam from the interference device; Including, The atomic beam generator is An atomic beam source; Collimator and Including, The collimator is an irradiation device configured to irradiate the atomic beam with a pumping laser light and a filtering laser light in this order; The pumping laser light is a laser light having a wavelength corresponding to the transition between the ground state and the excited state of the atoms in the atomic beam. The filtered laser light is a laser light with a wavelength that corresponds to the transition between the metastable state and the ground state that the excited atoms undergo during the relaxation process. It is characterized by:

[0062] <Addendum 2> While the invention has been described with reference to exemplary embodiments, those skilled in the art will recognize that various changes can be made and elements thereof substituted with equivalents without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular system, device, or component thereof to the teachings of the invention without departing from the essential scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

[0063] Furthermore, the use of terms such as "first", "second", etc., does not indicate any order or importance, and terms such as "first", "second", etc., are used to distinguish elements. The terms used herein are for the purpose of describing the embodiments and are not intended to limit the invention in any way. The term "comprises" and its conjugations, when used in this specification and / or the appended claims, discloses the presence of the mentioned features, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The term "and / or" includes any and all combinations of one or more of the associated listed elements, if any. In the claims and the specification, unless otherwise stated, the terms "connected", "coupled", "joined", "connected", or synonyms thereof, and all forms thereof, do not necessarily negate the presence of one or more intermediate elements between two elements that are, for example, "connected" or "coupled" to each other or "connected" to each other. In the claims and the specification, the term "optional", if any, unless otherwise stated, should be understood as a term that represents the same meaning as the universal symbol ∀. For example, "for any X" has the same meaning as "for all X" or "for each X."

[0064] Unless otherwise specified, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. Furthermore, terms such as those defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant art and this disclosure, and should not be interpreted ideally or excessively formally unless explicitly defined.

[0065] It will be understood that in the description of the present invention, many techniques and steps are disclosed. Each of these has separate advantages and each can be used in combination with one or more, or in some cases all, of the other disclosed techniques. Thus, to avoid cluttering, this specification refrains from describing every possible combination of individual techniques or steps. Nevertheless, the specification and claims should be read with the understanding that such combinations are fully within the scope of the present invention and claims.

[0066] The corresponding structures, materials, acts, and equivalents of all functional elements combined with means or steps in the following claims are intended to include the structures, materials, or acts, if any, for performing the function in combination with other elements.

[0067] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Various modifications and variations are permitted within the scope of the present invention. The selected and described embodiments are intended to illustrate the principles of the present invention and its practical application. The present invention is used in various embodiments with various modifications and variations, and the various modifications and variations are determined according to the expected use. All such modifications and variations are intended to be included within the scope of the present invention as defined by the appended claims, and are intended to be accorded the same protection when interpreted in accordance with the breadth that is fairly, legally and equitably entitled thereto. [Explanation of symbols]

[0068] 100 Atomic radiation source 100a heater 100b Nozzle 110 Atomic beam 110a Atomic beam 110b Focused atomic beam 110c atomic beam 200 Vacuum container 201a Traveling light standing wave 201b Traveling light standing wave 201c Traveling light standing wave 250 Interference Device 350 Traveling light standing wave generator 400 Observation Equipment 500 Atom Interferometer 600 Atomic Gyroscope 700 Collimator 701a Pumping laser light 701b Filtering laser light 710 Irradiation device 721 Laser Light Source 722 Laser Light Source 740 Lens

Claims

1. 1. A method for quantum collimating an atomic beam, comprising: a first step of irradiating the atomic beam with a pumping laser beam having a wavelength corresponding to a transition between a ground state and an excited state of atoms contained in the atomic beam, thereby causing the atoms to transition from the ground state to the excited state and further relaxing from the excited state to a metastable state of the atoms; a second step of, after the first step, transitioning the atoms in the metastable state, which have a speed component equal to or smaller than a predetermined speed component Δv in the propagation direction of the filtered laser light, to the ground state by irradiating the atomic beam with a filtered laser light having a wavelength corresponding to a transition between the ground state and the metastable state; The method according to claim 1,

2. 1. A collimator for quantum collimating an atomic beam, comprising: an irradiation device configured to irradiate the atomic beam with a pumping laser beam and a filtering laser beam in this order; the pumping laser light is a laser light having a wavelength corresponding to a transition between a ground state and an excited state of atoms contained in the atomic beam, The filtered laser light is a laser light having a wavelength corresponding to a transition between a metastable state and the ground state, which the excited atoms undergo during a relaxation process. Collimator.

3. 3. The collimator according to claim 2, the filtered laser light is a Gaussian beam; Let Δv be a predetermined maximum value of a speed component in the propagation direction of the filtering laser beam of the atom that transitions from the metastable state to the ground state as a result of the atomic beam passing through the filtering laser beam, let Δν be a transit-time broadening of an atom that crosses the filtering laser beam and does not have a speed component in the propagation direction of the filtering laser beam, let α be a correction coefficient smaller than 1 that indicates that the linewidth of a spectral line of an atom that crosses the filtering laser beam and has a speed component in the propagation direction of the filtering laser beam is shortened by more than Δν, and let k be the wave number of the filtering laser beam. [0050] holds true A collimator characterized by:

4. 4. The collimator according to claim 3, α≒0.95 A collimator characterized by:

5. 3. The collimator according to claim 2, the power density of the pumping laser light is greater than the saturation intensity of the transition between the ground state and the excited state; and W>v x E x N where W is the width of the pumping laser light through which the atomic beam passes, v is the speed component of the atoms in the direction of travel of the atomic beam, N is the number of times of relaxation required for the atoms to relax from the excited state to the metastable state with a predetermined probability in the relaxation process, and E is the expected value of the time required for the atoms in the excited state to relax once. A collimator characterized by:

6. 3. The collimator according to claim 2, The propagation direction of the pumping laser beam is not parallel to the propagation direction of the filtering laser beam. A collimator characterized by:

7. 1. An atom interferometer comprising: an atomic beam generating device for continuously generating an atomic beam; A traveling light standing wave generating device for generating three or more traveling light standing waves; an interference device for obtaining an atomic beam resulting from the interaction between the atomic beam and the three or more traveling optical standing waves; Including, The atom beam generating device includes: An atomic beam source; Collimator and Including, The collimator comprises: an irradiation device configured to irradiate the atomic beam with a pumping laser beam and a filtering laser beam in this order; the pumping laser light is a laser light having a wavelength corresponding to a transition between a ground state and an excited state of atoms contained in the atomic beam, The filtered laser light is a laser light having a wavelength corresponding to a transition between a metastable state and the ground state, which the excited atoms undergo during a relaxation process.

1. An atom interferometer comprising:

8. 1. An atomic gyroscope, comprising: an atomic beam generating device for continuously generating an atomic beam; A traveling light standing wave generating device for generating three or more traveling light standing waves; an interference device for obtaining an atomic beam resulting from the interaction between the atomic beam and the three or more traveling optical standing waves; an observation device that detects angular velocity or acceleration by observing the atomic beam from the interference device; Including, The atom beam generating device includes: An atomic beam source; Collimator and Including, The collimator comprises: an irradiation device configured to irradiate the atomic beam with a pumping laser beam and a filtering laser beam in this order; the pumping laser light is a laser light having a wavelength corresponding to a transition between a ground state and an excited state of atoms contained in the atomic beam, The filtered laser light is a laser light having a wavelength corresponding to a transition between a metastable state and the ground state, which the excited atoms undergo during a relaxation process. An atomic gyroscope characterized by:

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