Quantum device and method for manufacturing quantum device

Abstract

A quantum device of the present invention has: a first waveguide; an optical resonator connected to the first waveguide; a first light source that introduces first light into the first waveguide; and a second light source that radiates second light onto the optical resonator. The optical resonator has a second waveguide extending in a first direction, and a color center provided to the second waveguide. The second light source has an optical axis in a second direction orthogonal to the first direction, and the color center is irradiated with the second light.

Description

Quantum device and method for manufacturing the same

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to quantum devices and methods for manufacturing quantum devices.

[0002] In recent years, research and development into quantum computers has been vigorously pursued. For example, quantum computers that use the electron spin levels of color centers in diamonds as quantum bits are known. In such quantum computers, electron spin information is converted into photon information, which is then optically read.

[0003] JP 2014-216596 A International Publication No. 2020 / 203746

[0004] Kazuki Koshino and three others, "Deterministic quantum state switching by a single photon," Journal of the Physical Society of Japan, Vol. 1, No. 1, 2014

[0005] The optical transitions used to read out the states occur probabilistically based on the selection rules of quantum mechanics, making it difficult for quantum devices used in conventional quantum computers to efficiently convert electron spin information into photon information.

[0006] An object of the present disclosure is to provide a quantum device and a method for manufacturing the quantum device that can improve the efficiency of converting electron spin information into photon information.

[0007] According to one aspect of the present disclosure, there is provided a quantum device comprising: a first waveguide; an optical resonator connected to the first waveguide; a first light source that introduces first light into the first waveguide; and a second light source that irradiates second light onto the optical resonator, wherein the optical resonator has a second waveguide extending in a first direction and a color center provided in the second waveguide, the second light source has an optical axis in a second direction perpendicular to the first direction, and the second light is irradiated onto the color center.

[0008] According to the present disclosure, it is possible to improve the efficiency of converting electron spin information into photon information.

[0009] FIG. 1 is a plan view showing a quantum device according to a first embodiment. FIG. 2 is a cross-sectional view showing a quantum device according to the first embodiment. FIG. 3 is a diagram showing an example of the operation of the quantum device according to the first embodiment. FIG. 4 is a diagram showing another example of the operation of the quantum device according to the first embodiment. FIG. 5 is a diagram showing the operation of the quantum device according to the first embodiment, in which a parameter (Ω ｄ / χ) and γ ｍｎ / γ (m is 3 or 4, n is 1 or 2). FIG. 6 is a perspective view (part 1) showing a method for manufacturing an optical resonator in a quantum device according to the first embodiment. FIG. 7 is a perspective view (part 2) showing a method for manufacturing an optical resonator in a quantum device according to the first embodiment. FIG. 8 is a perspective view (part 3) showing a method for manufacturing an optical resonator in a quantum device according to the first embodiment. FIG. 9 is a perspective view (part 4) showing a method for manufacturing an optical resonator in a quantum device according to the first embodiment. FIG. 10 is a perspective view (part 5) showing a method for manufacturing an optical resonator in a quantum device according to the first embodiment. FIG. 11 is a diagram showing the calculation results of the electromagnetic field distribution for the first embodiment. FIG. 12 is a diagram showing the intensity profile of a standing wave extracted near the color center. FIG. 13 is a plan view showing a quantum device according to the second embodiment. FIG. 14 is a plan view showing a quantum device according to the third embodiment. FIG. 15 is a diagram showing a quantum processing apparatus according to the fourth embodiment.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that in this specification and drawings, components having substantially the same functional configurations may be denoted by the same reference numerals to avoid redundant description. In this disclosure, the X1-X2 direction, the Y1-Y2 direction, and the Z1-Z2 direction are defined as mutually orthogonal directions. A plane including the X1-X2 direction and the Y1-Y2 direction will be referred to as the XY plane, a plane including the Y1-Y2 direction and the Z1-Z2 direction will be referred to as the YZ plane, and a plane including the Z1-Z2 direction and the X1-X2 direction will be referred to as the ZX plane. For convenience, the Z1-Z2 direction will be defined as the up-down direction, with the Z1 side referred to as the upper side and the Z2 side referred to as the lower side. Furthermore, a planar view refers to viewing an object from the Z1 side, and a planar shape refers to the shape of an object viewed from the Z1 side.

[0011] (First Embodiment) A first embodiment will be described. Fig. 1 is a plan view showing a quantum device according to the first embodiment. Fig. 2 is a cross-sectional view showing the quantum device according to the first embodiment. Fig. 2 corresponds to a cross-sectional view taken along line II in Fig. 1.

[0012] The quantum device 1 according to the first embodiment mainly includes a first waveguide 100, an optical resonator 200, a first light source 10, a second light source 20, a static magnetic field source 30, and a microwave source 40. The second light source 20 is provided on a printed wiring board 91, the static magnetic field source 30 is provided on a printed wiring board 92, and the microwave source 40 is provided on a printed wiring board 93.

[0013] The printed wiring board 92 is provided on the printed wiring board 91, and the printed wiring board 93 is provided on the printed wiring board 92. The static magnetic field source 30 is located on the second light source 20, and the microwave source 40 is located on the static magnetic field source 30. The second light source 20, the static magnetic field source 30, and the microwave source 40 overlap in the Z1-Z2 direction. The second light source 20 has an optical axis 29 in the Z1-Z2 direction. The second light source 20 is, for example, a coherent light source. The Z1-Z2 direction is an example of the second direction. Note that the stacking order between the printed wiring boards 91, 92, and 93 is not limited to that described above.

[0014] A substrate 50 is provided on the printed wiring board 93, and a first waveguide 100 and an optical resonator 200 are provided on the substrate 50. The substrate 50 supports the first waveguide 100 and the optical resonator 200. The refractive index of the material of the substrate 50 is lower than that of diamond. For example, the material of the substrate 50 is silicon oxide (SiO ２ ) or sapphire.

[0015] The optical resonator 200 has a second waveguide 210 extending in the X1-X2 direction. The second waveguide 210 includes diamond having a color center 220. For example, the second waveguide 210 is composed of diamond having the color center 220. The color center 220 is provided at the end of the second waveguide 210 on the X2 side. For example, the color center 220 is provided at a position several tens of nanometers away from the end face of the second waveguide 210 on the X2 side toward the X1 side. The color center 220 is on the optical axis 29. Therefore, the second light 22 emitted by the second light source 20 is irradiated onto the color center 220. The color center 220 is, for example, a nitrogen-vacancy center (NV center) composed of nitrogen and vacancies. The color center 220 may be a silicon-vacancy center (SiV center) composed of silicon and vacancies, a germanium-vacancy center (GeV center) composed of germanium and vacancies, a tin-vacancy center (SnV center) composed of tin and vacancies, a lead-vacancy center (PbV center) composed of lead and vacancies, or a boron-vacancy center (BV center) composed of boron and vacancies. The substrate 50 is an example of a support. The X1-X2 direction is an example of a first direction.

[0016] The second waveguide 210 has a plurality of openings 211 formed at equal intervals in the X1-X2 direction. The openings 211 penetrate the second waveguide 210 in the Z1-Z2 direction. The openings 211 function as mirrors. The optical resonator 200 also has a reflective film 230 that covers the end face on the X2 side of the second waveguide 210. The reflective film 230 is a metal film that has a high reflectivity for visible light. The reflective film 230 is, for example, an Ag film with a thickness of approximately several tens of nanometers. The reflective film 230 suppresses emission of light from the end face on the X2 side of the optical resonator 200.

[0017] The first waveguide 100 is connected to the end of the second waveguide 210 on the X1 side. The first waveguide 100 extends in the X1-X2 direction. The first waveguide 100 includes a nitride semiconductor, such as AlN, which has a lower refractive index and a lower absorption rate in the visible light range than diamond. For example, the first waveguide 100 is made of AlN. The first light source 10 irradiates the first waveguide 100 with a first light 11. The first light source 10 is, for example, a quantum light source.

[0018] In this embodiment, the following relationship holds: The coupling coefficient g of the optical resonator 200 is proportional to the resonant frequency ω of the optical resonator 200. ｃ and the light emission frequency ω of the color center 220 ａ The absolute value of the difference between ｃ -ω ａ The frequency ω of the second light 22 is smaller than | ｄ ω ａ is equal to -2χ, where χ is g ２ / (ω ｃ -ω ａ )

[0019] Next, the operation of the quantum device 1 according to the first embodiment will be described. Fig. 3 is a diagram showing an example of the operation of the quantum device 1 according to the first embodiment. Fig. 4 is a diagram showing another example of the operation of the quantum device 1 according to the first embodiment.

[0020] In the quantum device 1, first light 11 is introduced from the first light source 10 into the first waveguide 100, where it reaches the color center 220. The color center 220 forms an energetically discrete spin level (spin triplet) within the band gap at a frequency on the order of GHz, corresponding to its own spin quantum number of 1. If the spin levels with spin magnetic quantum numbers 0 and -1 are considered quantum bits, the spin 0 state exhibits a light absorption-emission process between the ground and excited levels in the visible light range, i.e., a luminescent relaxation process. On the other hand, the spin -1 state exhibits a non-luminescent relaxation process to the ground level of spin 0 via a metastable state of spin 0 (spin singlet). In other words, after microwave manipulation of the quantum bit level, the quantum bit can be read out via photons (spin-to-photon conversion) by measuring the photon information (presence or absence of photon emission) emitted after optical excitation within the timescale in which the state coherence is maintained.

[0021] Furthermore, regarding the transition between the ground and excited levels for luminescence relaxation, based on the Jaynes-Cummings model, two two-level systems are formed, represented by four levels: |g,0>, |g,1>, |e,0>, and |e,1>. Here, g indicates the ground level for luminescence relaxation, e indicates the excited level for luminescence relaxation, and 0 or 1 indicates the number of photons in the optical resonator 200. These two two-level systems form dressed levels consisting of four levels: |1>, |2>, |3>, and |4>, as shown in FIGS. 3 and 4 , by the second light 22 (external control light). The two levels |1> and |2> are the levels of the color center 220 itself, and |3> and |4> are levels formed by irradiation with the second light 22. Here, the relaxation rate from the |4> level to the |1> level is defined as γ ４１ The relaxation rate from the level |4> to the level |2> is γ ４２ The relaxation rate from the level |3> to the level |1> is γ ３１ The relaxation rate from the level |3> to the level |2> is γ ３２ In this case, γ = γ ３１ +γ ３２ = γ ４１ +γ ４２ The intensity of the second light 22 is Ω ｄ Then, γ ３１ , γ ３２ , γ ４１ and γ ４２ is expressed as follows:

[0022] gamma ３２ / γ = γ ４１ / γ=cos ２ (tan －１ (2 ohms ｄ / χ)) γ ３１ / γ = γ ４２ / γ=sin ２ (tan －１ (2 ohms ｄ / χ))

[0023] Figure 5 shows the parameter (Ω ｄ / χ) and γ ｍｎ / γ (m is 3 or 4, n is 1 or 2). Here, the color center 220 is assumed to be an NV center, and ω ａ = 2.959 x 10 １５rad / s (637 nm), ω ｃ =ω ａ +10 １０ (1.6GHz), g=10 １０ rad / s, χ=10 ６ rad / s, Ω ｄ = 5 x 10 ５ rad / s, γ=2.4×10 ３ rad / s. 637 nm is the emission frequency ω of the color center. ａ is the wavelength corresponding to Ω and 1.6 GHz is the frequency of the resonator. ｄ / χ) is 0.5, ３１ / γ, γ ３２ / γ, γ ４１ / γ and γ ４２ / γ is equal. In other words, the parameter (Ω ｄ / χ) is 0.5, at least the relaxation rate γ ３１ and relaxation rate γ ３２ and the relaxation rate γ ４１ and relaxation rate γ ４２ Furthermore, the coupling coefficient g and the volume gω of the optical resonator 200 are equal to each other. ｃ V ｍ Considering this, (2g ２ / kγ)×(4π ２ / 3λ ３ ) × V ｍ The Q value expressed as follows is approximately 500. This indicates that highly efficient spin-to-photon conversion is possible. Ultimately, on-demand (deterministic) optical spin-to-photon conversion may also be possible. Note that k and λ are the relaxation rate and resonant wavelength of the cavity, respectively.

[0024] In this embodiment, in the example shown in FIG. 3 , the |3> level is not used, but rather the three levels |1>, |2>, and |4> are used to focus on a Λ-type three-level system, and spin-photon conversion is performed. Also, in the example shown in FIG. 4 , the |4> level is not used, but rather the three levels |1>, |2>, and |3> are used to focus on a Λ-type three-level system, and spin-photon conversion is performed. During spin-photon conversion, the static magnetic field source 30 generates a static magnetic field that reaches the color center 220, and the microwave source 40 generates microwaves that reach the color center 220. The optical resonator 200 outputs third light 13 (inelastically scattered light) having a wavelength different from that of the first light 11 to the first waveguide 100. By observing this third light 13, the state of the color center 220 can be grasped.

[0025] As described above, in the first embodiment, of the spin levels constituting the quantum bit in the color center 220, one of the transitions between the ground level and the excited level that relaxes the luminescence in response to the first light 11 (readout light) introduced into the color center 220 is coupled to the optical resonator 200. Furthermore, the relaxation rate of the three-level system formed by the application of the second light 22 (external control light) is controlled. As a result, the two relaxation rates from the excited level to the ground level of the three-level system become equal, thereby improving the efficiency of spin-to-photon conversion. In other words, the efficiency of converting electron spin information into photon information can be improved.

[0026] Next, we will explain a method for manufacturing the optical resonator 200. Figures 6 to 10 are perspective views showing a method for manufacturing the optical resonator 200 in the quantum device 1 according to the first embodiment.

[0027] 6, a thin diamond substrate 210A is prepared as the base material for the second waveguide 210, and the diamond substrate 210A is cleaned. Next, a desired element species, such as nitrogen, is implanted by ion implantation or the like, and annealing (activation treatment) is performed to form the color center 220.

[0028] Thereafter, as shown in FIG. 7, a diamond substrate 210B having dimensions closer to those of the second waveguide 210 than those of the diamond substrate 210A is obtained by processing using a focused ion beam (FIB) method or the like and forming an opening 211.

[0029] Subsequently, as shown in FIG. 8, a reflective film 230 is formed by vapor deposition or the like so as to cover the end face on the X2 side of the diamond substrate 210B.

[0030] Next, as shown in FIG. 9, the diamond substrate 210B is processed by FIB or the like to obtain the second waveguide 210.

[0031] 10, the second waveguide 210 is bonded onto the substrate 50. For example, the first waveguide 100 is formed on the substrate 50 in advance.

[0032] In this manner, the optical resonator 200 can be manufactured.

[0033] When manufacturing the quantum device 1, a printed wiring board 91 equipped with the second light source 20, a printed wiring board 92 equipped with the static magnetic field source 30, and a printed wiring board 93 equipped with the microwave source 40 are stacked together. Then, a substrate 50 (see FIG. 10 ) equipped with the first waveguide 100 and the optical resonator 200 is provided on the printed wiring board 93. The first light source 10 may be connected to the first waveguide 100 in advance, or the substrate 50 may be provided on the printed wiring board 93 and then connected to the first waveguide 100.

[0034] Here, we will explain the calculation results of the electromagnetic field distribution related to the first embodiment. In this calculation, we assumed that the color center 220 was an NV center and obtained the electromagnetic field distribution within the optical resonator 200 under the following dimensions (structural parameters):

[0035] The distance between the X2-side end face of the second waveguide 210 and the color center 220 is 25 nm. The reflective film 230 is an Ag film with a thickness of 10 nm. The diameter of the openings 211 is 100 nm. The pitch of the openings 211 is 200 nm. The length (dimension in the X1-X2 direction) of the second waveguide 210 is 2000 nm. The width (dimension in the Y1-Y2 direction) of the second waveguide 210 is 280 nm. The height (dimension in the Z1-Z2 direction) of the second waveguide 210 is 120 nm.

[0036] FIG. 11 shows the calculation results of the electromagnetic field distribution for the first embodiment. The electromagnetic field intensity is normalized. The horizontal axis in FIG. 11 indicates the position based on the X1-side end face of the optical resonator 200, with the X2 side being positive. The vertical axis in FIG. 11 indicates the position based on the center of the optical resonator 200 in the Y1-Y2 direction, with the Y1 side being positive. As shown in FIG. 11, the reflective film 230 suppresses energy emission toward the X2 side relative to the reflective film 230. Furthermore, a standing wave with a relatively high electromagnetic field intensity is formed at the position of the color center 220. FIG. 12 shows the intensity profile of the standing wave extracted near the color center 220. The Q value of the optical resonator 200 estimated from the intensity profile shown in FIG. 12 is 520. This indicates highly efficient spin-to-photon conversion. Generally, a Q value of approximately 500 enables on-demand (deterministic) photon generation. Therefore, the calculation results of this electromagnetic field distribution suggest that the quantum device 1 according to the first embodiment is capable of generating photons on demand (deterministically).

[0037] Second Embodiment A second embodiment will now be described. Fig. 13 is a plan view showing a quantum device according to the second embodiment.

[0038] The quantum device 2 according to the second embodiment has an optical resonator 300 instead of the optical resonator 200. The optical resonator 300 has a second waveguide 310 extending in the X1-X2 direction, and a ring resonator 340.

[0039] The second waveguide 310, like the second waveguide 210, includes diamond having a color center 320. For example, the second waveguide 310 is composed of diamond having a color center 320. The color center 320 is provided at the end of the second waveguide 310 on the X2 side. For example, the color center 320 is provided at a position several tens of nanometers away from the end face of the second waveguide 310 on the X1 side. Like the color center 220, the color center 320 is on the optical axis 29 (see FIG. 2). Therefore, the second light 22 emitted by the second light source 20 is irradiated onto the color center 320. The color center 320 is, for example, an NV center, SiV center, GeV center, SnV center, PbV center, or BV center. Unlike the second waveguide 210, the second waveguide 310 does not have an opening formed therein.

[0040] The ring resonator 340 includes diamond. For example, the ring resonator 340 is made of diamond. The ring resonator 340 is coupled to the portion of the second waveguide 310 where the color center 320 is provided.

[0041] The other configurations are the same as those of the first embodiment.

[0042] In the second embodiment, the electromagnetic field distribution of the eigenmode in the ring resonator 340 is reflected in the second waveguide 310, and the electromagnetic field intensity increases near the color center 320. This enhances the interaction between the color center 320 and the electromagnetic field. In other words, the absorption and emission of light by the color center 320 are enhanced. Similarly to the first embodiment, the second embodiment also improves the efficiency of converting electron spin information into photon information.

[0043] Third Embodiment A third embodiment will now be described. Fig. 14 is a plan view showing a quantum device according to the third embodiment.

[0044] The quantum device 3 according to the third embodiment has an optical resonator 400 instead of the optical resonator 200. The optical resonator 400 has a second waveguide 410 extending in the X1-X2 direction and a third waveguide 450 extending in the Y1-Y2 direction.

[0045] The second waveguide 410, like the second waveguide 210, includes diamond having a color center 420. For example, the second waveguide 410 is composed of diamond having a color center 420. The color center 420 is provided at the end of the second waveguide 410 on the X2 side. For example, the color center 420 is provided at a position several tens of nanometers away from the end face of the second waveguide 410 on the X1 side. Like the color center 220, the color center 420 is on the optical axis 29 (see FIG. 2). Therefore, the second light 22 emitted by the second light source 20 is irradiated onto the color center 420. The color center 420 is, for example, an NV center, SiV center, GeV center, SnV center, PbV center, or BV center. Unlike the second waveguide 210, the second waveguide 410 does not have an opening formed therein.

[0046] The third waveguide 450 includes diamond. For example, the third waveguide 450 is made of diamond. The third waveguide 450 is perpendicular to the second waveguide 410 in a T-shape. The third waveguide 450 has a portion extending from the intersection with the second waveguide 410 to the Y1 side and a portion extending to the Y2 side. The color center 420 may also be included in the third waveguide 450. The third waveguide 450 has a plurality of openings 451 formed at equal intervals in the Z1-Z2 direction. The openings 451 penetrate the third waveguide 450 in the Z1-Z2 direction. The openings 451 function as a mirror.

[0047] The other configurations are the same as those of the first embodiment.

[0048] In the third embodiment, the electromagnetic field distribution of the eigenmode in the third waveguide 450 is reflected in the second waveguide 410, and the electromagnetic field intensity increases near the color center 420. This enhances the interaction between the color center 420 and the electromagnetic field. In other words, the absorption and emission of light by the color center 420 are enhanced. Similarly to the first embodiment, the third embodiment also improves the efficiency of converting electron spin information into photon information.

[0049] Fourth Embodiment A fourth embodiment will now be described. Fig. 15 is a diagram showing a quantum processing device according to the fourth embodiment.

[0050] The quantum processing device 4 according to the fourth embodiment includes one beam splitter 67, two detectors 68, two wavelength filters 66, and two multiplexers 65. One end of four waveguides 73 is connected to each multiplexer 65, and a half mirror 64 is provided at the other end of the waveguide 73, and one end of a waveguide 72 is connected to the half mirror 64. A waveguide 71 is connected to the other end of the waveguide 72 in a T-shape. A first light source 61 is connected to one end of the waveguide 71, and an optical resonator 62 is connected to the other end. A dielectric mirror 63 is provided at the intersection of the waveguide 71 and the waveguide 72. The first light source 61 may be, for example, the first light source 10. The optical resonator 62 may be, for example, the optical resonator 200, 300, or 400. Although not shown, similarly to the first, second or third embodiment, a second light source 20, a static magnetic field source 30 and a microwave source 40 are provided below the optical resonator 62. As the waveguide 71, for example, a first waveguide 100 is used.

[0051] In this way, in the fourth embodiment, the structures of the first, second or third embodiment are arranged in parallel.

[0052] In one quantum bit operation, after the state of the color center (quantum bit) is manipulated by microwaves, a first light (readout light) is incident on the optical resonator 62 via the dielectric mirror 63. A second light source irradiates the color center with a second light. The first light is reflected by the optical resonator 62, and a third light (photon) is output. The third light (photon) is reflected by the dielectric mirror 63 toward the waveguide 72, passes through the half mirror 64, the waveguide 73, the combiner 65, the wavelength filter 66, and the beam splitter 67, and is detected by the detector 68.

[0053] In two-qubit operations, the third light (photon) output from one multiplexer 65 and the third light (photon) output from the other multiplexer 65 are correlated by the beam splitter 67. By observing the two photons with a detector, an entangled state between the quantum bits can be formed via the photons.

[0054] In this way, the combination of one-qubit arbitrary gate operation and two-qubit gate operation enables universal quantum operations. Therefore, according to this embodiment, a general-purpose quantum computer using diamond color centers can be constructed.

[0055] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0056] 1, 2, 3: quantum device 4: quantum processing unit 10, 61: first light source 11: first light 13: third light 20: second light source 22: second light 29: optical axis 30: static magnetic field source 40: microwave source 50: substrate 62, 200, 300, 400: optical resonator 71, 72, 73: waveguide 100: first waveguide 210, 310, 410: second waveguide 211, 451: opening 220, 320, 420: color center 230: reflective film 340: ring resonator 450: third waveguide

Claims

1. A first waveguide; and an optical resonator connected to the first waveguide; a first light source that introduces a first light into the first waveguide; a second light source that irradiates the optical resonator with a second light; having the optical resonator has a second waveguide extending in a first direction and a color center provided in the second waveguide; The second light source has an optical axis in a second direction perpendicular to the first direction, A quantum device, characterized in that the second light is irradiated onto the color center.

2. The quantum device according to claim 1 , wherein a third light having a wavelength different from that of the first light is output from the optical resonator to the first waveguide.

3. the color center is provided at one end of the second waveguide; 2. The quantum device of claim 1, wherein the first waveguide is connected to the other end of the second waveguide.

4. a static magnetic field source that generates a magnetic field that extends to the color center; a microwave source that generates microwaves that reach the color center; 3. The quantum device according to claim 1, further comprising:

5. 3. The quantum device according to claim 1, wherein the color center includes a complex defect of N, Si, Ge, Sn, Pb, or any combination thereof, and a vacancy.

6. 3. The quantum device according to claim 1, wherein the material of the second waveguide is diamond, and the refractive index of the material of the first waveguide is lower than the refractive index of diamond.

7. the first light source is a quantum light source; 3. The quantum device according to claim 1, wherein the second light source is a coherent light source.

8. 3. The quantum device according to claim 1, wherein the second waveguide has a plurality of openings arranged at equal intervals in the first direction.

9. 3. The quantum device according to claim 1, wherein a coupling coefficient of the optical resonator is smaller than an absolute value of a difference between a resonance frequency of the optical resonator and an emission frequency of the color center.

10. the first light source is a coherent light source; The light intensity of the second light source is Ωd, the coupling coefficient of the optical resonator is g, and the resonance frequency of the optical resonator is ω ｃ , the emission frequency of the color center is ω ａ , then, χ = g ２ / (ω ｃ - ω ａ ), and አማርስ ２ (tan) －１ (2Ω) ｄ / x))=sin ２ (tan) －１ (2Ω) ｄ / x)) 3. The quantum device according to claim 1, wherein the following holds true:

11. The frequency of the second light is ω ａ Quantum device according to claim 10, characterized in that it is equal to -2χ.

12. providing an optical resonator coupled to a first waveguide; providing a first light source that introduces a first light into the first waveguide; providing a second light source that irradiates the optical resonator with a second light; having the optical resonator has a second waveguide extending in a first direction and a color center provided in the second waveguide; The second light source has an optical axis in a second direction perpendicular to the first direction, and is positioned so that the second light is irradiated onto the color center.