Quantum device and method for manufacturing quantum device

Abstract

This quantum device includes: a first surface; a waveguide extending in a first direction parallel to the first surface; a plurality of nano-pillars connected to the first surface and arranged in the first direction; colour centres respectively formed on the plurality of nano-pillars; and a pair of electrodes provided to each colour centre. The plurality of nano-pillars are each inclined from the first direction and extend in a second direction inclined from the normal direction of the first surface. An electric field is applied from the pair of electrodes to the colour centre.

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] US Patent Application Publication No. 2011 / 0309265 US Patent Application Publication No. 2012 / 0161663 JP Patent Publication No. 2015-529328 JP Patent Publication No. 2007-526639

[0004] CT Nguyen et al., Phys. Rev. Lett. 123, 183602, (2019)A. Sipahigil et al., Science 354, 847 (2016)Ph. Tamarat et al., PHYSICAL REVIEW LETTERS 97, 083002 (2006)LD Santis et al., PHYSICAL REVIEW LETTERS 127, 147402 (2021) J. Lisenfeld npj Quantum Information (2019) 5:105

[0005] A quantum computer includes multiple quantum bits. To ensure the indistinguishability of photons, which is necessary for forming entanglement between multiple quantum bits during computation, it is desirable for the emission wavelengths of color centers to match. However, the emission wavelengths of color centers differ by an order of GHz when converted to frequency due to defects or distortions around the color centers. Although techniques for adjusting the emission wavelengths of color centers have been proposed, it is difficult to arrange multiple quantum bits with a high degree of integration.

[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 integration density of quantum bits.

[0007] According to one aspect of the present disclosure, there is provided a quantum device comprising: a waveguide having a first surface and extending in a first direction parallel to the first surface; a plurality of nanopillars connected to the first surface and aligned in the first direction; a color center formed in each of the plurality of nanopillars; and an electrode pair provided for each of the color centers, wherein each of the plurality of nanopillars is inclined from the first direction and extends in a second direction inclined from the normal direction of the first surface, and an electric field is applied to the color center from the electrode pair.

[0008] According to the present disclosure, the integration density of quantum bits can be improved.

[0009] FIG. 1 is a perspective view of a quantum device according to the first embodiment. FIG. 2 is a plan view of a quantum device according to the first embodiment. FIG. 3 is a cross-sectional view of a quantum device according to the first embodiment. FIG. 4 is a cross-sectional view (part 1) illustrating a method for manufacturing a quantum device according to the first embodiment. FIG. 5 is a cross-sectional view (part 2) illustrating a method for manufacturing a quantum device according to the first embodiment. FIG. 6 is a cross-sectional view (part 3) illustrating a method for manufacturing a quantum device according to the first embodiment. FIG. 7 is a cross-sectional view (part 4) illustrating a method for manufacturing a quantum device according to the first embodiment. FIG. 8 is a cross-sectional view (part 5) illustrating a method for manufacturing a quantum device according to the first embodiment. FIG. 9 is a cross-sectional view (part 6) illustrating a method for manufacturing a quantum device according to the first embodiment. FIG. 10 is a cross-sectional view (part 7) illustrating a method for manufacturing a quantum device according to the first embodiment. FIG. 11 is a cross-sectional view (part 8) illustrating a method for manufacturing a quantum device according to the first embodiment. FIG. 12 is a plan view (part 1) illustrating a method for manufacturing a quantum device according to the first embodiment. FIG. 13 is a plan view (part 2) showing a method for manufacturing a quantum device according to the first embodiment. FIG. 14 is a plan view (part 3) showing a method for manufacturing a quantum device according to the first embodiment. FIG. 15 is a plan view (part 4) showing a method for manufacturing a quantum device according to the first embodiment. FIG. 16 is a top view showing an example of a method for using a quantum device according to the first embodiment. FIG. 17 is a cross-sectional view showing an example of a method for using a quantum device according to the first embodiment. FIG. 18 is a diagram (part 1) showing the relationship between electric field strength F and the amount of change ΔE in optical transition frequency. FIG. 19 is a diagram (part 2) showing the relationship between electric field strength F and the amount of change ΔE in optical transition frequency. FIG. 20 is a diagram showing the relationship between wavelength and transmittance for various metals. FIG. 21 is a diagram showing a quantum processing device according to a second 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 perspective view showing a quantum device according to the first embodiment. Fig. 2 is a plan view showing the quantum device according to the first embodiment. Fig. 3 is a cross-sectional view showing the quantum device according to the first embodiment. Fig. 3 corresponds to a cross-sectional view taken along line III-III in Fig. 2.

[0012] The quantum device 1 according to the first embodiment mainly includes a slab waveguide 10 , a plurality of nanopillars 20 , a plurality of electrode pairs 30 , and an embedding member 40 .

[0013] The slab waveguide 10 extends in the X1-X2 direction. The slab waveguide 10 has a top surface 11 perpendicular to the Z1-Z2 direction. The cross section of the slab waveguide 10 perpendicular to the X1-X2 direction is rectangular. The dimension (height) of this cross section in the Z1-Z2 direction is, for example, about 100 nm. The refractive index of the slab waveguide 10 is lower than that of diamond. For example, the slab waveguide 10 is made of sapphire, and the top surface 11 is the c-plane of sapphire. The slab waveguide 10 is an example of a waveguide. The X1-X2 direction is an example of a first direction. The top surface 11 is an example of a first surface.

[0014] The nanopillars 20 are made of diamond. The nanopillars 20 are provided on the top surface 11 and are connected to the top surface 11. Multiple nanopillars 20 are aligned in the X1-X2 direction. The nanopillars 20 extend in a second direction tilted from the X1-X2 direction. For example, the second direction is a direction between the X1-X2 direction and the Z1-Z2 direction, and the nanopillars 20 tilt more toward the X2 direction as they move upward (toward the Z1 side). The second direction is parallel to the

[111] direction of the diamond. When viewed from a direction perpendicular to the top surface 11, the second direction overlaps with the X1-X2 direction. The angle θ1 between the top surface 11 of the slab waveguide 10 and the second direction is 28.5°. The nanopillars 20 have a top surface 22 parallel to the top surface 11 of the slab waveguide 10. For example, the dimension of the top surface 22 in the X1-X2 direction is about 100 nm, and the dimension in the Y1-Y2 direction is about 200 nm. The distance between the top surface 11 and the top surface 22 is, for example, about 250 nm to 1000 nm. The top surface 22 is a (110) plane of diamond. The cross section of the nanopillar 20 perpendicular to the second direction has a rectangular shape. This cross section has long sides parallel to the Y1-Y2 direction.

[0015] Each of the multiple nanopillars 20 includes a color center 21. The color center 21 is located near the top surface 22. For example, the distance of the color center 21 from the top surface 22 is 100 nm or less. The color center 21 is, for example, a nitrogen-vacancy center (NV center) composed of a nitrogen atom and a vacancy. In other words, the color center 21 is a complex defect of a nitrogen atom and a vacancy. The direction in which the nitrogen atoms and vacancies are aligned (hereinafter sometimes referred to as the "defect axis direction") is parallel to the

[111] direction of the diamond. The nanopillar 20 including the color center 21 can function as a quantum bit.

[0016] The embedding member 40 is provided on the upper surface 11 of the slab waveguide 10 and fills the gaps between the nanopillars 20. For example, the upper surface of the embedding member 40 is flush with the upper surface 22 of the nanopillars 20. The refractive index of the embedding member 40 is lower than that of diamond. For example, the embedding member 40 is made of silicon oxide (SiO ２ The side surfaces of the nanopillars 20 are in direct contact with the embedding member 40. The nanopillars 20 are surrounded by the embedding member 40.

[0017] An electrode pair 30 is provided for each nanopillar 20. The electrode pair 30 includes electrodes 31 and 32. For example, the electrodes 31 and 32 are provided on an embedding member 40. In a plan view, the color center 21 is located between the electrodes 31 and 32. As viewed from the color center 21, the electrode 31 is on the X1 side, and the electrode 32 is on the X2 side. The material of the electrodes 31 and 32 is not particularly limited, but is preferably a material that has little light absorption in the visible light region, which is the signal wavelength. The material of the electrodes 31 and 32 is, for example, gold (Au), silver (Ag), or copper (Cu).

[0018] Next, a method for manufacturing the quantum device 1 according to the first embodiment will be described. Figures 4 to 11 are cross-sectional views showing the method for manufacturing the quantum device 1 according to the first embodiment. Figures 12 to 15 are plan views showing the method for manufacturing the quantum device 1 according to the first embodiment.

[0019] First, as shown in FIG. 4, a sapphire substrate 15 and a diamond substrate 25 are prepared, and the upper surface of the sapphire substrate 15 is bonded to the lower surface of the diamond substrate 25. The sizes of the sapphire substrate 15 and the diamond substrate 25 are set to, for example, a size that allows multiple quantum devices 1 to be formed in the Y1-Y2 direction. For example, the upper surface of the sapphire substrate 15 is the c-plane, and the upper surface of the diamond substrate 25 is the (110) plane. For example, a high-quality synthetic diamond substrate is used as the diamond substrate 25. For bonding, room-temperature bonding without using a glue, such as surface-activated room-temperature bonding, is desirable. In surface-activated room-temperature bonding, the upper surface of the sapphire substrate 15 and the lower surface of the diamond substrate 25 are activated in a vacuum using argon ions or the like, i.e., dangling bonds are exposed, and the upper surface of the sapphire substrate 15 and the lower surface of the diamond substrate 25 are then bonded together. Bonding may also be performed using a glue that does not have an absorption band in the visible light region. The sapphire substrate 15 is an example of a first substrate, and the diamond substrate 25 is an example of a second substrate.

[0020] 5, the diamond substrate 25 is polished so that the thickness of the diamond substrate 25 matches the distance between the top surface 22 of the nanopillar 20 and the top surface 11 of the slab waveguide 10. The polishing may be performed by, for example, mechanical polishing, chemical mechanical polishing, dry etching, or the like.

[0021] 6 and 12, a mask 60 is formed on the top surface of the diamond substrate 25 in a portion that will become the top surface 22 of the nanopillars 20. The mask 60 is, for example, a silicon nitride (SiN) film. The mask 60 can be formed by, for example, photolithography. FIG. 6 corresponds to a cross-sectional view taken along line VI-VI in FIG. 12.

[0022] 7 and 13, oxygen (O ２ A plurality of nanopillars 20 are formed from the diamond substrate 25 by reactive ion etching (RIE) using ions 61. In this RIE, for example, O ２ The top surface of the diamond substrate 25 is tilted by 28.5° with respect to the incident direction of the ions 61. The nanopillars 20 are formed to extend parallel to the

[111] direction of the diamond. High resistance is achieved by using a SiN film as the mask 60. Figure 7 corresponds to a cross-sectional view taken along line VII-VII in Figure 13.

[0023] 8, the mask 60 is removed to form the filling member 40. The filling member 40 can be formed by, for example, chemical vapor deposition (CVD).

[0024] 9, a color center 21 is formed in each nanopillar 20. To form the NV center, nitrogen ions are implanted. During the ion implantation, the acceleration voltage is adjusted so that the color center 21 can be formed near the top surface 22 of the nanopillar 20. For example, the dose is 10 １０ / cm ２In this case, several color centers 21 are formed for each nanopillar 20. After the ion implantation, an annealing treatment is performed at 1000°C or higher in a vacuum or in an inert gas atmosphere. For example, it is desirable to set the treatment time so that the luminescence characteristics of the color centers 21 (luminescence intensity per color center 21) are optimized.

[0025] 10, the sapphire substrate 15 is thinned to form the slab waveguide 10 from the sapphire substrate 15. The thickness of the slab waveguide 10 is set to, for example, about 100 nm.

[0026] 11 and 14, an electrode pair 30 including electrodes 31 and 32 is formed for each nanopillar 20. At this time, wiring (not shown) connected to the electrode pair 30 is also formed. The electrode pair 30 and wiring are formed on the embedding member 40. FIG. 11 corresponds to a cross-sectional view taken along line XI-XI in FIG.

[0027] 15, the structure shown in Figures 11 and 14 is divided in the Y1-Y2 direction to obtain a plurality of quantum devices 1. The division can be performed by, for example, laser ablation or a dry process.

[0028] In this manner, the quantum device 1 according to the first embodiment can be manufactured.

[0029] Note that color center 21 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.

[0030] Here, an example of how to use the quantum device 1 according to the first embodiment will be described. Fig. 16 is a top view showing an example of how to use the quantum device 1 according to the first embodiment. Fig. 17 is a cross-sectional view showing an example of how to use the quantum device 1 according to the first embodiment.

[0031] In this example, as shown in FIG. 16 , a DC power supply 35 is individually connected to each electrode pair 30. For example, the negative terminal of the DC power supply 35 is connected to electrode 31, and the positive terminal of the DC power supply 35 is connected to electrode 32. Therefore, an electric field is applied from the electrode pair 30 to the color center 21. This electric field includes a component perpendicular to the defect axis of the color center 21 (hereinafter, sometimes referred to as the "perpendicular component"). Furthermore, as shown in FIG. 17 , the color center 21 is irradiated with laser light 26 in the visible light range. The wavelength of the laser light 26 is, for example, 520 nm to 720 nm.

[0032] The color center 21 emits light when irradiated with laser light 26. Because the nanopillar 20 is surrounded by an embedding material 40 with a refractive index lower than that of diamond, the light generated in the color center 21 is confined within the nanopillar 20. This light then propagates within the nanopillar 20 as signal light 27 along the second direction in which the nanopillar 20 extends (a direction parallel to the

[111] direction of the diamond). At this time, the signal light 27 propagates within the nanopillar 20 in a single mode, that is, the TE mode only, which has an electric field amplitude component only in the direction parallel to the long side of the cross section of the nanopillar 20 perpendicular to the second direction (the Y1-Y2 direction). In other words, the signal light 27 propagates within the nanopillar 20 in a single mode in the second direction.

[0033] Furthermore, in this embodiment, the angle of total reflection at the interface 50 between the diamond nanopillar 20 and the slab waveguide 10 made of sapphire is 46.8°, while the angle θ1 between the propagation direction of the signal light 27 within the nanopillar 20 and the interface 50 is 28.5°. In other words, the angle θ1 is smaller than the angle of total reflection. Therefore, the signal light 27 that has propagated to the interface 50 is guided from the nanopillar 20 to the slab waveguide 10 with high efficiency. Furthermore, the signal light 27 guided to the slab waveguide 10 propagates within the slab waveguide 10 while maintaining the single mode of the TE mode.

[0034] Furthermore, the electrode pairs 30 and wiring are formed on the embedding member 40. Therefore, compared to when the metal electrode pairs 30 or wiring are formed on the nanopillars 20, the signal light 27 can be more easily confined within the nanopillars 20, and optical loss caused by the metal can be reduced.

[0035] Here, control of the wavelength of the signal light 27 will be described. In this embodiment, an electric field having a vertical component can be applied to the color center 21. When such an electric field is applied, the optical transition wavelength in the color center 21 changes due to the Stark effect. The amount of change ΔE in the optical transition frequency is expressed by the following equation (1), taking into account up to the second-order term of F, where F is the strength of the vertical component of the electric field.

[0036]

[0037] In Equation 1, Δμ is the amount of change in dipole moment between the ground and excited levels, Δα is the amount of change in polarizability tensor between the ground and excited levels, and ε is the relative dielectric constant of diamond.

[0038] When the color center 21 is an NV center, the relationship between the intensity F of the perpendicular component and the change ΔE in the optical transition frequency is as shown in Fig. 18. Since the NV center has low symmetry in the defect axis direction, Δα is substantially 0 Å. ３ and ΔE is expressed as a linear expression of F. The value of Δμ (4.329×10 －３０ When the vertical component F was used, it was found that, as shown in FIG. 18, if the strength F of the vertical component was changed by about 1.0 MV / m, ΔE could be changed by about 5 GHz.

[0039] When the color center 21 is a SnV center, there is a relationship shown in FIG. 19 between the intensity F of the perpendicular component and the change ΔE in the optical transition frequency. Since the SnV center has high symmetry in the defect axis direction, ΔE is insensitive to the first-order term of F, but is significantly affected by the second-order term of F. The value of Δμ (1.332×10) obtained from the description in Non-Patent Document 4 is －２４ C·m) and Δα value (0.23 Å ３ ) was used, and the result was that, as shown in FIG. 19, if the strength F of the vertical component was changed by about 1.0 MV / m, ΔE could be changed by about 5 GHz.

[0040] From these results, it can be said that the optical transition frequency of the color center 21 can be adjusted in the range of about 5 GHz by applying an electric field using the electrode pair 30. In other words, it can be said that the emission wavelength of the color center 21 can be adjusted.

[0041] Furthermore, in this embodiment, multiple nanopillars 20 and slab waveguides 10 overlap in the Z1-Z2 direction, which allows for improved integration compared to a configuration in which quantum bits and waveguides are arranged within a single plane.

[0042] For example, assume that the dimension of the top surface 22 in the X1-X2 direction is 100 nm, the dimensions of the electrodes 31 and 32 are 30 nm, the distance between adjacent top surfaces 22 is 200 nm, and the dimension of the top surface 22 in the Y1-Y2 direction is 200 nm. In this case, within the plane including each top surface 22, the dimension of the region for securing two quantum bits in the X1-X2 direction is 460 nm, the dimension in the Y1-Y2 direction is 200 nm, and the area is 0.092 μm ２ Therefore, the area occupied by one quantum bit is 0.046 μm ２ In contrast, the area occupied by one quantum bit in the superconducting quantum computer described in Non-Patent Document 5 is 90,000 μm ２ That is, according to this embodiment, the area required per quantum bit can be reduced by about seven orders of magnitude.

[0043] As described above, in this embodiment, since the nanopillars 20 overlap each other in the Z1-Z2 direction, the spacing between the nanopillars 20 in a plane parallel to the top surface 11 can be narrowed, thereby improving the integration density of quantum bits.

[0044] According to this embodiment, it is possible to adjust the emission wavelength of the color center 21 and improve the integration density of the quantum bits at the same time. The improvement in integration density enables the scale of the optical circuit including the color center 21 to be increased.

[0045] The electrodes 31 and 32 included in the electrode pair 30 are preferably made of a material that has low light absorption in the visible light region. FIG. 20 is a diagram showing the relationship between wavelength and transmittance for various metals. FIG. 20 shows the transmittance of 5-nm-thick films of Au, Ag, Cu, and Al calculated using the Drude model. As shown in FIG. 20, Au, Ag, or Cu can achieve higher transmittance than Al.

[0046] The second direction does not need to be parallel to the

[111] direction of the diamond. The angle θ1 is preferably smaller than the angle of total reflection at the interface 50.

[0047] Second Embodiment A second embodiment will now be described. Fig. 21 is a diagram showing a quantum processing device according to the second embodiment. The quantum processing device 2 functions as a quantum computer.

[0048] The quantum processing device 2 according to the second embodiment includes quantum modules 70 and 80, a plurality of control systems 72 and 82, optical switches 73 and 83, and single-photon detectors 74 and 84. The quantum processing device 2 further includes a cooler 90, a control unit 91, an AD converter 92, a beam splitter 93, and a comparator 94. The quantum modules 70 and 80, the control systems 72 and 82, the optical switches 73 and 83, the single-photon detectors 74 and 84, the AD converter 92, the beam splitter 93, and the comparator 94 are housed inside the cooler 90. The temperature inside the cooler 90 is 4 K or less.

[0049] The control unit 91 outputs an analog control signal to an AD converter 92, which converts the analog signal into a digital signal, which is then input to the control systems 72 and 82. The control unit 91 is, for example, a personal computer.

[0050] The quantum device 1 according to the first embodiment is used as the quantum modules 70 and 80. The quantum module 70 includes a plurality of quantum bits 71, and the quantum module 80 includes the same number of quantum bits 81 as the quantum bits 71. The quantum bits 71 and 81 correspond to the nanopillars 20 including the color centers 21 in the quantum device 1. A control system 72 is provided for each quantum bit 71, and a control system 82 is provided for each quantum bit 81. The control systems 72 each control the magnetic field, electric field, and microwaves applied to the corresponding quantum bit 71, and irradiate the corresponding quantum bit 71 with laser light. The control systems 82 each control the magnetic field, electric field, and microwaves applied to the corresponding quantum bit 81, and irradiate the corresponding quantum bit 81 with laser light. The application of a magnetic field is used to create a state of the color centers 21 that performs quantum manipulation. The application of a microwave is used to control the state of the color centers 21. The irradiation of laser light is used to read out the state of the color centers 21 (single photon generation). The application of an electric field is used to control the emission wavelength of the color center 21. The electric field is controlled via an electrode pair 30.

[0051] The signal light (photons) generated in quantum module 70 is input to optical switch 73, which outputs the signal light to single-photon detector 74 or beam splitter 93. Furthermore, the signal light (photons) generated in quantum module 80 is input to optical switch 83, which outputs the signal light to single-photon detector 84 or beam splitter 93. The signal light input to beam splitter 93 is output to single-photon detectors 74 and 84. In this way, the path of the signal light generated in quantum module 70 is switched by optical switch 73 between a path that is guided directly to single-photon detector 74 and a path that is guided to single-photon detector 74 via beam splitter 93. Similarly, the path of the signal light generated in quantum module 80 is switched by optical switch 83 between a path that is guided directly to single-photon detector 84 and a path that is guided to single-photon detector 84 via beam splitter 93.

[0052] For example, when reading out the state of a single quantum bit, the optical switch 73 or 83 guides the signal light directly from the quantum module 70 or 80 to the single-photon detector 74 or 84. For example, when performing entanglement manipulation between color center spins corresponding to a multi-gate operation, the optical switch 73 or 83 guides the signal light from the quantum module 70 or 80 to the single-photon detector 74 or 84 via the beam splitter 93. At this time, nanopillars 20 with equal optical path lengths from the beam splitter 93 are used between the quantum module 70 and the quantum module 80.

[0053] The comparator 94 is used during entanglement manipulation, and compares the detection signals of single photons (whether they are detected by the single-photon detector 74 or 84 and in what order) after being split by the beam splitter 93. The result of analyzing the output from the comparator 94 corresponds to the result of the operation by the quantum operation device 2.

[0054] Note that no spectrometer is used to adjust the emission wavelength between quantum modules 70 and 80, and the emission wavelength is adjusted by an electric field applied using electrode pair 30 while monitoring quantum interference (HOM interference) between two photons. HOM interference is a phenomenon in which, when photons are incident on a beam splitter from two ports, the photon is always detected by only one of the detectors.

[0055] According to the quantum processing device 2 configured in this manner, the quantum device 1 according to the first embodiment is used in the quantum modules 70 and 80, so that the integration density of quantum bits can be improved. Furthermore, a highly reliable and practical quantum processing device 2 can be obtained.

[0056] Although the preferred embodiments have been described above in detail, 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.

[0057] 1: Quantum device 2: Quantum processing unit 10: Slab waveguide 11: Upper surface 15: Sapphire substrate 20: Nanopillar 21: Color center 22: Upper surface 25: Diamond substrate 30: Electrode pair 31, 32: Electrodes 40: Embedded member 50: Interface

Claims

1. a waveguide having a first surface and extending in a first direction parallel to the first surface; A plurality of nanopillars connected to the first surface and aligned in the first direction; a color center formed in each of the plurality of nanopillars; An electrode pair provided for each of the color centers; having Each of the nanopillars extends in a second direction inclined from the first direction and inclined from a normal direction of the first surface; A quantum device, wherein an electric field is applied to the color center from the electrode pair.

2. 2. The quantum device according to claim 1, further comprising a filling member provided on the first surface and filling gaps between the nanopillars.

3. 3. The quantum device according to claim 2, wherein the material of the nanopillar is diamond, and the refractive index of the embedding member is lower than the refractive index of diamond.

4. 4. The quantum device according to claim 2, wherein the electrode pair is provided on the embedding member.

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

6. 3. The quantum device according to claim 1, wherein the first direction and the second direction overlap when the first surface is viewed from the normal direction.

7. 3. The quantum device according to claim 1, wherein an angle between the first surface and the second direction is smaller than an angle of total reflection at an interface between the waveguide and the nanopillar.

8. 3. The quantum device according to claim 1, wherein the electric field includes a component perpendicular to a direction in which the atoms and vacancies constituting the color center are aligned.

9. The nanopillar has a rectangular cross section perpendicular to the second direction, 3. The quantum device according to claim 1, wherein light propagating through the nanopillar propagates in a single mode in the second direction.

10. 10. The quantum device according to claim 9, wherein light propagating through the nanopillar has an electric field amplitude component only in a direction parallel to a long side of the cross section.

11. bonding a second substrate having a higher refractive index than the first substrate to a first surface of the first substrate; processing the second substrate to form a plurality of nanopillars aligned in a first direction parallel to the first surface; forming a color center on each of the plurality of nanopillars; forming an electrode pair for each of the color centers; having Each of the nanopillars extends in a second direction inclined from the first direction and inclined from a normal direction of the first surface; A method for manufacturing a quantum device, comprising applying an electric field to the color center from the electrode pair.