Quantum devices and methods for manufacturing quantum devices

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

[Technical Field]

[0001] This disclosure relates to quantum devices and methods for manufacturing quantum devices. [Background technology]

[0002] In recent years, research and development of quantum computers have been actively pursued. For example, quantum computers that use the electron spin levels of color centers in diamond as qubits are known. In such quantum computers, information about electron spins is converted into information about photons, which are then read optically. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] U.S. Patent Application Publication No. 2011 / 0309265 [Patent Document 2] U.S. Patent Application Publication No. 2012 / 0161663 [Patent Document 3] Special Publication No. 2015-529328 [Patent Document 4] Special Publication No. 2007-526639 [Non-patent literature]

[0004] [Non-Patent Document 1] CT Nguyen et al., Phys. Rev. Lett. 123, 183602, (2019) [Non-Patent Document 2] A. Sipahigil et al., Science 354, 847 (2016) [Non-Patent Document 3] Ph. Tamarat et al., PHYSICAL REVIEW LETTERS 97, 083002 (2006) [Non-Patent Document 4] LD Santis et al., PHYSICAL REVIEW LETTERS 127, 147402 (2021) [Non-Patent Document 5] J. Lisenfeld npj Quantum Information (2019) 5:105 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] A quantum computer contains multiple qubits. For computation, it is desirable that the emission wavelengths of color centers match in order to ensure the indiscriminate nature of photons necessary for entanglement between multiple qubits. However, the emission wavelengths of color centers differ by GHz in frequency due to defects or distortions around the color center. While techniques for adjusting the emission wavelengths of color centers have been proposed, arranging multiple qubits with high integration density remains difficult.

[0006] The object of this disclosure is to provide a quantum device and a method for manufacturing a quantum device that can improve the integration density of qubits. [Means for solving the problem]

[0007] According to one embodiment of the present disclosure, 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 on each of the plurality of nanopillars, and an electrode pair provided for each of the color centers, wherein each of the plurality of nanopillars extends in a second direction inclined from the first direction and inclined from the normal direction of the first surface, The first direction and the third direction obtained by projecting the second direction onto the first plane are parallel. A quantum device is provided in which an electric field is applied from the electrode pair to the color center. [Effects of the Invention]

[0008] According to this disclosure, the integration density of qubits can be improved.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a perspective view showing a quantum device according to the first embodiment. [Figure 2] FIG. 2 is a plan view showing a quantum device according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing a quantum device according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view (Part 1) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view (Part 2) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view (Part 3) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view (Part 4) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view (Part 5) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 9] FIG. 9 is a cross-sectional view (Part 6) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 10] FIG. 10 is a cross-sectional view (Part 7) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 11] FIG. 11 is a cross-sectional view (Part 8) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 12] FIG. 12 is a plan view (Part 1) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 13] FIG. 13 is a plan view (Part 2) showing a method for manufacturing a quantum device according to the first embodiment [Figure 14] FIG. 14 is a plan view (Part 3) showing a method for manufacturing a quantum device according to the first embodiment [Figure 15]Figure 15 is a plan view (part 4) showing a method for manufacturing a quantum device according to the first embodiment. [Figure 16] Figure 16 is a top view showing an example of how to use the quantum device according to the first embodiment. [Figure 17] Figure 17 is a cross-sectional view showing an example of how to use the quantum device according to the first embodiment. [Figure 18] Figure 18 is a diagram (part 1) showing the relationship between the electric field strength F and the change in optical transition frequency ΔE. [Figure 19] Figure 19 is a diagram (part 2) showing the relationship between the electric field strength F and the change in optical transition frequency ΔE. [Figure 20] Figure 20 shows the relationship between wavelength and transmittance for various metals. [Figure 21] Figure 21 shows a quantum computing device according to the second embodiment. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described in detail below with reference to the attached drawings. In this specification and drawings, components having substantially the same functional configuration will be denoted by the same reference numerals to avoid redundant explanations. In this disclosure, the X1-X2 direction, Y1-Y2 direction, and Z1-Z2 direction are mutually orthogonal directions. A plane including the X1-X2 direction and the Y1-Y2 direction is described as the XY plane, a plane including the Y1-Y2 direction and the Z1-Z2 direction is described as the YZ plane, and a plane including the Z1-Z2 direction and the X1-X2 direction is described as the ZX plane. For convenience, the Z1-Z2 direction is considered the up and down direction, with the Z1 side being the upper side and the Z2 side being the lower side. Furthermore, a plan view means viewing the object from the Z1 side, and a planar shape means the shape of the object as viewed from the Z1 side.

[0011] (First Embodiment) A first embodiment will now be described. Figure 1 is a perspective view showing a quantum device according to the first embodiment. Figure 2 is a plan view showing a quantum device according to the first embodiment. Figure 3 is a cross-sectional view showing a quantum device according to the first embodiment. Figure 3 corresponds to a cross-sectional view along the line III-III in Figure 2.

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

[0013] The slab waveguide 10 extends in the X1-X2 direction. The slab waveguide 10 has an upper surface 11 perpendicular to the Z1-Z2 direction. The cross-sectional shape 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 upper 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 upper surface 11 is an example of a first surface.

[0014] The nanopillars 20 are made of diamond. The nanopillars 20 are mounted on the upper surface 11 and connected to the upper surface 11. Multiple nanopillars 20 are arranged in the X1-X2 direction. The nanopillars 20 extend in a second direction that is inclined from the X1-X2 direction. For example, the second direction is between the X1-X2 direction and the Z1-Z2 direction, and the nanopillars 20 are inclined so that they move towards the X2 side as they move upward (towards the Z1 side). The second direction is parallel to the

[0111] direction of the diamond. When viewed from a direction perpendicular to the upper surface 11, the second direction coincides with the X1-X2 direction. The angle θ1 between the upper surface 11 of the slab waveguide 10 and the second direction is 28.5°. The nanopillars 20 have an upper surface 22 that is parallel to the upper surface 11 of the slab waveguide 10. For example, the dimension of the upper surface 22 in the X1-X2 direction is approximately 100 nm, and the dimension in the Y1-Y2 direction is approximately 200 nm. The distance between the upper surface 11 and the upper surface 22 is, for example, approximately 250 nm to 1000 nm. The upper surface 22 is a (110) plane of diamond. The shape of the cross-section of the nanopillar 20 perpendicular to the second direction is rectangular. This cross-section has a long side parallel to the Y1-Y2 direction.

[0015] Each of the multiple nanopillars 20 contains 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 a nitrogen-vacancy center (NV center) composed of, for example, a nitrogen atom and a vacancy. That is, the color center 21 is a composite defect of a nitrogen atom and a vacancy. The direction in which the nitrogen atom and vacancy are aligned (hereinafter sometimes referred to as the "defect axis direction") is parallel to the

[0111] direction of the diamond. A nanopillar 20 containing a color center 21 can function as a qubit.

[0016] The embedded member 40 is provided on the upper surface 11 of the slab waveguide 10 and fills the gaps between the multiple nanopillars 20. For example, the upper surface of the embedded member 40 is flush with the upper surface 22 of the nanopillars 20. The refractive index of the embedded member 40 is lower than that of diamond. For example, the embedded member 40 is made of silicon oxide (SiO2). The sides of the nanopillars 20 are in direct contact with the embedded member 40. The nanopillars 20 are surrounded by the embedded member 40.

[0017] An electrode pair 30 is provided for each nanopillar 20. The electrode pair 30 includes electrodes 31 and 32. For example, electrodes 31 and 32 are provided on an embedded member 40. In a plan view, a color center 21 is located between electrodes 31 and 32. With respect to the color center 21, electrode 31 is on the X1 side and electrode 32 is on the X2 side. The material of electrodes 31 and 32 is not particularly limited, but it is preferable that it be a material that has low light absorption in the visible light region, which is the signal wavelength. Examples of materials for electrodes 31 and 32 are 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 Figure 4, a sapphire substrate 15 and a diamond substrate 25 are prepared, and the upper surface of the sapphire substrate 15 and the lower surface of the diamond substrate 25 are joined together. The sizes of the sapphire substrate 15 and the diamond substrate 25 are such that multiple quantum devices 1 can 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 the diamond substrate 25, for example, a high-quality synthetic diamond substrate is used. For joining, a room-temperature bonding method that does not use adhesives, such as surface-activated room-temperature bonding, is preferable. 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, that is, the dangling bond is exposed, and the upper surface of the sapphire substrate 15 and the lower surface of the diamond substrate 25 are bonded together. Bonding using an adhesive that does not have an absorption band in the visible light region may also be performed. The sapphire substrate 15 is an example of a first substrate, and the diamond substrate 25 is an example of a second substrate.

[0020] Next, as shown in Figure 5, the diamond substrate 25 is polished to match the thickness of the diamond substrate 25 to the distance between the upper surface 22 of the nanopillar 20 and the upper surface 11 of the slab waveguide 10. Polishing can be done by mechanical polishing, chemical mechanical polishing, or dry etching, for example.

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

[0022] Next, as shown in Figures 7 and 13, multiple nanopillars 20 are formed from the diamond substrate 25 by reactive ion etching (RIE) using oxygen (O2) ions 61 incident from a direction parallel to the

[0111] direction of the diamond substrate 25. In this RIE, for example, the upper surface of the diamond substrate 25 is tilted at 28.5° with respect to the incident direction of the O2 ions 61. The nanopillars 20 are formed to extend parallel to the

[0111] direction of the diamond. High resistance is obtained by using a SiN film as the mask 60. Figure 7 corresponds to a cross-sectional view along the line VII-VII in Figure 13.

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

[0024] Subsequently, as shown in Figure 9, a color center 21 is formed in each nanopillar 20. When forming NV centers, nitrogen ion implantation is performed. During ion implantation, the acceleration voltage is adjusted so that the color center 21 is formed near the upper surface 22 of the nanopillar 20. Also, for example, the dose amount is 10 10 / cm 2 The following applies. In this case, several color centers 21 are formed for each nanopillar 20. After ion implantation, an annealing treatment is performed at 1000°C or higher in a vacuum or inert gas atmosphere. For example, the treatment time should be set so that the luminescence characteristics of the color centers 21 (luminescence intensity per color center 21) are optimized.

[0025] Next, as shown in Figure 10, the sapphire substrate 15 is thinned to form a slab waveguide 10 from the sapphire substrate 15. The thickness of the slab waveguide 10 is, for example, about 100 nm.

[0026] Next, as shown in Figures 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 embedded member 40. Figure 11 corresponds to a cross-sectional view along the line XI-XI in Figure 14.

[0027] Subsequently, as shown in Figure 15, multiple quantum devices 1 are obtained by splitting the structures shown in Figures 11 and 14 in the Y1-Y2 direction. Splitting can be performed, for example, by laser ablation or a dry process.

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

[0029] Furthermore, the 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, we will describe an example of how to use the quantum device 1 according to the first embodiment. Figure 16 is a top view showing an example of how to use the quantum device 1 according to the first embodiment. Figure 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 Figure 16, a DC power supply 35 is connected to each electrode pair 30 individually. 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. Thus, 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"). Also, as shown in Figure 17, the color center 21 is irradiated with laser light 26 in the visible light region. 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. Since the nanopillar 20 is surrounded by an embedded member 40 with a lower refractive index than 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 (the direction parallel to the

[0111] direction of the diamond). At this time, the signal light 27 propagates within the nanopillar 20 in a single mode consisting only of the TE mode, which has an electric field amplitude component only in the direction parallel to the long side of the cross-section perpendicular to the second direction of the nanopillar 20 (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 total reflection angle at the interface 50 between the diamond nanopillar 20 and the sapphire slab waveguide 10 is 46.8°, while the angle θ1 between the direction of propagation of the signal light 27 within the nanopillar 20 and the interface 50 is 28.5°. That is, angle θ1 is smaller than the total reflection angle. 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. Moreover, the signal light 27 guided to the slab waveguide 10 propagates within the slab waveguide 10 while maintaining a single TE mode.

[0034] Furthermore, the electrode pair 30 and wiring are formed on the embedded member 40. Therefore, compared to the case where the metal electrode pair 30 or wiring is formed on the nanopillar 20, the signal light 27 is more easily confined within the nanopillar 20, and optical loss due to metal can be reduced.

[0035] Here, we will explain how to control the wavelength of the signal light 27. 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 at the color center 21 changes due to the Stark effect. The amount of change ΔE in the optical transition frequency is given by the following equation (1), where F is the strength of the vertical component of the electric field, and considering up to the second-order term of F.

[0036]

number

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

[0038] When color center 21 is an NV center, the relationship between the intensity F of the vertical component and the change in optical transition frequency ΔE is as shown in Figure 18. In NV centers, the symmetry in the direction of the defect axis is low, so Δα is substantially 0 Å. 3 Therefore, ΔE is expressed as a linear function of F. The value of Δμ obtained from the description in Non-Patent Document 3 is (4.329 × 10⁻¹⁴). -30 Using C·m, ​​as shown in Figure 18, we obtained the result that changing the strength F of the vertical component by about 1.0 MV / m would change ΔE by about 5 GHz.

[0039] When color center 21 is an SnV center, there is a relationship between the intensity F of the vertical component and the change in optical transition frequency ΔE, as shown in Figure 19. In SnV centers, the symmetry in the direction of the defect axis is high, so ΔE is insensitive to the first-order term of F, and the influence of the second-order term of F is large. The value of Δμ obtained from the description in Non-Patent Literature 4 is (1.332 × 10⁻¹⁰ -24 The values ​​of C·m and Δα (0.23 Å) 3 Using this method, as shown in Figure 19, we obtained the result that changing the strength F of the vertical component by about 1.0 MV / m would change ΔE by about 5 GHz.

[0040] These results suggest that the optical transition frequency of the color center 21 can be adjusted within a range of approximately 5 GHz by applying an electric field using the electrode pair 30. In other words, the emission wavelength at the color center 21 can be adjusted.

[0041] In addition, in the present embodiment, since a plurality of nanopillars 20 and the slab waveguide 10 overlap in the Z1-Z2 direction, the integration density can be improved as compared with a configuration in which qubits and the waveguide are arranged in one plane.

[0042] For example, in the X1-X2 direction, assume that the dimension of the upper surface 22 is 100 nm, the dimensions of the electrodes 31 and 32 are 30 nm, the distance between adjacent upper surfaces 22 is 200 nm, and the dimension of the upper surface 22 in the Y1-Y2 direction is 200 nm. In this case, in the plane including each upper surface 22, the dimension of the region for securing two qubits 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 exclusive area per qubit is 0.046 μm. 2 On the other hand, the exclusive area per qubit of the superconducting quantum computer described in Non-Patent Document 5 is 90,000 μm. 2 That is, according to the present embodiment, the exclusive area per qubit can be formed to be about seven orders of magnitude smaller.

[0043] Thus, in the present embodiment, since there is an overlap between the nanopillars 20 in the Z1-Z2 direction, the interval between the nanopillars 20 in the plane parallel to the upper surface 11 can be narrowed, and the integration density of the qubits can be improved.

[0044] According to the present embodiment, it is possible to achieve both adjustment of the emission wavelength of the color center 21 and improvement of the integration density of the qubits. With the improvement of the integration density, it becomes possible to increase the scale of the optical circuit including the color center 21.

[0045] The electrodes 31 and 32 included in the electrode pair 30 are preferably made of a material with little light absorption in the visible light region. FIG. 20 is a diagram showing the relationship between wavelength and transmittance in various metals. FIG. 20 shows the transmittance of films of Au, Ag, Cu, and Al with a thickness of 5 nm calculated using the Drude model. As shown in FIG. 20, according to Au, Ag, or Cu, a higher transmittance can be obtained than Al.

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

[0111] direction of the diamond. It is preferable that the angle θ1 is smaller than the total reflection angle at interface 50.

[0047] (Second Embodiment) A second embodiment will now be described. Figure 21 shows a quantum computing device according to the second embodiment. The quantum computing device 2 functions as a quantum computer.

[0048] The quantum computing 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 computing 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 4K or less.

[0049] The control unit 91 outputs an analog signal for control to the AD converter 92, which converts the analog signal into a digital signal, and the digital signal is 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. Quantum module 70 includes a plurality of qubits 71, and quantum module 80 includes the same number of qubits 81 as qubits 71. The qubits 71 and 81 correspond to the nanopillar 20 containing the color center 21 in the quantum device 1. A control system 72 is provided for each qubit 71, and a control system 82 is provided for each qubit 81. Each control system 72 controls the magnetic field, electric field, and microwave applied to the corresponding qubit 71, and irradiates the corresponding qubit 71 with laser light. Each control system 82 controls the magnetic field, electric field, and microwave applied to the corresponding qubit 81, and irradiates the corresponding qubit 81 with laser light. The application of a magnetic field is used to form the state of the color center 21 that performs quantum operations. The application of microwaves is used to control the state of the color center 21. The irradiation of laser light is used to read out the state of the color center 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 the 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. Similarly, 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. Thus, the path of the signal light generated in quantum module 70 is switched by optical switch 73 between a path that directly guides the signal light to single-photon detector 74 and a path that guides the signal light to single-photon detector 74 via beam splitter 93. Likewise, the path of the signal light generated in quantum module 80 is switched by optical switch 83 between a path that directly guides the signal light to single-photon detector 84 and a path that guides the signal light to single-photon detector 84 via beam splitter 93.

[0052] For example, when reading out the state of a single qubit, the signal light is directly guided from the quantum module 70 or 80 to the single-photon detector 74 or 84 by the optical switch 73 or 83. For example, when performing an entanglement operation between the spins of a color center corresponding to a multi-gate operation, the signal light is guided from the quantum module 70 or 80 to the single-photon detector 74 or 84 via the beam splitter 93 by the optical switch 73 or 83. In this case, 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] Comparator 94 is used during the entanglement operation to compare the detection signals of single photons after they have been split by beam splitter 93 (determining which single photon detector 74 or 84 detects them and in what order). The results of the analysis of the output from comparator 94 correspond to the results of the calculations performed by quantum computing device 2.

[0054] Furthermore, a spectrometer is not used to adjust the emission wavelength between quantum modules 70 and 80. Instead, the emission wavelength is adjusted by an electric field applied using electrode pair 30 while monitoring quantum interference between two photons (HOM interference). HOM interference is a phenomenon in which, when photons are incident on the beam splitter from two separate ports, the photons are always detected by only one of the detectors.

[0055] With the quantum computing device 2 configured in this way, the quantum device 1 according to the first embodiment is used in the quantum modules 70 and 80, which improves the integration density of qubits. Furthermore, a highly reliable and practical quantum computing device 2 can be obtained.

[0056] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims. [Explanation of Symbols]

[0057] 1: Quantum devices 2: Quantum computing device 10: Slab waveguide 11:Top surface 15: Sapphire substrate 20: Nanopillar 21: Color Center 22:Top surface 25: Diamond substrate 30: Electrode pair 31, 32: Electrode 40: Embedded component 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, Each of the aforementioned color centers is provided with a pair of electrodes, It has, Each of the plurality of nanopillars extends in a second direction that is inclined from the first direction and inclined from the direction normal to the first surface, The first direction and the third direction obtained by projecting the second direction onto the first plane are parallel. A quantum device characterized in that an electric field is applied from the electrode pair to the color center.

2. The quantum device according to claim 1, characterized in that it has an embedded member provided on the first surface and filling the gaps between the plurality of nanopillars.

3. The quantum device according to claim 2, characterized in that the material of the nanopillar is diamond, and the refractive index of the embedded member is lower than the refractive index of diamond.

4. The quantum device according to claim 2 or 3, characterized in that the electrode pair is provided on the embedded member.

5. The quantum device according to claim 1 or 2, characterized in that the material of the nanopillar is diamond, and the refractive index of the waveguide is lower than the refractive index of diamond.

6. The quantum device according to claim 1 or 2, characterized in that the angle between the first surface and the second direction is smaller than the total reflection angle at the interface between the waveguide and the nanopillar.

7. The quantum device according to claim 1 or 2, characterized in that the electric field includes a component perpendicular to the direction in which the atoms and vacancies constituting the color center are aligned.

8. The cross-sectional shape of the nanopillar perpendicular to the second direction is rectangular. The quantum device according to claim 1 or 2, characterized in that the light propagating through the nanopillar propagates in a single mode in the second direction.

9. The quantum device according to claim 8, characterized in that the light propagating through the nanopillar has an electric field amplitude component only in a direction parallel to the long side of the cross-section.

10. A step of bonding a second substrate having a higher refractive index than the first substrate to the first surface of the first substrate, A step of processing the second substrate to form a plurality of nanopillars arranged in a first direction parallel to the first surface, A step of forming a color center in each of the plurality of nanopillars, The process of forming an electrode pair for each of the aforementioned color centers, It has, Each of the plurality of nanopillars extends in a second direction that is inclined from the first direction and inclined from the direction normal to the first surface, The first direction and the third direction obtained by projecting the second direction onto the first plane are parallel. A method for manufacturing a quantum device, characterized in that an electric field is applied from the electrode pair to the color center.

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