Ion trap tip

Abstract

This enables the creation of an ion trap chip with high photon collection efficiency. [Solution] The ion trap chip (1) comprises an electrode substrate (10) that holds ions (I) which become qubits in space, a first optical circuit board (300) having a first optical waveguide (110), and a light-receiving unit (120) that receives photons emitted from the ions and introduces the photons into the first optical waveguide, with the light-receiving unit facing the electrode substrate with the ions in between.

Description

Technical Field

[0001] The present invention relates to an ion trap chip.

Background Art

[0002] As described in Non-Patent Document 1, an ion trap chip that captures ions using electrodes on an ion trap electrode substrate, irradiates the ions with a laser pulse to generate fluorescence and emit photons, collects the photons by a grating of a light receiving part, and introduces the photons into an optical waveguide is known as a conventional technique.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology as described above, the light receiving part is embedded below the ion trap electrode substrate (for example, FIG. 2), and it is necessary to arrange the light receiving part avoiding the positions where the electrodes are located. Therefore, the collection efficiency of photons in the light receiving part becomes low.

[0005] One aspect of the present invention aims to realize an ion trap chip with high photon collection efficiency.

Means for Solving the Problems

[0006] To solve the above problems, an ion trap chip according to embodiment 1 of the present invention comprises an ion trap electrode substrate that holds ions that become qubits in space, an optical waveguide, and a first optical circuit board having a light receiving unit that receives photons emitted from the ions and introduces the photons into the optical waveguide, wherein the light receiving unit is configured to face the ion trap electrode substrate with the ions in between.

[0007] According to the above configuration, no interference occurs between the light-receiving unit and the ion trap electrode substrate, and the light-receiving unit can be positioned to increase the photon collection efficiency in the light-receiving unit. Furthermore, according to the above configuration, the first optical circuit board having the light-receiving unit and the ion trap electrode substrate are separate, and each substrate can be manufactured separately and then stacked, making it easy to integrate multiple components during the manufacturing of the ion trap chip.

[0008] An ion trap chip according to embodiment 2 of the present invention may have a magnetic field forming unit that forms a magnetic field at the position where the ions are held, and a light receiving unit that has a first grating that is arranged obliquely with respect to the direction of the magnetic field in a plan view.

[0009] With the above configuration, two mutually orthogonal polarizations can be collected for each first grating, and the light-receiving section can be positioned to increase the photon collection efficiency at the light-receiving section.

[0010] In the ion trap chip according to embodiment 3 of the present invention, the first optical circuit board may be configured to include a first optical transmission layer on which the light receiving portion is formed, and a second optical transmission layer on which a light emitting portion for irradiating the ions with light is formed.

[0011] With the above configuration, the light emission unit can be integrated onto the chip, making it easy to integrate multiple components during the manufacturing of the ion trap chip. Furthermore, since the first optical transmission layer on which the light receiving unit is formed and the second optical transmission layer on which the light emission unit is formed are separate, each layer can be manufactured separately and then superimposed, making it easy to integrate multiple components during the manufacturing of the ion trap chip.

[0012] The ion trap chip according to embodiment 4 of the present invention may be configured in which, in embodiment 1 or 2 above, a second optical circuit board is provided on the side of the first optical circuit board relative to the ions, and a light emission section for irradiating the ions with light is formed thereon.

[0013] With the above configuration, the light emission unit can be integrated onto a chip, making it easy to integrate multiple components during the manufacturing of the ion trap chip. Furthermore, since the first optical circuit board on which the light receiving unit is formed and the second optical circuit board on which the light emission unit is formed are separate, each board can be manufactured separately and then stacked, making it easy to integrate multiple components during the manufacturing of the ion trap chip.

[0014] In the ion trap chip according to embodiment 5 of the present invention, in embodiment 3 or 4 described above, the light receiving portion and the light emitting portion may be arranged so as not to overlap each other in a plan view.

[0015] According to the above configuration, the light emission unit can be integrated onto a chip, making it easy to integrate multiple components during the manufacturing of the ion trap chip. Furthermore, since the first optical transmission layer or first optical circuit board on which the light receiving unit is formed and the second optical transmission layer or second optical circuit board on which the light emission unit is formed are separate, each layer or each substrate can be manufactured separately and then stacked, making it easy to integrate multiple components during the manufacturing of the ion trap chip.

[0016] In the ion trap chip according to embodiment 6 of the present invention, in embodiment 3 or 4 above, the light receiving portion may have a first grating for receiving the photons, and the light emitting portion may have a second grating that overlaps with the region in the light receiving portion where the first grating is not formed.

[0017] According to the above configuration, the light emission unit can be integrated onto a chip, making it easy to integrate multiple components during the manufacturing of the ion trap chip. Furthermore, since the first optical transmission layer or first optical circuit board on which the light receiving unit is formed and the second optical transmission layer or second optical circuit board on which the light emission unit is formed are separate, each layer or each substrate can be manufactured separately and then stacked, making it easy to integrate multiple components during the manufacturing of the ion trap chip.

[0018] In the ion trap chip according to embodiment 7 of the present invention, in embodiment 6 described above, the light receiving portion has a shaping region formed between the first grating and the optical waveguide for transmitting the photons, and the second grating may be configured to overlap the shaping region of the light receiving portion in a plan view.

[0019] According to the above configuration, the light emission unit can be integrated onto a chip, making it easy to integrate multiple components during the manufacturing of the ion trap chip. Furthermore, since the first optical transmission layer or first optical circuit board on which the light receiving unit is formed and the second optical transmission layer or second optical circuit board on which the light emission unit is formed are separate, each layer or each substrate can be manufactured separately and then stacked, making it easy to integrate multiple components during the manufacturing of the ion trap chip.

[0020] An ion trap chip according to embodiment 8 of the present invention may be configured such that, in any one embodiment of embodiments 1 to 7 above, the light receiving portion has a first grating for receiving the photons, and the first optical circuit board includes a first optical transmission layer on which the light receiving portion is formed, and a conductive layer located on the ion side of the first optical transmission layer, wherein the conductive layer has a conductive film formed in a region other than the first grating.

[0021] According to the above configuration, the conductive film can protect the optical circuit from electric field noise.

Effects of the Invention

[0022] According to one aspect of the present invention, an ion trap chip with high photon collection efficiency can be realized.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 15 is a cross-sectional view showing a schematic configuration of an ion trap chip according to Embodiment 1. [Figure 2] FIG. 18 is a plan view showing the configuration of the electrode substrate of the ion trap chip according to Embodiment 1. [Figure 3] FIG. 21 is a plan view showing the configuration of the first optical circuit substrate according to Embodiment 1. [Figure 4] FIG. 24 is a cross-sectional view showing a schematic configuration of an ion trap chip according to Embodiment 1. [Figure 5] FIG. 27 is a diagram showing a schematic configuration of a quantum optical connection device including the ion trap chip according to Embodiment 1.

Mode for Carrying Out the Invention

[0024] In the following description, the "plan view" of a certain configuration means a view of the configuration in a plan view, that is, a view seen from a direction perpendicular to the plate surface of the configuration.

[0025] 〔Embodiment 1〕 FIG. 1 is a cross-sectional view showing a schematic configuration of an ion trap chip 1 according to the present embodiment. The ion trap chip 1 includes an electrode substrate 10 (ion trap electrode substrate), a first optical circuit substrate 300, a magnetic field forming unit 20, and a plurality of spacers 40.

[0026] Ion I is an ion that functions as a quantum bit supplied from the outside of the ion trap chip 1. Ion I is, for example, Be + ion, Mg + ion, Ca +Ions, Sr + Ion, Ba + Ions, etc.

[0027] The electrode substrate 10 forms an electric field for holding the ion I, which will become a qubit, in space. The electrode substrate 10 has an insulating substrate 350 and an electrode layer 340. The insulating substrate 350 is a substrate made of an insulator. The electrode layer 340 is a layer on which multiple electrodes are formed. The electrode layer 340 is formed on the insulating substrate 350.

[0028] The first optical circuit board 300 is a substrate on which an optical circuit is formed. The first optical circuit board 300 is positioned opposite the electrode substrate 10, with ions I held in space in between. The first optical circuit board 300 has a first optical transmission layer 310, a second optical transmission layer 320, a first low refractive index layer 331, a second low refractive index layer 332, a third low refractive index layer 333, a substrate portion 351, and a conductive layer 341. The first optical circuit board 300 has a plurality of through holes 94 to 96 formed therein for alignment. The plurality of through holes 94 to 96 penetrate the first optical circuit board 300 in the thickness direction.

[0029] On the substrate portion 351, a first low refractive index layer 331, a second optical transmission layer 320, a second low refractive index layer 332, a first optical transmission layer 310, a third low refractive index layer 333, and a conductive layer 341 are formed in this order.

[0030] The first optical transmission layer 310 is sandwiched between the second low refractive index layer 332 and the third low refractive index layer 333. The first optical transmission layer 310 has an optical circuit for transmitting light, which is made of a material with a higher refractive index than the second low refractive index layer 332 and the third low refractive index layer 333. A light-receiving section, which will be described later, is formed on the first optical transmission layer 310. The first optical transmission layer 310 is located on the ion I side of the substrate portion 351.

[0031] The second optical transmission layer 320 is sandwiched between the first low refractive index layer 331 and the second low refractive index layer 332. The second optical transmission layer 320 has an optical circuit for transmitting light, which is made of a material with a higher refractive index than the first low refractive index layer 331 and the second low refractive index layer 332. A light emission section, which will be described later, is formed in the second optical transmission layer 320. The second optical transmission layer 320 is located on the ion I side of the substrate portion 351.

[0032] The first low refractive index layer 331, the second low refractive index layer 332, and the third low refractive index layer 333 function as cladding surrounding the waveguide (core).

[0033] The substrate portion 351 is the base that supports each layer. The substrate portion 351 may or may not be transparent to the light used.

[0034] The conductive layer 341 is located on the ion I side of the first optical transmission layer 310 and the second optical transmission layer 320. The conductive layer 341 has a conductive film. The conductive film protects the optical circuit from electric field noise caused by the electrode substrate 10. The conductive film is formed in areas other than the light-receiving and light-emitting sections. In particular, the conductive film is formed in areas other than the grating in the light-receiving and light-emitting sections.

[0035] The multiple spacers 40 are spacers that maintain a constant distance between the electrode substrate 10 and the first optical circuit board 300. The multiple spacers 40 are sandwiched between the electrode substrate 10 and the first optical circuit board 300.

[0036] The magnetic field generating unit 20 forms a magnetic field H to hold the ions I at the position where the ions I are held. Here, the magnetic field H is oriented parallel to the electrode substrate 10. The magnetic field generating unit 20 includes an electromagnetic coil, etc. Note that the magnetic field generating unit 20 is schematically depicted in the figure.

[0037] Multiple through holes 91-93 correspond to multiple through holes 94-96, respectively. Multiple pins are inserted into multiple through holes 91-93 and multiple through holes 94-96. This aligns the electrode substrate 10 with the first optical circuit board 300.

[0038] The laser light (light) L emitted from the light emission section of the second optical transmission layer 320 passes through the first optical transmission layer 310, the second low refractive index layer 332, the third low refractive index layer 333, and the conductive layer 341, and is irradiated onto ion I. The fluorescence F emitted from ion I passes through the third low refractive index layer 333 and the conductive layer 341, and is incident on the light receiving section of the first optical transmission layer 310.

[0039] Figure 2 is a plan view showing the configuration of the electrode substrate 10 of the ion trap chip 1 according to this embodiment. The electrode substrate 10 has a plurality of electrodes that constitute a surface electrode trap. Specifically, the electrode substrate 10 has electrodes 11 to 19. The electrode substrate 10 has a plurality of through holes 91 to 93 formed therein for alignment. The plurality of through holes 91 to 93 penetrate the electrode substrate 10 in the thickness direction.

[0040] A DC voltage is applied to electrodes 11-17. An AC voltage is applied to electrodes 18 and 19. The electrode substrate 10 forms an electric field to hold ions I in space due to these DC and AC voltages.

[0041] (Configuration of the first optical transmission layer 310) Figure 3 is a plan view showing the configuration of the first optical circuit board 300. The first optical circuit board 300 includes a light-receiving section 120, a first optical waveguide 110 (optical waveguide), a first spot diameter converter 130, and a first optical fiber 140. The light-receiving section 120, the first optical waveguide 110, and the first spot diameter converter 130 are formed in the first optical transmission layer 310. The light-receiving section 120, the first optical waveguide 110, and the first spot diameter converter 130 are made of materials with a higher refractive index than the surrounding materials. An optical circuit can be formed in the first optical transmission layer 310 by lithography or ultraviolet irradiation.

[0042] The light-receiving unit 120 receives photons from fluorescence F emitted from ion I and introduces the photons into the first optical waveguide 110. The light-receiving unit 120 faces the electrode substrate 10 with the held ion I in between. The light-receiving unit 120 is located in a position corresponding to ion I. For example, in a plan view, the light-receiving unit 120 is located in a position overlapping the held ion I. The light-receiving unit 120 has a first grating 122 and a first connection region 123 (shaping region). For example, the light-receiving unit 120 has a fan shape centered on a first center 121.

[0043] The first grating 122 is a diffraction grating in which multiple arc regions with different refractive indices are arranged concentrically around the first center 121. The first grating 122 is a wide, arc-shaped region. The diffraction focus of the first grating 122 is set to coincide with the position of ion I. That is, the fluorescence F emitted from ion I is efficiently received by the first grating 122 and introduced into the first connection region 123 connected to the first grating 122.

[0044] The first connection region 123 is a region in the light-receiving section 120 where the first grating 122 is not formed. The first connection region 123 is formed between the first grating 122 and the first optical waveguide 110, and connects the first grating 122 and the first optical waveguide 110, which is narrower than the first grating 122. The first connection region 123 shapes the shape (size) of the propagating light (photons). For example, the first connection region 123 is a fan-shaped region extending from the first center 121, which is the connection point with the first optical waveguide 110. The first connection region 123 transmits the photons received by the first grating 122 and introduces the photons into the first optical waveguide 110. The first connection region 123 is not limited to a fan shape, but may be a region having a gradually narrowing width.

[0045] The first optical waveguide 110 is a waveguide for transmitting photons. One end of the first optical waveguide 110 is connected to the first spot diameter converter 130.

[0046] The first spot diameter converter 130 introduces photons transmitted from the first optical waveguide 110 into the first optical fiber 140. The first spot diameter converter 130 converts the spot diameter of the transmitted fluorescence to a spot diameter suitable for the first optical fiber 140.

[0047] The first optical fiber 140 transmits photons to an external device. For example, the first optical fiber 140 transmits photons to a Bell measuring device.

[0048] The center line C of the fan-shaped light-receiving section 120 is inclined obliquely with respect to the direction of the magnetic field H in a plan view. That is, in a plan view, the diffraction gratings constituting the first grating 122 are aligned obliquely with respect to the direction of the magnetic field H. For example, the center line C of the fan-shaped light-receiving section 120 is inclined at 45° with respect to the direction of the magnetic field H in a plan view.

[0049] The polarization direction of the fluorescence F emitted from ion I is either parallel to or perpendicular to the magnetic field H, depending on the quantum state of ion I. Diffraction gratings can hardly receive light with a polarization direction perpendicular to the direction in which the gratings are aligned.

[0050] On the other hand, the first grating 122 can receive both fluorescence F with polarization directions parallel to the magnetic field H and fluorescence F with polarization directions perpendicular to the magnetic field H. Therefore, the light-receiving section 120 can efficiently capture fluorescence F. Consequently, it is not necessary to provide different light-receiving sections for each polarization direction for a single ion I. Therefore, the area of ​​the light-receiving section 120 can be increased, and the photon collection efficiency can be improved.

[0051] (Configuration of the second optical transmission layer 320) The first optical circuit board 300 has multiple sets of light-emitting sections 220, second optical waveguides 210, second spot diameter converters 230, and second optical fibers 240. The light-emitting sections 220, second optical waveguides 210, and second spot diameter converters 230 are formed in the second optical transmission layer 320. The light-emitting sections 220, second optical waveguides 210, and second spot diameter converters 230 are made of materials with a higher refractive index than the surrounding materials. Optical circuits can be formed in the second optical transmission layer 320 by lithography or ultraviolet irradiation.

[0052] The second optical fiber 240 transmits laser light L introduced from an external light source (not shown) and introduces the laser light L into the second spot diameter converter 230. Multiple second optical fibers 240 may transmit laser light L of different wavelengths from each other.

[0053] The second spot diameter converter 230 introduces the laser light L transmitted from the second optical fiber 240 into the second optical waveguide 210. The second spot diameter converter 230 converts the spot diameter of the transmitted laser light L to a spot diameter suitable for the second optical waveguide 210.

[0054] The second optical waveguide 210 is a waveguide for transmitting laser light L. One end of the second optical waveguide 210 is connected to the second spot diameter converter 230. The other end of the second optical waveguide 210 is connected to the second center 221 of the light emission unit 220. The second optical waveguide 210 introduces laser light L into the light emission unit 220.

[0055] The light-emitting section 220 irradiates the ions I with laser light L introduced from the second optical waveguide 210. The light-emitting section 220 faces the electrode substrate 10 with the held ions I in between. The light-emitting section 220 has a second grating 222 and a second connection region 223. For example, the light-emitting section 220 has a fan shape centered on the second center 221.

[0056] The second grating 222 is a diffraction grating in which multiple arc regions with different refractive indices are arranged concentrically around the second center 221. The second grating 222 is a wide, arc-shaped region. The focal point of diffraction from the second grating 222 is set to coincide with the position of ion I. That is, the laser light L emitted from the second grating 222 is focused at the position of ion I.

[0057] The second connection region 223 is a region in the light emission section 220 where the second grating 222 is not formed. The second connection region 223 is formed between the second grating 222 and the second optical waveguide 210, and connects the second grating 222 and the second optical waveguide 210, which is narrower than the second grating 222. The second connection region 223 shapes the shape (size) of the propagating light (photons). For example, the second connection region 223 is a fan-shaped region spreading from the second center 221, which is the connection point with the second optical waveguide 210. The laser light L introduced from the second optical waveguide 210 propagates through the second connection region 223, spreading out as it enters the second grating 222. The second connection region 223 is not limited to a fan shape; it may also be a region that gradually narrows in width.

[0058] Multiple light-emitting units 220 are arranged around the first grating 122 of the light-receiving unit 120.

[0059] Some of the multiple light-emitting units 220 are positioned so as not to overlap with the light-receiving unit 120 in a plan view. Therefore, it is possible to prevent the laser light L emitted from the light-emitting units 220 from being received by the light-receiving unit 120.

[0060] In a plan view, the second grating 222 of one of the multiple light-emitting units 220 overlaps with the first connection region 123 where the first grating 122 of the light-receiving unit 120 is not formed. The first connection region 123 transmits laser light L. Therefore, even if the second grating 222 that emits laser light L overlaps with the first connection region 123, the light-receiving unit 120 transmits the laser light L without receiving it. This allows the second grating 222 of the light-emitting unit 220 to be positioned closer to the ions I. Also, the light-receiving unit 120 and the light-emitting unit 220 can be formed in a narrow area. Therefore, more sets of light-receiving units 120 and light-emitting units 220 can be formed on the first optical circuit board 300. Thus, the ion trap chip 1 can hold more ions I, i.e., qubits.

[0061] <Operation of Ion Trap Chip 1> When a voltage is applied to electrodes 11-19, the electrode substrate 10 generates a trap potential. The ion trap chip 1 captures ions I using a magnetic field and an electric field. The electrode substrate 10 holds the captured ions I in space, for example, suspended about 100 micrometers above the surface of the electrode substrate 10. The ions I are used as qubits when the ion trap chip 1 is used in a quantum computer, as will be described later.

[0062] The light emission unit 220 irradiates ion I with a laser pulse of a specific wavelength. As a result, electrons in ion I are excited between energy levels with an energy difference corresponding to the wavelength of the laser pulse. Subsequently, when the electrons transition from one specific energy level to a lower specific energy level, ion I emits fluorescence F with a wavelength corresponding to the energy difference between the energy levels.

[0063] The light-receiving unit 120 receives the fluorescence F, collects photons with energy corresponding to the wavelength of the fluorescence F, and introduces them into the first optical waveguide 110. The photons propagate through the first optical waveguide 110 and are introduced into an external device of the ion trap chip 1 via the first optical fiber 140.

[0064] In the configuration of the ion trap chip 1 of this embodiment, the light-receiving unit 120 and the electrode substrate 10 are arranged so as to sandwich the ion I. Therefore, the light-receiving unit 120 can be positioned regardless of the arrangement of electrodes 11 to 19 on the electrode substrate 10. As a result, the area of ​​the light-receiving unit 120 and the first grating 122 can be increased. In addition, the first grating 122 can be positioned closer to the ion I (a position where they overlap in a plan view). Therefore, the photon collection efficiency by the light-receiving unit 120 can be improved. Furthermore, the first optical circuit board 100 having the light-receiving unit 120 and the electrode substrate 10 are separate, and each substrate can be manufactured separately and then superimposed.

[0065] [Embodiment 2] Other embodiments of the present invention are described below. For the sake of clarity, components having the same function as those described in the above embodiments will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0066] Figure 4 is a schematic cross-sectional view showing the configuration of the ion trap chip 2 according to this embodiment. The ion trap chip 2 comprises an electrode substrate 10, a first optical circuit substrate 100, a second optical circuit substrate 200, and a plurality of spacers 40.

[0067] The multiple spacers 40 are spacers that maintain a constant distance between the electrode substrate 10 and the first optical circuit substrate 100. The multiple spacers 40 are sandwiched between the electrode substrate 10 and the first optical circuit substrate 100. The first optical circuit substrate 100 is positioned on the ion I side of the second optical circuit substrate 200. The second optical circuit substrate 200 is positioned on the first optical circuit substrate 100 side of the ion I. The first optical circuit substrate 100 may be in contact with the second optical circuit substrate 200, or it may be separated by spacers or the like.

[0068] (Configuration of the first optical circuit board 100) The first optical circuit board 100 is a substrate on which an optical circuit is formed. The first optical circuit board 100 is positioned opposite the electrode substrate 10, with ions I held in space in between. The first optical circuit board 100 has a first optical transmission layer 310, a first low refractive index layer 102, a second low refractive index layer 103, a first substrate portion 101, and a conductive layer 341. The first optical circuit board 100 has a plurality of through holes 97 to 99 for alignment. The plurality of through holes 97 to 99 penetrate the first optical circuit board 100 in the thickness direction.

[0069] A first low refractive index layer 102, a first optical transmission layer 310, a second low refractive index layer 103, and a conductive layer 341 are formed on the first substrate portion 101 in this order.

[0070] The first optical transmission layer 310 is sandwiched between the first low refractive index layer 102 and the second low refractive index layer 103. The first optical transmission layer 310 is made of a material with a higher refractive index than the first low refractive index layer 102 and the second low refractive index layer 103. The first optical transmission layer 310 is located on the ion I side of the first substrate portion 101.

[0071] The first low refractive index layer 102 and the second low refractive index layer 103 function as cladding surrounding the waveguide (core).

[0072] The first substrate portion 101 is a base that supports each layer. The first substrate portion 101 may or may not be transparent to the fluorescent light F. The first optical circuit board 100 is transparent to the laser light L used.

[0073] The conductive layer 341 is located on the ion I side of the first optical transmission layer 310 and the second optical transmission layer described later. The conductive layer 341 has a conductive film. The conductive film protects the optical circuit from electric field noise caused by the electrode substrate 10. The conductive film is formed in areas other than the light-receiving section and the light-emitting section of the second optical transmission layer described later. In particular, the conductive film is formed in areas other than the grating in the light-receiving section and the light-emitting section.

[0074] (Configuration of the second optical circuit board 200) The second optical circuit board 200 is a substrate on which an optical circuit is formed. The second optical circuit board 200 is positioned opposite the electrode substrate 10, with the ions I and the first optical circuit board 100, which are held in space, in between. The second optical circuit board 200 has a second optical transmission layer 320, a third low refractive index layer 202, a fourth low refractive index layer 203, and a second substrate portion 201. The second optical circuit board 200 has a plurality of through holes 94 to 96 formed therein for alignment. The plurality of through holes 94 to 96 penetrate the second optical circuit board 200 in the thickness direction. The plurality of through holes 94 to 96 correspond to the plurality of through holes 97 to 99 of the first optical circuit board 100, respectively.

[0075] A third low refractive index layer 202, a second optical transmission layer 320, and a fourth low refractive index layer 203 are formed on the second substrate portion 201 in this order.

[0076] The second optical transmission layer 320 is sandwiched between the third low refractive index layer 202 and the fourth low refractive index layer 203. The second optical transmission layer 320 is made of a material with a higher refractive index than the third low refractive index layer 202 and the fourth low refractive index layer 203. The second optical transmission layer 320 is located on the ion I side of the second substrate portion 201.

[0077] The third low refractive index layer 202 and the fourth low refractive index layer 203 function as cladding surrounding the waveguide (core).

[0078] The second substrate portion 201 is a base that supports each layer. The second substrate portion 201 may or may not be transparent to the light used.

[0079] <Operation of Ion Trap Chip 2> The ion trap chip 2 of this embodiment operates in the same manner as the ion trap chip 1 described above. In the ion trap chip 2, the first optical circuit board 100 having a light receiving section 120, the second optical circuit board 200 having a light emitting section 220, and the electrode board 10 are separate, and each board can be manufactured separately and then stacked. The configuration of each optical circuit may be the same as in Embodiment 1.

[0080] [Variation] In each of the above embodiments, the multiple light emission units 220 of the second optical transmission layer 320 may emit laser light L such as a cooling laser or an initialization laser, in addition to the laser pulse that excites the electrons of ion I. The cooling laser is a laser that cools ion I. The initialization laser is a laser pulse that excites the electrons of ion I and returns them to the ground state in order to initialize ion I as a qubit.

[0081] In Embodiment 2, the second optical circuit board 200 may be located on the ion I side of the first optical circuit board 100. In this case, the first optical circuit board 100 is positioned facing the electrode substrate 10, with the ion I held in space and the second optical circuit board 200 in between. In this case, the second optical circuit board 200 is transparent to the fluorescent F.

[0082] In each of the embodiments described above, the case in which the electrode substrate 10 captures one ion I has been explained. In each embodiment, the electrode substrate 10 may capture multiple ions I. In this case, a plurality of light-emitting sections 220 and a plurality of light-receiving sections 120 are formed corresponding to the number of ions that are held.

[0083] Multiple light-receiving units may be provided for a single ion. For example, a light-receiving unit may be provided to receive longitudinally polarized fluorescence F emitted from a single ion, and another light-receiving unit may be provided to receive transversely polarized fluorescence F. In this case, the direction in which the first gratings of one light-receiving unit are aligned may be parallel to the magnetic field, and the direction in which the first gratings of the other light-receiving unit are aligned may be perpendicular to the magnetic field.

[0084] In a plan view, the light-receiving section 120 and all the light-emitting sections 220 may be arranged so as not to overlap with each other.

[0085] In a plan view, the second gratings 222 of all light-emitting sections 220 may overlap the first connection area 123 of the light-receiving section 120.

[0086] (Quantum optical connection device) Figure 5 shows a schematic configuration of a quantum optical connection device equipped with an ion trap chip. The ion trap chips 1 and 2 described above can be used in a quantum computer that uses ions as qubits. In particular, ion trap chips 1 and 2 can be used in a quantum computer that uses multiple ions as qubits and performs quantum information processing using quantum optical connection by the photon interconnection method. The quantum optical connection device when the quantum computer is equipped with a quantum optical connection device that uses the photon interconnection method will be described below.

[0087] The quantum optical connection device comprises an ion trap chip 1a, an ion trap chip 1b, a first connecting optical fiber 3a, a second connecting optical fiber 3b, and a Bell measuring device 4.

[0088] Ion trap chip 1a is ion trap chip 1. Ion trap chip 1a introduces photons received from ions into the first connecting optical fiber 3a.

[0089] Ion trap chip 1b is ion trap chip 1. Ion trap chip 1b introduces photons received from ions into the second connecting optical fiber 3b.

[0090] The first connecting optical fiber 3a transmits photons introduced from the ion trap chip 1a to the Bell measuring device 4.

[0091] The second connecting optical fiber 3b transmits photons introduced from the ion trap chip 1b to the Bell measuring device 4.

[0092] The Bell measurement device 4 performs Bell measurements on the multiple introduced photons.

[0093] In the above examples of use, ion trap tip 1a and / or ion trap tip 1b may be replaced with ion trap tip 2 instead of ion trap tip 1.

[0094] [Additional Notes] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0095] 1, 1a, 1b, 2 Ion trap tips 10 Electrode substrate (ion trap electrode substrate) 20 Magnetic field forming part 100, 300 First optical circuit board 110 First optical waveguide (optical waveguide) 120 Light receiving section 122 First Grating 123 First connection region (shaping region) 200 Second Optical Circuit Board 220 Light-emitting section 222 Second Grating 310 First Optical Transmission Layer 320 Second Optical Transmission Layer 341 Conductive layer Ion H magnetic field L Laser light (light)

Claims

1. An ion trap electrode substrate that holds ions that will become qubits in space, The first optical circuit board includes an optical waveguide and a light receiving unit that receives photons emitted from the ions and introduces the photons into the optical waveguide, The light-receiving unit is an ion trap chip that faces the ion trap electrode substrate with the ions in between.

2. A magnetic field forming unit that forms a magnetic field at the position where the ions are held, The ion trap chip according to claim 1, wherein the light-receiving section has a first grating that is arranged obliquely to the direction of the magnetic field in a plan view.

3. The first optical circuit board is The first optical transmission layer on which the light receiving section is formed, The ion trap chip according to claim 1, comprising a second optical transmission layer having a light-emitting section for irradiating the ions with light.

4. The ion trap chip according to claim 1, further comprising a second optical circuit board having a light emission section formed on the first optical circuit board side of the ion for irradiating the ion with light.

5. The ion trap tip according to claim 3 or 4, wherein, in a plan view, the light receiving portion and the light emitting portion are arranged so as not to overlap with each other.

6. The light-receiving unit has a first grating that receives the photons, The ion trap tip according to claim 3 or 4, wherein the light emitting portion has a second grating that overlaps with the region in the light receiving portion where the first grating is not formed.

7. The light-receiving unit has a shaping region formed between the first grating and the optical waveguide for transmitting the photons, The ion trap tip according to claim 6, wherein the second grating overlaps the shaping region of the light-receiving portion in a plan view.

8. The light-receiving unit has a first grating that receives the photons, The first optical circuit board is The first optical transmission layer on which the light receiving section is formed, The conductive layer is located on the ion side of the first optical transmission layer, The ion trap chip according to claim 1, wherein the conductive layer has a conductive film formed in a region other than the first grating.

Images