Optical tweezers generation system, control device, optical tweezers generation method, control method, program, and quantum computer device

Abstract

This optical tweezers generation system comprises: a plurality of light sources that output laser beams having different wavelengths; a plurality of spatial light modulators that modulate the phases of the respective laser beams; and a lens that condenses the respective phase-modulated laser beams to generate an optical tweezers array on the basis of the respective laser beams.

Description

Optical tweezers generation system, control device, optical tweezers generation method, control method, program, and quantum computer device

[0001] The present invention relates to an optical tweezers generation system, a control device, an optical tweezers generation method, a control method, a program, and a quantum computer device. This application claims priority to Japanese Patent Application No. 2024-178955, filed in Japan on October 11, 2024, the contents of which are incorporated herein by reference.

[0002] There is a technique called optical tweezers, which uses focused laser light to capture tiny particles such as atoms. An array of multiple optical tweezers arranged in a sequence is called an optical tweezers array. Optical tweezers arrays are used, for example, in cold-atom quantum computers to individually capture and arrange multiple atoms. Cold-atom quantum computers are characterized by using laser light to cool an atomic gas and using these as qubits. Optical tweezers are a technique that can be used to trap these cooled atoms.

[0003] When arranging multiple atoms individually using an optical tweezers array, for example, the phase of the laser light irradiated to form the optical tweezers array is controlled by a spatial light modulator, and the light intensity distribution on the focal plane is controlled to become a collection of focal points arranged in an array. Then, each optical tweezers captures an individual atom. By making the central intensity of each optical tweezers uniform, the potential depth for capturing atoms constituting the qubit can be made constant, and the atomic capture probability and the variation in energy differences between the internal states of atoms can be reduced. For example, Non-Patent Literature 1 discloses the uniformization of the central intensity of an optical tweezers array. Non-Patent Literature 2 also discloses the creation of an optical tweezers array of about 14 × 16 with an optical tweezers spacing of 8 micrometers.

[0004] Furthermore, there are methods for arranging atoms in multiple layers using optical tweezers arrays. For example, Patent Document 1 discloses a method for arranging atoms in multiple layers in three-dimensional space by splitting a laser beam into two beams, S-polarized and P-polarized, and driving optical traps generated by each beam. Non-Patent Document 3 discloses a method for forming an optical tweezers array using two lasers with different wavelengths and polarization directions.

[0005] Special Publication No. 2023-526072

[0006] F. Nogrette, H. Labuhn, S. Ravets, D. Barredo, L. Beguin, A. Vernier, T. Lahaye, and A. Browaeys, “Single-Atom Trapping in Holographic 2D Arrays of Microtraps with Arbitrary Geometries”, Phys. Rev. X 4, 021034 Published 23 May 2014Y. Chew, T. Tomita, TP Mahesh, S. Sugawa, S. de Leseleuc & K. Ohmori , “Ultrafast energy exchange between two single Rydberg atoms on a nanosecond timescale”, Nature Photonics 16, 724 (2022). Hannah J. Manetsch, * Gyohei Nomura, * Elie Bataille, * Kon H. Leung, Xudong Lv, and Manuel Endres, “A tweezer array with 6100 highly coherent atomic qubits”, arXiv:2403.12021v2 [quant‐ph] 19 Mar 2024.

[0007] However, the method disclosed in Patent Document 1 uses a laser beam divided into two beams, S-polarized and P-polarized, and can only create a maximum of two layers of optical tweezers arrays. Furthermore, the methods disclosed in Non-Patent Documents 2 and 3 are limited to creating arrays consisting of about 10,000 atoms and cannot create arrays containing more atoms. The object of the present invention is to provide an optical tweezers generation system, control device, optical tweezers generation method, control method, program, and quantum computer device that can create arrays containing more atoms.

[0008] One aspect of the present invention is an optical tweezers generation system comprising: a plurality of light sources that output laser light of different wavelengths; a plurality of spatial light modulators that modulate the phase of each of the laser light; and a lens that generates an optical tweezers array based on each of the phase-modulated laser light by focusing the respective laser light, wherein a plurality of dichroic mirrors that selectively transmit and reflect the plurality of laser light are arranged in the optical path between the spatial light modulator and the lens.

[0009] One aspect of the present invention is a control device for controlling a plurality of optical tweezers array generation devices, wherein each optical tweezers array generation device comprises a light source that outputs laser light and a spatial light modulator that modulates the phase of the laser light, the wavelength of the laser light differs among all the optical tweezers array generation devices, the laser light is output from only one of the plurality of light sources, the spatial light modulator corresponding to the light source that outputs the laser light is controlled, the control of the light source and spatial light modulator is performed sequentially for each optical tweezers array generation device, and a plurality of dichroic mirrors that selectively transmit and reflect the plurality of laser lights are arranged in the optical path between the spatial light modulator and the lens.

[0010] One aspect of the present invention is a method for generating optical tweezers, which involves outputting laser light with different wavelengths, modulating the phase of each of the laser light beams, focusing the phase-modulated laser light beams to generate an optical tweezers array based on each of the laser light beams, and arranging a plurality of dichroic mirrors that selectively transmit and reflect the plurality of laser light beams in the optical path between the spatial light modulator and the lens.

[0011] One aspect of the present invention is a control method for controlling a plurality of optical tweezers array generating devices, wherein each optical tweezers array generating device comprises a light source that outputs laser light and a spatial light modulator that modulates the phase of the laser light, the wavelength of the laser light differs among all the optical tweezers array generating devices, the laser light is output from only one of the plurality of light sources, the spatial light modulator corresponding to the light source that outputs the laser light is controlled, the control of the light source and spatial light modulator is performed sequentially for each optical tweezers array generating device, and a plurality of dichroic mirrors that selectively transmit and reflect the plurality of laser lights are arranged in the optical path between the spatial light modulator and the lens.

[0012] According to the present invention, it is possible to create an array containing more atoms.

[0013] This is a diagram showing the configuration of the optical tweezers generation system 1 according to the first embodiment. This is a flowchart showing the operation of the control device 110 according to the first embodiment. This is a diagram showing the optical tweezers array generated when the focal planes of the light output from each optical tweezers array generation device 20 are on the same plane. This is a diagram showing the configuration of the optical tweezers generation system 1 that can generate dynamic optical tweezers. This is a diagram showing the optical tweezers array generated when the focal planes of the light output from each optical tweezers array generation device 20 are on different planes. This is a diagram showing the configuration of the optical tweezers generation system 1 according to the second embodiment. This is a diagram showing the optical tweezers array generated by the optical tweezers generation system 1 according to the second embodiment. This is a diagram showing an example of the configuration of the interference laser 210. This is a diagram showing an example of the configuration of the optical tweezers generation system 1 according to the first embodiment.

[0014] (First Embodiment) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of an optical tweezer generation system 1 according to the first embodiment. The optical tweezer generation system 1 according to the first embodiment includes a plurality of optical tweezer array generation devices 20-1 to 20-N, a control device 110, a lens 13, and a measurement device 14.

[0015] The optical tweezer array generation device 20 and the lens 13 generate an optical tweezer array for arranging atoms in a two-dimensional plane. The optical tweezer array generation device 20-k (1 ≤ k ≤ N) includes a light source 10-k, a spatial light modulator 11-k, and a mirror 12-k.

[0016] The light source 10 outputs laser light to the spatial light modulator 11. The light sources 10 of each optical tweezer array generation device 20 output laser light of different wavelengths. The number of light sources 10 may be two or more, preferably three or more.

[0017] The spatial light modulator 11 modulates the phase of the input light and outputs the modulated light so as to form a focus at multiple points on the lens 13 via the mirror 12. The phase modulated by the spatial light modulator 11 is set according to the two-dimensional position of the spatial light modulator 11 where the light is input. The control device 110 controls the spatial light modulator 11 and changes the phase of the light output from the spatial light modulator 11.

[0018] The mirror 12 reflects the light input from the spatial light modulator 11 and outputs it to the lens 13. The plurality of mirrors 12-1 to 12-N combine the light modulated by each spatial light modulator 11. For example, the mirror 12-1 is a total reflection mirror, the mirrors 12-2 to 12-N are dichroic mirrors, and the mirror 12-2 combines the laser light reflected by the mirror 12-1 and the laser light incident from the spatial light modulator 11-2 and enters the mirror 12-3. By repeating this, the light modulated by all the spatial light modulators 11 is combined. Note that the mirror 12-1 only needs to be able to reflect the light modulated by the spatial light modulator 11-1 and may be a dichroic mirror.

[0019] The lens 13 finally focuses the light input from the mirror 12 - N. By focusing the light, atoms can be trapped near the focal point. In the optical tweezer generation system 1, a focusing optical system is constituted by a plurality of spatial light modulators 11 - 1 to 11 - N, a plurality of mirrors 12 - 1 to 12 - N, and the lens 13. As a result, an optical tweezer array for arranging atoms in a two-dimensional plane for each light of different wavelengths is generated, and the atoms are trapped.

[0020] The measuring device 14 measures the characteristics of the generated optical tweezer array. The characteristics of the measured optical tweezer array are, for example, the position where atoms are trapped in the optical tweezer array and the vibration frequency of the trapped atoms. The measuring device 14 measures the position where atoms are trapped in the optical tweezer array, for example, by measuring the light intensity distribution of the optical tweezer. Since atoms feel lower energy the stronger the light intensity is, the potential shape is a valley type. As a result, the atoms are trapped in the region where the potential is low. The control device 110 controls each spatial light modulator 11 based on the measurement result by the measuring device 14, changes the phase of the light output from each spatial light modulator 11, and traps the atoms.

[0021] Also, for example, the measuring device 14 includes a measurement light source, a fluorescence observation camera, and a fluorescence analysis unit, and measures the vibration frequency of the atoms by applying the method of Raman sideband spectroscopy to the trapped atoms. More specifically, the measurement light source irradiates the trapped atoms with light of a plurality of frequencies, causing a Raman transition that raises the vibration level by a unit amount. The fluorescence observation camera observes the fluorescence of the trapped atoms, and the fluorescence analysis unit calculates the vibration frequency of the atoms by specifying the raised vibration level of the atoms by measuring the frequency of the observed fluorescence. The vibration frequency of the atoms corresponds to the beam radius and curvature of the light intensity distribution where the atoms are trapped.

[0022] The control device 110 controls the electric field of the light output from each spatial light modulator 11 based on the vibration frequency of the atom A in each optical tweezer. The control device 110 controls, for example, the electric field of the light output from a specific point of each spatial light modulator 11 based on the vibration frequency of the atom A in each optical tweezer.

[0023] Figure 2 is a flowchart showing the operation of the control device 110 according to the first embodiment. The measuring device 14 measures the characteristics of the optical tweezers array generated by one optical tweezers array generation device 20 (step S101). At this time, laser light is output from only one optical tweezers array generation device 20, and no laser light is output from the other optical tweezers array generation device 20. The control device 110 switches whether or not laser light is output from the optical tweezers array generation device 20 by, for example, switching the light source 10 on and off.

[0024] Based on the measurement results, the control device 110 controls the electric field of the light output from the spatial light modulator 11 of the optical tweezers array generation device 20, which emits laser light (step S102). If the control device 110 has performed the control a predetermined number of times (step S103: YES), it performs the operation of step S104, which will be described later. If the control device 110 has not performed the control a predetermined number of times (step S103: NO), it performs the operation of step S101 again. By repeating the above process, the central intensity and curvature of the optical tweezers array generated by one optical tweezers array generation device 20 are controlled.

[0025] If the electric fields of the light output from the spatial light modulators 11 of all optical tweezers array generators 20 are not controlled (step S104: NO), the control device 110 switches the optical tweezers array generator 20 to be controlled (step S105). Here, the control device 110 turns off the light source 10 of the optical tweezers array generator 20 that was being controlled so that laser light is not output from that optical tweezers array generator 20, and turns on the light source 10 of the optical tweezers array generator 20 to be newly controlled so that laser light is emitted from that optical tweezers array generator 20. After that, the measuring device 14 performs the operation of step S101, and the control device 110 performs the operation of S102 to control the electric fields of the light output from the spatial light modulators 11 of the optical tweezers array generator 20 to be controlled.

[0026] If the electric field of the light output from the spatial light modulators 11 of all optical tweezers array generation devices 20 is controlled (step S104: YES), the operation is terminated. In other words, the optical tweezers generation system 1 controls the spatial light modulators 11 of each optical tweezers array generation device 20 one by one through the operations from step S101 to step S105, and adjusts the optical tweezers array generated by each optical tweezers array generation device 20 one by one, thereby enabling the generation of optical tweezers arrays by multiple optical tweezers array generation devices 20.

[0027] The positions of the optical tweezers generated by one optical tweezers array generator 20 do not overlap with the positions of any optical tweezers generated by other optical tweezers array generators 20. The focal planes of the light output from each optical tweezers array generator 20 may be on the same plane or on different planes. When the focal planes of the light output from each optical tweezers array generator 20 are on the same plane, the control device 110 controls the spatial light modulator 11 so that any two atoms arranged by different optical tweezers array generators 20 are separated by a predetermined distance or more. As a result, the atoms are arranged more densely on the same plane.

[0028] Figure 3 shows the optical tweezers arrays generated when the focal planes of the light output from each optical tweezers array generation device 20 are on the same plane. Figure 3 shows optical tweezers arrays 201-1, 201-2, and 201-3 generated by optical tweezers array generation devices 20-1, 20-2, and 20-3 as examples. Optical tweezers arrays 201-1, 201-2, and 201-3 are controlled so that any two atoms placed on the same plane are separated by a predetermined distance or more. The positions of the optical tweezers included in optical tweezers array 201-1 do not overlap with the positions of the optical tweezers included in optical tweezers arrays 201-2 and 201-3. The positions of the optical tweezers included in optical tweezers array 201-2 do not overlap with the positions of the optical tweezers included in optical tweezers arrays 201-1 and 201-3. The positions of the optical tweezers included in optical tweezers array 201-3 do not overlap with the positions of the optical tweezers included in optical tweezers arrays 201-1 and 201-2. In other words, the positions of the optical tweezers included in the optical tweezers array formed based on each laser beam are positioned so as not to overlap with the positions of the optical tweezers included in other optical tweezers arrays formed based on other laser beams. Here, when the positions of the optical tweezers included in the formed optical tweezers array are not displaced, it can be said that a static optical tweezers array can be formed.

[0029] If it is desired to move atoms trapped by a static optical tweezers array to another array, it is necessary to generate dynamic optical tweezers for atom movement operations, separate from the static optical tweezers used for array formation. Figure 4 shows the configuration of an optical tweezers generation system 1 that can generate dynamic optical tweezers. The optical tweezers generation system 1 shown in Figure 5 includes a dynamic tweezers generation device 30 in addition to the optical tweezers generation system 1 according to the first embodiment shown in Figure 1. The dynamic tweezers generation device 30 generates dynamic optical tweezers in a two-dimensional plane. The control device 110 controls the dynamic tweezers generation device 30 and displaces the position of the generated optical tweezers by controlling the laser light output from the dynamic tweezers generation device 30. The dynamic tweezers generation device 30 includes, for example, a light source 300, a two-dimensional AOD (Acousto-Optic Deflector) 301, and a dichroic mirror 302.

[0030] The light source 300 outputs laser light to the two-dimensional AOD 301. The wavelength of the laser light output by the light source 300 is different from the wavelength of the laser light output by each of the light sources 10 of the optical tweezers array generation device 20. The two-dimensional AOD 301 is created by combining two AODs that have non-parallel directions of sound wave transmission (for example, orthogonal directions). The two-dimensional AOD 301 can output the input laser light in any two-dimensional direction. The dichroic mirror 302 combines the laser light input from the optical tweezers array generation device 20-N and the laser light input from the two-dimensional AOD 301 and outputs it to the lens 13. The control device 110 controls the two-dimensional AOD 301 and changes the direction in which the laser light is output. This generates dynamic optical tweezers.

[0031] By shifting the position of the dynamic tweezers from a position that overlaps with the position of the static tweezers to a position that does not overlap, atoms trapped in the static tweezers can be moved. The position of the dynamic tweezers can also be controlled by the control device 110 based on the measurement results from the measuring device 14, similar to the position of the static tweezers. The position of the dynamic tweezers can be monitored by measuring it with the measuring device 14.

[0032] The configuration of the dynamic tweezers generating device 30 is not limited to that described above. The dynamic tweezers generating device 30 may also control the position of the generated dynamic optical tweezers by controlling the electric field of the laser light using a spatial light modulator.

[0033] Furthermore, when the focal planes of the light output from each optical tweezers array generator 20 are different planes, the atoms are arranged in multiple layers by the optical tweezers arrays generated by each optical tweezers array generator 20. Figure 5 shows the optical tweezers arrays generated when the focal planes of the light output from each optical tweezers array generator 20 are different planes. Figure 5 shows optical tweezers arrays 201-1, 201-2, and 201-3 generated by optical tweezers array generators 20-1, 20-2, and 20-3 as examples. Optical tweezers arrays 201-1, 201-2, and 201-3 are generated in different layers.

[0034] (Second Embodiment) Figure 6 shows the configuration of the optical tweezers generation system 1 according to the second embodiment. In the optical tweezers generation system 1 according to the second embodiment, all of the mirrors 12-1 to 12-N are total reflection mirrors. The other configurations are the same as those of the optical tweezers generation system 1 according to the second embodiment and the optical tweezers generation system 1 according to the first embodiment. In the second embodiment, by arranging the mirrors 12-1 to 12-N in appropriate locations, laser light of different wavelengths is incident on the lens 13 with angular dispersion. This forms an array of optical tweezers separated by wavelength at the focal position of the lens 13. Note that the mirrors 12-1 to 12-N only need to be able to reflect the light modulated by the corresponding spatial light modulator 11, and may be dichroic mirrors. Also, the light sources 10-1 to 10-N shown in Figure 6 may output laser light of different wavelengths, or they may output laser light of the same wavelength. If light sources 10-1 to 10-N output laser light of the same wavelength, the laser light output from one light source 10 may be split, and the split laser light may pass through spatial light modulators 11-1 to 11-N and then be incident on mirrors 12-1 to 12-N.

[0035] Figure 7 shows the optical tweezers array generated by the optical tweezers generation system 1 according to the second embodiment. In Figure 7, the wavelength of the laser light output from the optical tweezers array generation device 20-1 is denoted as λ1, the wavelength of the laser light output from the optical tweezers array generation device 20-2 is denoted as λ2, and the wavelength of the laser light output from the optical tweezers array generation device 20-3 is denoted as λ3. By having each laser light incident on the lens 13 at different angles, optical tweezers arrays can be generated separately on the same plane. Figure 7 shows optical tweezers array 201-1 generated by the laser light with wavelength λ1, optical tweezers array 201-2 generated by the laser light with wavelength λ2, and optical tweezers array 201-3 generated by the laser light with wavelength λ3. In the optical tweezers generation system 1 according to the second embodiment, a plurality of light sources 10 are used as shown in Figure 6, but the number of light sources 10 may be at least two or more, preferably three or more.

[0036] As described above, the optical tweezers generation system 1 according to the first or second embodiment can arrange more atoms in space than conventional systems by generating multiple tweezers arrays using multiple laser beams of different wavelengths. Furthermore, the optical tweezers generation system 1 according to the first or second embodiment uses a dichroic mirror to incident the modulated light output from the light source 10 onto the lens 13. For example, the method disclosed in Non-Patent Document 3 uses a polarizing beam splitter and two laser beams with orthogonal polarization characteristics, but the wavelengths of the laser beams used are required to be the same or very close. Also, the number of usable laser beams is limited to two. Since the optical tweezers generation system 1 according to the first or second embodiment uses a dichroic mirror, there is no restriction on the wavelength of the light output from multiple light sources 10-1 to 10-N (for example, it is possible when N = 10). Therefore, in the first or second embodiment, a large-scale optical tweezers array can be formed using three or more different wavelengths of light.

[0037] The optical tweezers array generated by the optical tweezers generation system 1 according to the first or second embodiment can be used to arrange atoms in a quantum computer. For example, in a cold atom quantum computer, an atomic gas is cooled using laser light and excited to be used as a qubit. By trapping the cooled atoms with the optical tweezers array generated by the optical tweezers generation system 1 according to the first or second embodiment, an array can be formed in which multiple atoms are individually captured.

[0038] In a cold atom quantum computer, adjacent atoms trapped in an optical tweezers array are irradiated with laser light of a different wavelength than the laser light used to cool the atoms, exciting each atom into an electronic state with a large orbital radius (Rydberg state). Atoms excited to the Rydberg state have a long distance between the nucleus (+) and electron (-), resulting in a large electric dipole moment. As a result, the interaction of adjacent Rydberg atoms forms a quantum entanglement state, which is the basis of quantum computation. For example, a narrowband pulsed laser light can be used for this Rydberg excitation. The formed quantum entanglement state corresponds to a superposition state of 0s and 1s in a quantum computer, so the atoms trapped in the optical tweezers array can be used as qubits for quantum operations.

[0039] In the invention described in Patent Document 1, atoms are moved by overlapping the positions of the optical tweezers. Therefore, it is considered that arranging the optical tweezers in positions that do not overlap, based on the invention described in Patent Document 1, cannot be adopted.

[0040] The following describes in detail how the control device 110 controls a single optical tweezers array generation device and how an optical tweezers array is generated. The control device 110 controls the electric field of the light output from the spatial light modulator 11 based on the vibration frequency of the atoms in each optical tweezers. For example, the control device 110 controls the electric field of the light output from a specific point of the spatial light modulator 11 based on the vibration frequency of the atoms in each optical tweezers.

[0041] As the electric field of the light output from the spatial light modulator 11 changes, the oscillation frequency of the atoms in each optical tweezer changes. The control device 110 may repeatedly control the electric field of the light output from the spatial light modulator 11 based on the oscillation frequency of the atoms in each optical tweezer. After controlling the electric field of the light output from the spatial light modulator 11 a predetermined number of times, the control device 110 may stop the control. The control device 110 may stop controlling the electric field of the light output from the spatial light modulator 11 when the oscillation frequency of the atoms in each optical tweezer satisfies a predetermined condition. The case where the oscillation frequency satisfies a predetermined condition means, for example, that the difference between the maximum value and the minimum value of the oscillation frequency of the atoms A in each optical tweezer is smaller than a predetermined value. Thus, when the measured oscillation frequency is within a predetermined condition, that is, when the difference between the maximum value and the minimum value of the oscillation frequency is smaller than a predetermined value, it means that the curvature of the light intensity distribution is within a predetermined range.

[0042] For example, the control device 110 calculates the electric field A ｓ , y ｓ of the light output from the point (x ＳＬＭ , y ｓ , y ｓ of the spatial light modulator 11 according to, for example, Equation (1), and controls the phase of the electric field of the light output from the point (x ｓ , y ｓ to be the same as the phase of the calculated electric field A ＳＬＭ , y ｓ , y ｓ .

[0043] In Equation (1), m is the number of optical tweezers generated by the optical tweezer generation system 1. The control device 110 calculates the sum of the intensities of the light output from the points (x ｓ , y ｓ necessary for generating each optical tweezer on the right side of Equation (1), and thereby calculates the intensity A ｓ , y ｓ of the light output from the point (x ＳＬＭ , y ｓ , y ｓ necessary for generating m optical tweezers.

[0044] In equation (1), w ｘ、ｍ and w ｙ、ｍ This is a curvature adjustment value corresponding to the vibration frequency of atom A captured by each pair of tweezers. For example, w ｘ、ｍ This is a curvature adjustment value corresponding to the vibration frequency of atom A in the x direction, and w ｙ、ｍ This is a curvature adjustment value corresponding to the vibration frequency of atom A in the y direction. When the vibration frequency of atom A in the x direction is smaller than a predetermined value, the control device 110 controls w ｘ、ｍ The size is increased. Also, if the vibration frequency of atom A in the x direction is greater than a predetermined value, w ｘ、ｍ The size is reduced. The control device 110 is w ｘ、ｍ The adjustment is performed for each individual optical tweezers. The control device 110 does the same for the y-direction as well. ｙ、ｍ The control device 110 adjusts the w in each optical tweezers. ｘ、ｍ and w ｙ、ｍ After adjusting, the light intensity A ＳＬＭ (x ｓ , y ｓ This calculates the curvature of each individual optical tweezers.

[0045] a ｍ This is an amplitude adjustment value that is adjusted so that the central intensity of each optical tweezers is constant. The control device 110 adjusts the electric field amplitude at the center position of each optical tweezers to be constant. ｍ This is adjusted. As a result, the control device 110 can maintain a constant magnitude of the central intensity of the optical tweezers even after adjusting the curvature of the optical tweezers.

[0046] Δ ｍ (x ｓ , y ｓ ) is the point (x) that generates the optical tweezers m. ｓ , y ｓ This is the phase of the light emitted from ). ｍ This is a phase added to prevent interference between optical tweezers.

[0047] As described above, the control device 110 can equalize the central intensity and curvature of the optical tweezers array generated from one optical tweezers array generation device 20. As described above, the control device 110 controls all optical tweezers array generation devices 20 one by one, and equalizes the central intensity and curvature of the optical tweezers array generated from each optical tweezers array generation device 20.

[0048] Furthermore, the control device 110 aligns the optical tweezers array to a desired position in the Z direction perpendicular to the x and y directions. For example, the measuring device 14 is equipped with an interference laser 210, which irradiates the XY plane, created by the x and y directions in which the atoms are positioned, with two laser beams obliquely from above and below in the Z direction. The interference laser 210, the fluorescence observation camera, and the fluorescence analyzer calculate the position of the atoms in the Z direction using two-beam interferometry.

[0049] The interference laser 210 irradiates the XY plane on which atoms are arranged with two laser beams, one from above and one from below in the Z direction, at an oblique angle. The irradiation of the laser beams generates an interference fringe intensity pattern that spreads uniformly along the XY plane and whose intensity changes periodically in the Z direction. When atoms are irradiated with laser beams, they absorb the laser light and emit fluorescence. Atoms irradiated with high-intensity laser light emit strong fluorescence, while atoms irradiated with low-intensity laser light emit weak fluorescence. When the interference fringe intensity pattern is scanned in the Z direction, fluorescence is generated from the atoms in accordance with the change in the intensity of the interference fringes. Therefore, by synchronizing the Z-direction component of the interference fringe intensity pattern with the fluorescence from the atoms, the position of the atoms in the Z direction can be calculated.

[0050] For example, consider the case where an atom A is slightly shifted in the Z direction compared to other atoms. When the maximum intensity pattern of the interference fringes is at Z = 0, the fluorescence from the other atoms is at its maximum, and the fluorescence from atom A is reduced to 1 / a compared to the fluorescence from the other atoms. On the other hand, when the maximum intensity pattern of the interference fringes is at Z = ΔL, the fluorescence from atom A is at its maximum, and the fluorescence from the other atoms is reduced to 1 / a compared to the fluorescence from atom A. In this case, it is calculated that atom A is shifted by ΔL in the Z direction compared to the other atoms.

[0051] The interference laser 210 scans the interference fringe intensity pattern in the Z direction, and the fluorescence observation camera and fluorescence analyzer measure the intensity of the changing interference fringes. By synchronizing the Z-direction position scanned by the interference laser 210 with the interference fringe intensity measured by the fluorescence observation camera and fluorescence analyzer, the Z-direction position of atom A is calculated. The fluorescence observation camera and fluorescence analyzer may measure not only the vibration frequency of the atom but also the Z-direction position of the atom.

[0052] The interference laser 210 splits the laser beam output from the laser source into two and adjusts the direction of each laser beam. Figure 8 shows an example of the configuration of the interference laser 210. The interference laser 210 comprises a laser source 220, a PBS (Polarizing Beam Splitter) 230, a piezo controller 240, mirrors M1-2, and waveplates P1-3. The laser source 220 outputs laser light. The laser light output from the laser source 220 is reflected by mirror M1 and split into two laser beams by the PBS 230. One laser beam is reflected by mirror M2 and output to the array of atoms A, and the other laser beam is output directly to the array of atoms A. The angle of mirror M2 is controlled by the piezo controller 240 to adjust the position where the interference fringe intensity pattern is formed by the irradiation of the laser light. Waveplates P1-3 are provided in the path of the laser light, and the polarization state of the laser light is changed.

[0053] The control device 110 controls the electric field of the light output from the spatial light modulator 11 based on the vibration frequency of atom A in each optical tweezers, as well as the position of the atom in the Z direction.

[0054] As the electric field of the light output from the spatial light modulator 11 changes, the vibration frequency and position in the Z direction of each optical tweezers change. The control device 110 may repeatedly control the electric field of the light output from the spatial light modulator 11 based on the vibration frequency and position in the Z direction of each optical tweezers. After controlling the electric field of the light output from the spatial light modulator 11 a predetermined number of times, the control device 110 may stop the control. The control device 110 may stop controlling the electric field of the light output from the spatial light modulator 11 if the vibration frequency and position in the Z direction of each optical tweezers satisfy predetermined conditions. The condition that the vibration frequency satisfies predetermined conditions means, for example, that the difference between the maximum and minimum values ​​of the vibration frequency of atom A in each optical tweezers is smaller than a predetermined value and / or the maximum value of the difference in position in the Z direction is smaller than a predetermined value.

[0055] The control device 110, for example, uses equation (2), which is obtained by adding a factor indicating a shift in the Z direction to equation (1), to determine the point (x) of the spatial light modulator 11. ｓ , y ｓ The electric field A of light output from ) ＳＬＭ (x ｓ , y ｓ ) calculate the point (x ｓ , y ｓ The phase of the electric field of the light output from ) is calculated as electric field A ＳＬＭ (x ｓ , y ｓ Control it so that it is the same as the phase of ).

[0056] In equation (2), λ, f, z ｍ The definitions of the letters other than π are the same as in equation (1). In equation (2), λ is the wavelength of the laser light output by the interference laser 210. f is the effective focal length from the spatial light modulator 11 to the arrangement of atoms A. ｍ π represents the z-direction position of each atom A captured by the optical tweezers. π is the ratio of a circle's circumference to its diameter (pi).

[0057] As a result, the optical tweezers array is aligned to the desired position in the Z direction.

[0058] Figure 9 shows an example of the configuration of the optical tweezers generation system 1 according to the first embodiment. The optical tweezers generation system 1 according to the first embodiment shown in Figure 9 is equipped with a mirror 12-(N+1) in addition to the optical tweezers generation system 1 shown in Figure 1. Mirror 12-(N+1) reflects the light output from mirrors 12-1 to 12-N and outputs it to the lens 13. Mirror 12-(N+1) is a dichroic mirror, and the fluorescence generated in the trapped atom passes through the lens 13 and is transmitted to the opposite side of the lens 13 at mirror 12-(N+1). The measuring device 14 includes a fluorescence observation camera 120, a fluorescence analyzer 130, a measuring light source 140, and an interference laser 210. The measuring light source 140 incidents light of multiple frequencies onto the trapped atom A, causing a Raman transition that raises the vibrational level by a unit amount. The fluorescence observation camera 120 is provided on the opposite side of the lens 13, with mirror 12-(N+1) in between. The fluorescence observation camera 120 observes the fluorescence of captured atom A. The fluorescence analyzer 130 identifies the elevated vibrational level of the atom by measuring the frequency of the observed fluorescence. This allows the vibrational frequency of the atom to be calculated.

[0059] In the second embodiment as well, the devices of the measuring device 14, the mirror 12-(N+1), and the lens 13 may be arranged as shown in Figure 9.

[0060] (Example 1) The following describes an example of an optical tweezers generation system. Light sources 10-1, 10-2, and 10-3 were laser light sources with wavelengths of 850 nm, 860 nm, and 870 nm, respectively. 800 x 600 pixel liquid crystal type spatial light modulators were used as spatial light modulators 11-1, 11-2, and 11-3.

[0061] As mirror 12-1, a total reflection mirror with a reflectance of 99% at a wavelength of 850 nm was used. As dichroic mirror 12-2, a mirror with a transmittance of 90% at a wavelength of 850 nm and a reflectance of 95% or more at a wavelength of 860 nm was used. As dichroic mirror 12-3, a mirror with a transmittance of 90% at both wavelengths of 850 nm and 860 nm and a reflectance of 95% or more at a wavelength of 870 nm was used.

[0062] The control device 110 controls the point (x) of each spatial light modulator 11 according to equation (1). ｓ , y ｓ The electric field of light output from ) ASLM(x ｓ , y ｓ The spatial light modulator 11 was controlled to calculate the ) and output the calculated electric field of the light. A lens 13 with an NA of 0.75 was used.

[0063] The measurement device 14 was equipped with a fluorescence observation camera with high sensitivity in the visible light range and a laser beam with a wavelength of 795 nm. The trap frequency corresponding to the energy transition of atoms was analyzed using Raman sideband spectroscopy. Furthermore, the alignment of the optical tweezers on a single plane was monitored, for example, by two-beam interferometry.

[0064] The target atom for capture was rubidium (Rb). By filling a vacuum chamber maintained at room temperature with Rb atoms, the Rb atoms could be captured by the optical tweezers array generated by the optical tweezers generation system 1 configured as described above.

[0065] The optical tweezers generation system 1 was able to form an optical tweezers array consisting of 50 x 100 units, and the optical tweezers arrays formed by laser light sources with wavelengths of 850 nm, 860 nm, and 870 nm could be arranged in a multilayer structure with a spacing of 5 μm in the direction of laser propagation.

[0066] <Other Embodiments> Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to that described above, and various design changes can be made without departing from the spirit of the present invention.

[0067] The optical tweezers in this embodiment capture atoms, but the targets of capture are not limited to atoms. For example, minute particles such as nanoparticles or bacteria may also be targets. The atoms are particularly neutral atoms.

[0068] In this embodiment, atomic vibrations are measured using a fluorescence observation camera and a fluorescence analyzer, but the method of measuring vibrations is not limited to this. For example, vibrations may be measured from the intensity distribution of an optical tweezers array captured by the camera or from scattered light from captured minute particles.

[0069] The control device 110 in the above-described embodiment may be implemented in whole or in part by a computer. In that case, the program for implementing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be loaded into a computer system and executed. Here, "computer system" includes the OS and peripheral hardware. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, and recording devices such as hard disks built into a computer system. In addition, "computer-readable recording medium" may include those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside a computer system that acts as a server or client in that case. Furthermore, the above-mentioned program may be for implementing a part of the above-mentioned function, and may also be able to implement the above-mentioned function in combination with a program already recorded in the computer system. Furthermore, the control device 110 may be implemented in whole or in part using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0070] According to the present invention, it is possible to create an array containing more atoms.

[0071] 1 Optical tweezers generation system, 10 Light source, 11 Spatial light modulator, 110 Control device, 12 Mirror, 13 Lens, 14 Measuring device, 20 Optical tweezers array generation device

Claims

1. An optical tweezers generation system comprising: a plurality of light sources that output laser light of different wavelengths; a plurality of spatial light modulators that modulate the phase of each of the laser light beams; and a lens that generates an optical tweezers array based on each of the phase-modulated laser light beams by focusing the respective laser light beams, wherein a plurality of dichroic mirrors that selectively transmit and reflect the plurality of laser light beams are arranged in the optical path between the spatial light modulators and the lens.

2. The optical tweezers generation system according to claim 1, wherein the positions of the optical tweezers included in the static optical tweezers array formed based on each of the laser beams are arranged in positions that do not overlap with the positions of the optical tweezers included in other static optical tweezers arrays formed based on other laser beams.

3. The optical tweezers generation system according to claim 1 or 2, further comprising: a measuring device for measuring the characteristics of the generated optical tweezers array; and a control device for controlling the spatial light modulator based on the measurement results from the measuring device.

4. The optical tweezers generation system according to claim 1 or 2, wherein the focal planes of each laser beam formed by the lens are on the same plane.

5. The optical tweezers generation system according to claim 1 or 2, wherein the focal planes of each laser beam formed by the lens are different planes.

6. The optical tweezers generation system according to claim 1 or 2, wherein the number of the plurality of light sources is three or more.

7. The optical tweezers generation system according to claim 1 or 2, further comprising: a dynamic tweezers generation device that generates light for generating a dynamic optical tweezers array.

8. An optical tweezers generation system comprising: a plurality of light sources that output laser light; a plurality of spatial light modulators that modulate the phase of each of the laser light beams; and a lens that generates an optical tweezers array based on each of the phase-modulated laser light beams by focusing the respective laser light beams, wherein a mirror that reflects the laser light is placed in the optical path between the spatial light modulator and the lens, and the laser light is incident on the lens with angular dispersion.

9. The optical tweezers generation system according to claim 8, wherein the number of the plurality of light sources is three or more.

10. A control device for controlling a plurality of optical tweezers array generating devices, wherein each optical tweezers array generating device comprises: a light source that outputs laser light; and a spatial light modulator that modulates the phase of the laser light, the wavelength of the laser light differs among all the optical tweezers array generating devices; the device outputs laser light from only one of the plurality of light sources; controls the spatial light modulator corresponding to the light source that outputs the laser light; controls the light source and spatial light modulator sequentially for each optical tweezers array generating device; and a plurality of dichroic mirrors that selectively transmit and reflect the plurality of laser lights are arranged in the optical path between the spatial light modulator and the lens.

11. A control device for controlling a plurality of optical tweezers array generation devices, wherein each optical tweezers array generation device comprises a light source that outputs laser light, and a spatial light modulator that modulates the phase of the laser light, the wavelength of the laser light differs among all the optical tweezers array generation devices, the device outputs laser light from only one of the plurality of light sources, controls the spatial light modulator corresponding to the light source that outputs the laser light, controls the light source and spatial light modulator sequentially for each optical tweezers array generation device, and a mirror corresponding to each spatial light modulator and reflecting each laser light is arranged in the optical path between the spatial light modulator and the lens.

12. A method for generating optical tweezers, comprising: outputting laser light with different wavelengths; modulating the phase of each of the laser light beams; focusing the phase-modulated laser light beams to generate an optical tweezers array based on each of the laser light beams; and selectively transmitting and reflecting the laser light beams through a dichroic mirror in the optical path between modulation and focusing.

13. A method for generating optical tweezers, comprising: outputting laser light with different wavelengths; modulating the phase of each of the laser light beams; focusing the phase-modulated laser light beams to generate an optical tweezers array based on each of the laser light beams; and reflecting the laser light beams by mirrors in the optical path between modulation and focusing, and angularly dispersing the laser light beams with respect to a lens that focuses the laser light beams.

14. A control method for controlling multiple optical tweezers array generating devices, wherein each optical tweezers array generating device comprises: a light source that outputs laser light; and a spatial light modulator that modulates the phase of the laser light, the wavelength of the laser light differs among all the optical tweezers array generating devices; laser light is output from only one of the multiple light sources; the spatial light modulator corresponding to the light source that outputs the laser light is controlled; the control of the light source and spatial light modulator is performed sequentially for each optical tweezers array generating device; and a plurality of dichroic mirrors that selectively transmit and reflect the plurality of laser lights are arranged in the optical path between the spatial light modulator and the lens.

15. A control method for controlling multiple optical tweezers array generating devices, wherein each optical tweezers array generating device comprises: a light source that outputs laser light; and a spatial light modulator that modulates the phase of the laser light; the wavelength of the laser light differs among all the optical tweezers array generating devices; laser light is output from only one of the multiple light sources; the spatial light modulator corresponding to the light source that outputs the laser light is controlled; the control of the light source and spatial light modulator is performed sequentially for each optical tweezers array generating device; and mirrors corresponding to each spatial light modulator and reflecting each laser light are arranged in the optical path between the spatial light modulator and the lens.

16. A program that causes a computer to execute the control method described in claim 14 or 15.

17. A quantum computer device using neutral atoms, wherein the neutral atoms are trapped by an array of optical tweezers generated by the optical tweezers generation system according to claim 1 or 8.

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