Solid state quantum storage device
By using a combination of rare-earth-doped crystals and polarization rotators in a solid-state quantum storage device, the storage of multi-polarization state signal light was achieved, solving the problem that existing technologies can only store single polarization states and expanding the applicability of quantum storage.
Patent Information
- Application Number
- CN202423283564.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-12-30
AI Technical Summary
Existing solid-state quantum memories can only store a single polarization state and cannot store photons encoded with arbitrary polarization, which limits the development of quantum computing and quantum networks.
A solid-state quantum storage device is employed, comprising a laser generation module, a pump light modulation mode, a storage light modulation mode, and a phase group connected together. This is achieved through a first rare-earth-doped crystal rotator, a second polarization rotator, a second rare-earth-doped crystal, a second rare-earth-doped crystal, and a second polarization rotator. The first rare-earth-doped crystal absorbs and stores photons in a horizontally polarized state, while photons in a vertically polarized state are converted to a horizontally polarized state approximately without loss through the first polarization rotator, and then absorbed and stored by the second rare-earth-doped crystal. Upon release, the polarization state of the photons is restored through the second polarization rotator.
This technology enables the storage of signal light in multiple polarization states, solving the problem that existing technologies can only store signals in a single polarization state, and expanding the applicability of quantum storage.
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Figure CN223612102U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to quantum storage device and quantum computing field, concretely relates to a solid quantum storage device. BACKGROUND
[0002] Quantum key distribution (QKD) is a unconditional secure communication mode based on physics principle. At present, due to the channel loss that cannot be overcome, the transmission distance of photon as quantum communication carrier is very limited, and it is difficult to realize long-distance quantum communication.
[0003] Quantum computing (QC) as a brand-new computing mode is gradually emerging, and it is a new computing mode that can break through the bottleneck of classical computing power. Therefore, people propose to store photons into quantum storage with long life first, and then use classical transport means to transport quantum encryption storage device to realize long-distance transmission of photons. At present, the solid quantum storage based on rare earth ions is commonly used. However, most of the rare earth doped crystals have anisotropic absorption characteristics, and the single crystal can only store a special polarization state, and cannot realize the storage of photons with arbitrary polarization coding. It is the key technology of quantum computing and quantum network.
[0004] Polarization is the most convenient and stable degree of freedom for photon to carry information. However, due to the anisotropic absorption characteristics of the crystal, the existing solid quantum storage device is preselected for single polarization state input photon, and only single polarization state storage can be realized. UTILITY MODEL CONTENT
[0005] The utility model discloses a solid quantum storage device to solve the problem that the existing solid quantum storage device can only realize single polarization state storage.
[0006] In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows:
[0007] A solid quantum storage device, comprising a laser generation module, a pump light modulation module, a storage light modulation module and a quantum storage module;
[0008] The quantum storage module comprises a first rare earth doped crystal, a first polarization rotator, a second rare earth doped crystal and a second polarization rotator connected in sequence;
[0009] The output end of the laser generation module is connected with the input end of the pump light modulation module and the input end of the storage light modulation module respectively, and the output end of the pump light modulation module and the output end of the storage light modulation module are connected with the input end of the first rare earth doped crystal respectively.
[0010] In the above scheme, during storage, the photons in horizontal polarization state are stored by the first rare-earth doped crystal, and the photons in vertical polarization state pass through the first rare-earth doped crystal approximately without loss, are converted into horizontal polarization state by the first polarization rotator, and are stored by the second rare-earth doped crystal; during release, the polarization states of the photons released by the first rare-earth doped crystal and the second rare-earth doped crystal are recovered by the second polarization rotator; thus, the storage of the multi-polarization state signal light is realized.
[0011] Preferably, the quantum storage module further comprises a focusing lens; the output end of the pump light modulation module and the output end of the storage light modulation module are connected with the input end of the first rare-earth doped crystal through the focusing lens respectively.
[0012] Preferably, the laser generation module comprises a laser, a polarizer and a beam splitter.
[0013] The output end of the laser is connected with the input end of the polarizer, the output end of the polarizer is connected with the first port of the beam splitter, the second port of the beam splitter is connected with the input end of the pump light modulation module, and the third port of the beam splitter is connected with the input end of the storage light modulation module.
[0014] Preferably, the pump light modulation module comprises a first acousto-optic modulator and an intensity modulator.
[0015] The second port of the beam splitter is connected with the input end of the first acousto-optic modulator, the output end of the first acousto-optic modulator is connected with the input end of the intensity modulator, and the output end of the intensity modulator is connected with the input end of the first rare-earth doped crystal through the focusing lens.
[0016] Preferably, the storage light modulation module comprises a second acousto-optic modulator, an attenuator and a polarization controller.
[0017] The third port of the beam splitter is connected with the input end of the second acousto-optic modulator, the output end of the second acousto-optic modulator is connected with the input end of the attenuator, the output end of the attenuator is connected with the input end of the polarization controller, and the output end of the polarization controller is connected with the input end of the first rare-earth doped crystal through the focusing lens.
[0018] Preferably, the quantum storage module further comprises a phase plate.
[0019] The output end of the second rare-earth doped crystal is connected with the input end of the phase plate, and the output end of the phase plate is connected with the input end of the second polarization rotator.
[0020] Preferably, the quantum storage module further comprises a polarization analyzer.
[0021] The output end of the second polarization rotator is connected with the input end of the polarization analyzer.
[0022] Preferably, the first polarization rotator is a first half-wave plate.
[0023] Preferably, the second polarization rotator is a second half-wave plate.
[0024] Preferably, the angle between the fast axis of the second half-wave plate and the x-axis is 45°.
[0025] Beneficial technical effects of the present application:
[0026] The utility model provides a solid state quantum storage device, at storage time, through first rare earth doped crystal to horizontal polarization state's photon carries out absorption storage, and vertical polarization state's photon passes through first rare earth doped crystal after approximately lossless and converts into horizontal polarization state by first polarization rotator, then by second rare earth doped crystal carries out absorption storage, at release, through second polarization rotator restores the polarization state of the photon of first rare earth doped crystal and second rare earth doped crystal release, thereby realized the storage of multi-polarization state signal light. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 It is the whole structure schematic diagram of the utility model;
[0028] Among them: 1, laser generation module;11, laser;12, polarizer;13, beam splitter;2, pump light modulation module;21, first acousto-optic modulator;22, intensity modulator;3, storage light modulation module;31, second acousto-optic modulator;32, attenuator;33, polarization controller;4, quantum storage module;41, first rare earth doped crystal;42, first polarization rotator;43, second rare earth doped crystal;44, second polarization rotator;45, phase plate;46, polarization analyzer;47, light absorption box;5, lens. DETAILED DESCRIPTION
[0029] In order to make the purpose, technical scheme and advantage of the utility model more clearly, the following embodiment is further detailed to the utility model, but the scope of protection required by the utility model is not limited to the following specific embodiments.
[0030] Embodiment 1
[0031] As Figure 1 Indicated, a kind of solid state quantum storage device, including laser generation module 1, pump light modulation module 2, storage light modulation module 3 and quantum storage module 4;
[0032] The quantum storage module 4 includes first rare earth doped crystal 41, first polarization rotator 42, second rare earth doped crystal 43 and second polarization rotator 44 connected in sequence;
[0033] The output end of the laser generation module 1 is connected with the input end of the pump light modulation module 2 and the input end of the storage light modulation module 3 respectively, and the output end of the pump light modulation module 2 and the output end of the storage light modulation module 3 are connected with the input end of the first rare earth doped crystal 41 respectively.
[0034] In the specific implementation process, during storage, the photons in the horizontal polarization state are absorbed and stored by the first rare earth doped crystal 41, and the photons in the vertical polarization state pass through the first rare earth doped crystal 41 approximately without loss, are converted into the horizontal polarization state by the first polarization rotator 42, and are then absorbed and stored by the second rare earth doped crystal 43; during release, the polarization states of the photons released by the first rare earth doped crystal 41 and the second rare earth doped crystal 43 are restored by the second polarization rotator 44; thereby the storage of the multi-polarization state signal light is realized.
[0035] Embodiment 2
[0036] A solid-state quantum storage device, comprising a laser generation module 1, a pump light modulation module 2, a storage light modulation module 3 and a quantum storage module 4.
[0037] The quantum storage module 4 comprises a first rare earth doped crystal 41, a first polarization rotator 42, a second rare earth doped crystal 43 and a second polarization rotator 44 connected in sequence.
[0038] In the specific implementation process, the first rare earth doped crystal 41 and the second rare earth doped crystal 43 have strong absorption to the horizontal polarization component of the photons, and have no absorption to other polarization states, which can be approximately regarded as passing through without loss.
[0039] More specifically, it further comprises a focusing lens 5; the output end of the pump light modulation module 2 and the output end of the storage light modulation module 3 are connected with the input end of the first rare earth doped crystal 41 through the focusing lens 5 respectively.
[0040] In the specific implementation process, the pump light and the signal light to be stored are focused on the quantum storage module 4 by the focusing lens 5; in the optical path setting, the pump light reaches the quantum storage module 4 earlier than the signal light to be stored.
[0041] More specifically, the laser generation module 1 comprises a laser 11, a polarizer 12 and a beam splitter 13.
[0042] The output end of the laser 11 is connected with the input end of the polarizer 12, the output end of the polarizer 12 is connected with the first port of the beam splitter 13, the second port of the beam splitter 13 is connected with the input end of the pump light modulation module 2, and the third port of the beam splitter 13 is connected with the input end of the storage light modulation module 3.
[0043] In the specific implementation process, the laser 11 is used to generate continuous laser with continuous tunable multi-frequency;
[0044] The polarizer 12 is used to modulate the continuous laser emitted by the laser 11 into a 45-degree polarization state of H+V, so as to provide two-component polarization states for the pump light; H represents a horizontal polarization state, and V represents a vertical polarization state.
[0045] The beam splitter 13 is used to split the continuous laser output by the polarizer 12 into two light paths, one of which inputs the pump light modulation module 2, and the other of which inputs the storage light modulation module 3.
[0046] More specifically, the pump light modulation module 2 comprises a first acousto-optic modulator 21 and an intensity modulator 22.
[0047] The second port of the beam splitter 13 is connected with the input end of the first acousto-optic modulator 21, the output end of the first acousto-optic modulator 21 is connected with the input end of the intensity modulator 22, and the output end of the intensity modulator 22 is connected with the input end of the first rare earth doped crystal 41 through the focusing lens 5.
[0048] In the specific implementation process, the acousto-optic modulator with appropriate center frequency parameters is selected as the first acousto-optic modulator 21, which is used to modulate the continuous laser with continuous tunable multi-frequency into a periodic pulse pair in the time domain, and the energy spectrum of the pulse pair corresponds to the frequency comb structure of one period of the quantum storage module 4, so that the pump light can efficiently operate the energy level of the quantum storage module 4; then the pump light is modulated to appropriate intensity by the intensity modulator 22, so that the operation efficiency of the pump light on the energy level of the quantum storage module 4 is maximized.
[0049] More specifically, the storage light modulation module 3 comprises a second acousto-optic modulator 31, an attenuator 32 and a polarization controller 33.
[0050] The third port of the beam splitter 13 is connected with the input end of the second acousto-optic modulator 31, the output end of the second acousto-optic modulator 31 is connected with the input end of the attenuator 32, the output end of the attenuator 32 is connected with the input end of the polarization controller 33, and the output end of the polarization controller 33 is connected with the input end of the first rare earth doped crystal 41 through the focusing lens 5.
[0051] In the specific implementation process, the acousto-optic modulator with appropriate center frequency parameters is selected as the second acousto-optic modulator 31, which is used to modulate the signal light to be stored according to the continuous laser with continuous tunable multi-frequency;
[0052] The attenuator 32 is used to attenuate the signal light to be stored to a single-photon level.
[0053] A polarization controller 33 is configured to modulate the polarization state of the signal light to be stored into a desired polarization state, which can be represented by a Jones vector, from which the relationship between the H component and the V component of the polarization state can be clearly seen.
[0054]
[0055] More specifically, the first polarization rotator 42 is a first half-wave plate.
[0056] In the implementation, the first half-wave plate is configured to convert the vertical polarization component of the signal light to be stored into a horizontal polarization component, which is absorbed and stored by the second rare-earth doped crystal 43, and convert the horizontal polarization component released after the storage of the first rare-earth doped crystal 41 into a vertical polarization component, which is transmitted through the second rare-earth doped crystal 43 without loss. At this time, the polarization state of the photon released after the storage can be represented as:
[0057]
[0058] More specifically, the second polarization rotator 44 is a second half-wave plate.
[0059] More specifically, the angle between the fast axis of the second half-wave plate and the x-axis is 45°.
[0060] In the implementation, the second half-wave plate is configured to convert the photon released after the storage of the first rare-earth doped crystal 41 and the second rare-earth doped crystal 43 into the original polarization state.
[0061] The Jones matrix of the second half-wave plate can be represented as
[0062]
[0063] After passing through the second half-wave plate, the photon released after the storage recovers to the original polarization state:
[0064]
[0065] In the embodiment, the quantum storage module 4 based on the rare-earth doped crystal utilizes the principle of photon echo. The photon echo is generated due to the inhomogeneous broadening of the rare-earth doped crystal medium. Specifically, when a photon is incident on a two-level atomic ensemble, the photon is absorbed by the atomic ensemble. If all atoms are in phase at a certain moment, due to the coherence, the atomic ensemble re-emits the absorbed photon, achieving the process of quantum storage and emission.
[0066] More specifically, the quantum storage module 4 further includes a phase plate 45.
[0067] The output end of the second rare earth doped crystal 43 is connected with the input end of the phase plate 45, the output end of the phase plate 45 is connected with the input end of the second polarization rotator 44.
[0068] In the specific implementation, the phase plate 45 compensates the slight phase difference of the horizontal polarization state and the vertical polarization state of the photons passing through the first rare earth doped crystal 41 and the second rare earth doped crystal 43.
[0069] More specifically, the quantum storage module 4 further comprises a polarization analyzer 46;
[0070] The output end of the second polarization rotator 44 is connected with the input end of the polarization analyzer 46.
[0071] In the specific implementation, the polarization analyzer 46 detects and analyzes the polarization state of the photons after storage and release.
[0072] In the specific implementation, a light absorption box 47 is further included for absorbing the light beam.
[0073] According to the disclosure and teaching of the above description, the person skilled in the art of the present application can also change and modify the above embodiments. Therefore, the present application is not limited to the specific embodiments disclosed and described above, and some modifications and changes of the present application should fall within the protection scope of the claims of the present application. In addition, although some specific terms are used in the specification, these terms are only for convenience and do not constitute any limitation on the present application.
Claims
1. A solid state quantum storage device, characterized by, The quantum memory device comprises a laser generation module (1), a pump light modulation module (2), a storage light modulation module (3) and a quantum storage module (4). The quantum storage module (4) comprises a first rare earth doped crystal (41), a first polarization rotator (42), a second rare earth doped crystal (43) and a second polarization rotator (44) connected in sequence. The output end of the laser generation module (1) is connected with the input end of the pump light modulation module (2) and the input end of the storage light modulation module (3) respectively, and the output end of the pump light modulation module (2) and the output end of the storage light modulation module (3) are connected with the input end of the first rare earth doped crystal (41) respectively.
2. A solid state quantum memory device according to claim 1, wherein, The device further comprises a focusing lens (5), and the output end of the pump light modulation module (2) and the output end of the storage light modulation module (3) are connected with the input end of the first rare earth doped crystal (41) through the focusing lens (5) respectively.
3. A solid state quantum memory device according to claim 2, wherein, The laser generation module (1) comprises a laser (11), a polarizer (12) and a beam splitter (13). The output end of the laser (11) is connected with the input end of the polarizer (12), the output end of the polarizer (12) is connected with the first port of the beam splitter (13), the second port of the beam splitter (13) is connected with the input end of the pump light modulation module (2), and the third port of the beam splitter (13) is connected with the input end of the storage light modulation module (3).
4. A solid state quantum memory device according to claim 3, wherein, The pump light modulation module (2) comprises a first acousto-optic modulator (21) and an intensity modulator (22). The second port of the beam splitter (13) is connected with the input end of the first acousto-optic modulator (21), the output end of the first acousto-optic modulator (21) is connected with the input end of the intensity modulator (22), and the output end of the intensity modulator (22) is connected with the input end of the first rare earth doped crystal (41) through the focusing lens (5).
5. A solid state quantum memory device as claimed in claim 3, wherein, The storage light modulation module (3) comprises a second acousto-optic modulator (31), an attenuator (32) and a polarization controller (33). The third port of the beam splitter (13) is connected with the input end of the second acousto-optic modulator (31), the output end of the second acousto-optic modulator (31) is connected with the input end of the attenuator (32), the output end of the attenuator (32) is connected with the input end of the polarization controller (33), and the output end of the polarization controller (33) is connected with the input end of the first rare earth doped crystal (41) through the focusing lens (5).
6. The solid state quantum memory device of claim 1, wherein, The quantum storage module (4) further comprises a phase plate (45). The output end of the second rare earth doped crystal (43) is connected with the input end of the phase plate (45), and the output end of the phase plate (45) is connected with the input end of the second polarization rotator (44).
7. The solid state quantum memory device of claim 1, wherein, The quantum storage module (4) further comprises a polarization analyzer (46). The output end of the second polarization rotator (44) is connected with the input end of the polarization analyzer (46).
8. The solid state quantum memory device of claim 1, wherein, The first polarization rotator (42) is a first half-wave plate.
9. The solid state quantum memory device of claim 1, wherein, The second polarization rotator (44) is a second half-wave plate.
10. A solid state quantum memory device according to claim 9, wherein, The angle between the fast axis of the second half-wave plate and the x-axis is 45°.