Apparatus and method for generating non-interacting single photon source based on barnett effect

Abstract

The application discloses a device and method for generating non-reciprocal single-photon source based on Barnett effect, which comprises a core coupling unit and a multifunctional driving and regulating module, the core coupling unit is composed of a microwave cavity and a magnon embedded in the cavity core of the microwave cavity, and the multifunctional driving and regulating module comprises a mechanical rotation driving module, a magnon driving module, an optical parametric amplification module, a microwave cavity regulating module and a photon detection and output module. The application realizes spontaneous magnetization of a magnetic substrate without an external field by using the Barnett effect, does not need to additionally configure an external magnetic field, greatly reduces the size of the device, has a simple structure, is easy to realize miniaturization and multi-module integration design, and can be applied to quantum chips and other miniature quantum devices, and each module is independently regulated. The magnetization intensity is regulated through mechanical rotation, there is no external electromagnetic interference, the magnetization state is stable, the high purity, high isotropy and high emission efficiency of single photons are ensured, and the stability of the non-reciprocal emission characteristics is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of quantum optics and quantum information device technology, specifically to a device and method for generating non-reciprocal single-photon sources based on the Barnett effect. Background Technology

[0002] A single-photon source is a quantum light source that can precisely emit a single photon each time, and it is a core device for quantum communication, optical quantum computing, and precision measurement. In quantum information processing, the non-reciprocal emission property of a single-photon source (i.e., photons are emitted or transmitted only in a specific direction) is key to achieving directional transmission of quantum signals, anti-interference, and quantum logic gate operation.

[0003] Currently, the closest existing scheme to achieve the non-reciprocal property of a single-photon source typically relies on an externally strong magnetic field to modulate the magneto-optical crystal. The core structure of this scheme includes a quantum dot single-photon emission unit, a magneto-optical crystal modulation unit, an external magnetic field generation unit (such as an electromagnet), and a photon collection and coupling unit. Its working principle is to apply a directional magnetic field to the magneto-optical crystal through the external magnetic field generation unit, causing the crystal to produce a magneto-optical non-reciprocal effect, thereby modulating the direction of passing single photons.

[0004] However, the aforementioned prior art has the following significant drawbacks:

[0005] 1. Reliance on external field control and high system complexity: It requires an additional external magnetic field generating unit, resulting in a large device size and complex structure, which makes it impossible to achieve miniaturization and integration design, thus limiting its application in micro-devices such as quantum chips.

[0006] 2. Poor stability and interference with photon emission efficiency: Fluctuations in the intensity and uneven spatial distribution of the external magnetic field can cause changes in non-reciprocal properties, and the external magnetic field can generate electromagnetic interference on the quantum dot single-photon emission unit, reducing photon purity and emission efficiency.

[0007] 3. Low magneto-optical coupling efficiency and limited non-reciprocal control effect: The coupling between the external magnetic field and the magneto-optical crystal only acts on the photon transmission stage and is not directly coupled with the single-photon emission process, resulting in slow control response speed and low precision.

[0008] 4. High energy consumption and poor ease of operation: The external magnetic field generating unit requires continuous power supply, resulting in high energy consumption. Furthermore, magnetic field adjustment requires complex control circuits, making operation cumbersome. Summary of the Invention

[0009] The purpose of this invention is to provide a device and method for generating non-reciprocal single-photon sources based on the Barnett effect, which can effectively solve the problems existing in the background art.

[0010] A single-photon source device based on the Barnett effect to generate non-reciprocal photons includes a core coupling unit and a multifunctional drive and control module. The core coupling unit consists of a microwave cavity and a magnon embedded in the core of the microwave cavity. The multifunctional drive and control module includes a microwave cavity control module, an optical parametric amplification module, a mechanical rotation drive module, a magnon drive module, and a photon detection and output module.

[0011] The microwave cavity is a closed high-Q resonant cavity structure or a whispering-gallery mode structure.

[0012] The magnetic resonator is a YIG (yttrium iron garnet) magnetic sphere with a diameter of 0.3~0.5 mm;

[0013] Furthermore, the microwave cavity control module is connected to the microwave cavity and is used to tune the resonant frequency, coupling strength and cavity loss parameters of the microwave cavity in real time, match the eigenfrequency of the magnon, optimize the coupling conditions of the magnon-microwave cavity, and construct a resonant environment for single photon generation.

[0014] Furthermore, the optical parametric amplification module is optically coupled to the microwave cavity input port to excite microwave photons to a high-energy state;

[0015] Furthermore, the magnon driving module (including two external driving fields in different directions) serves two purposes. First, it excites the magnon to oscillate at a certain frequency, causing it to interact with photons via magnetic dipoles. By adjusting the magnitude of the external bias magnetic field, the magnon frequency can be modulated. Second, under the influence of the driving field, the magnon is pumped to an excited state, achieving precise preparation of the magnon's excited state.

[0016] Furthermore, the mechanical rotation drive module includes a high-precision stepper motor, a rotating shaft, and a speed control circuit; the rotating shaft is coaxially connected to the magnetic resonator, and the speed control circuit can adjust the rotational angular velocity of the stepper motor to 0~10^4 r / min;

[0017] Furthermore, the mechanical rotation drive module is coaxially connected to the magnetic resonator and is used to drive the magnetic resonator to rotate around the central axis to trigger the Barnett effect, so that the magnetic resonator is spontaneously magnetized along the rotation axis, which is used to directionally filter the emitted photons under the Barnett effect to realize the non-reciprocal emission of single photons;

[0018] Furthermore, the photon detection and output module includes an FP cavity, a collimating lens, a 50:50 beam splitter connected in sequence by optical paths, and two detectors, detector one and detector two, respectively connected to the output end of the 50:50 beam splitter. Detector one and detector two are both electrically connected to a time stamp. The time stamp is connected to a coincidence counting unit for single-photon state verification (second-order correlation function anti-beaming characteristic detection) of the microwave cavity output photons and realizing directional coupling output of single photons.

[0019] A method for generating non-reciprocal single photons using the above-described apparatus includes the following steps:

[0020] Step 1: Initial parameter matching of the system. The resonant frequency, cavity mode volume, coupling strength and loss rate of the microwave cavity are tuned by the microwave cavity control module to make its resonant frequency match the eigenfrequency of the magnon. The magnon is excited to oscillate at a certain frequency by the magnon drive module. The external static magnetic field is adjusted to make it interact with the photon with a magnetic dipole, thus constructing a coupled quantum system of magnon-microwave cavity.

[0021] Step 2: Under the external field control of the magnon drive module, the magnon is pumped to a high-energy state. By means of the coupling between the magnon and the microwave photon, the spin excitation energy is converted into single-photon energy in the microwave cavity, completing the deterministic conversion from the magnon quantum state to the photon quantum state, ensuring that the photon is in a single quantum excited state.

[0022] Step 3: In the optical parametric amplification module, the light is coupled to the microwave cavity input port, and the microwave photon is excited to a high-energy state. Based on the transition channel induced by this excitation and the transition channel under the control of the external field of the magnon, a dual quantum channel is formed and destructive interference occurs; thereby suppressing the population of the two-photon state and the two-magneton state, realizing the anti-gathering quantum property of single photon;

[0023] Step 4: Activate the mechanical rotation drive module to cause the magnon sample to rotate at high speed. The Barnett effect of the magnon occurs, converting the angular momentum of the mechanical rotation into the spin angular momentum of the magnon sample, resulting in spontaneous magnetization and shifting the magnon's intrinsic frequency. The magnitude of the frequency shift can be controlled by adjusting the rotation angular rate. Furthermore, by changing the rotation direction, the frequency shift can be reversed from positive to negative, thereby enabling directional selection of emitted single photons and achieving a non-reciprocal single-photon source.

[0024] Step 5: The photon detection and output module acquires the optical signal output from the microwave cavity, detects the second-order correlation function g²(τ) through a single-photon detector, verifies the anti-snagging characteristics to confirm the single-photon state, and realizes the directional, low-loss output of the single photon by coupling the output optical path, thus completing the preparation and output of the single-photon source.

[0025] Furthermore, as an optional implementation, the material of the magnetic resonator can be replaced with... Multiferroic materials or Antiferromagnetic material; the microwave cavity can be replaced with a Fabry-Perot microcavity or a microring resonator; the mechanical rotation drive module can be replaced with a piezoelectric ceramic driven high-frequency rotational vibration device.

[0026] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects:

[0027] 1. No external field control required, simplified device structure: This invention utilizes the Barnett effect to achieve spontaneous magnetization of the magnetic substrate without an external field. No additional external magnetic field generating unit is required, the device size is greatly reduced, the structure is simple, and it is easy to achieve miniaturization and integration design. It can be applied to micro quantum devices such as quantum chips.

[0028] 2. High system stability and excellent photon emission performance: The magnetization intensity is controlled by mechanical rotation, without external electromagnetic interference, and the magnetization state is stable, ensuring the high purity, high indistinguishability and high emission efficiency of single photons, and significantly improving the stability of non-reciprocal emission characteristics.

[0029] 3. High magneto-optical coupling efficiency and high non-reciprocal control precision: The magnetization process of the Barnett effect is directly coupled with the single-photon emission process. The magnon acts as an efficient intermediary between spin and photon, which improves the magneto-optical coupling efficiency and the response speed of non-reciprocal control. By adjusting the rotational angular velocity, the magnetization intensity can be continuously controlled, thereby achieving precise control of the non-reciprocal single-photon emission direction and efficiency.

[0030] 4. Low energy consumption and easy operation: The mechanical rotation drive module consumes far less energy than the traditional external magnetic field generating unit, and the speed control circuit is easy to operate, enabling one-button adjustment of magnetization intensity, which greatly improves the ease of operation of the device and reduces the cost of engineering applications.

[0031] 5. Integrated design with strong practicality and scalability: The functional modules are tightly coupled, resulting in low photon transmission loss. Furthermore, the non-reciprocal characteristics can be adjusted over a wide range by changing the rotational angular velocity, making it highly adaptable to various environments. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A schematic diagram of a single-photon source device for generating non-reciprocal single photons based on the Barnett effect, provided for an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the optical path connection of the photon detection and output module in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram illustrating the generation of non-reciprocal single photons in a microwave cavity-magneton coupling system based on the Barnett effect in an embodiment of the present invention. Detailed Implementation

[0036] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0037] Example 1:

[0038] like Figure 1 and Figure 2 As shown, this embodiment provides a single-photon source device based on the Barnett effect to generate non-reciprocal photons. It is an integrated structure that includes, from the core to the periphery, a microwave cavity and a magnet embedded in the microwave cavity core, a microwave cavity control module, an optical parametric amplification module, a mechanical rotation drive module, a magnet drive module, and a photon detection and output module.

[0039] The microwave cavity is a closed high-Q resonant cavity structure or a whispering-gallery mode structure;

[0040] The magnetic resonator uses YIG yttrium iron garnet magnetic spheres, with a preferred diameter of 0.3~0.5 mm.

[0041] The microwave cavity control module is connected to the microwave cavity and is used to tune the resonant frequency, coupling strength and cavity loss parameters of the microwave cavity in real time, match the eigenfrequency of the magnon, optimize the coupling conditions of the magnon-microwave cavity, and construct the resonant environment for single photon generation.

[0042] An optical parametric amplifier module, optically coupled to the microwave cavity input port, is used to excite microwave photons to a high-energy state;

[0043] The magnon driving module (comprising two external driving fields in different directions) serves two purposes. First, it excites the magnon to oscillate at a specific frequency, causing it to interact with photons via magnetic dipoles. By adjusting the magnitude of the external bias magnetic field, the magnon frequency can be modulated. Second, under the influence of the driving field, the magnon is pumped into an excited state, achieving precise preparation of the magnon's excited state.

[0044] The mechanical rotation drive module includes a high-precision stepper motor, a rotating shaft, and a speed control circuit; the rotating shaft is coaxially connected to the magnetic resonator, and the speed control circuit can adjust the rotational angular velocity of the stepper motor from 0 to 10^4 r / min;

[0045] The mechanical rotation drive module is coaxially connected to the magnet and is used to drive the magnet to rotate around the central axis to trigger the Barnett effect, so that the magnet will generate spontaneous magnetization along the rotation axis. This is used to directionally filter the emitted photons under the Barnett effect to achieve non-reciprocal emission of single photons.

[0046] The photon detection and output module includes a photonic cavity (FP cavity), a collimating lens, a 50:50 beam splitter, detector one, detector two, a time stamp, and a coincidence counting unit. After being output from the FP cavity, a single photon passes through the collimating lens and is incident on the 50:50 beam splitter. The split beam then enters detector one and detector two respectively. The electrical signals from both detectors are transmitted to the time stamp, and finally, the coincidence counting unit processes the data for single-photon state verification (second-order correlation function anti-focusing characteristic detection) of the microwave cavity output photon, and to achieve directional coupling output of the single photon.

[0047] Example 2:

[0048] Step 1: Initial parameter matching of the system. The resonant frequency, cavity mode volume, coupling strength and loss rate of the microwave cavity are tuned by the microwave cavity control module to make its resonant frequency match the eigenfrequency of the magnon. The magnon is excited to oscillate at a certain frequency by the magnon drive module. The external static magnetic field is adjusted to make it interact with the photon with a magnetic dipole, thus constructing a coupled quantum system of magnon-microwave cavity.

[0049] Step 2: Under the external field control of the magnon drive module, the magnon is pumped to a high-energy state. By means of the coupling between the magnon and the microwave photon, the spin excitation energy is converted into single-photon energy in the microwave cavity, completing the deterministic conversion from the magnon quantum state to the photon quantum state, ensuring that the photon is in a single quantum excited state.

[0050] Step 3: In the optical parametric amplification module, the light is coupled to the microwave cavity input port, and the microwave photon is excited to a high-energy state. Based on the transition channel induced by this excitation and the transition channel under the control of the external field of the magnon, a dual quantum channel is formed and destructive interference occurs; thereby suppressing the population of the two-photon state and the two-magneton state, realizing the anti-gathering quantum property of single photon;

[0051] Step 4: Activate the mechanical rotation drive module to cause the magnon sample to rotate at high speed. The Barnett effect of the magnon occurs, converting the angular momentum of the mechanical rotation into the spin angular momentum of the magnon sample, resulting in spontaneous magnetization and shifting the magnon's intrinsic frequency. The magnitude of the frequency shift can be controlled by adjusting the rotation angular rate. Furthermore, by changing the rotation direction, the frequency shift can be reversed from positive to negative, thereby enabling directional selection of emitted single photons and achieving a non-reciprocal single-photon source.

[0052] Step 5: The photon detection and output module acquires the optical signal output from the microwave cavity, detects the second-order correlation function g²(τ) through a single-photon detector, verifies the anti-snagging characteristics to confirm the single-photon state, and realizes the directional, low-loss output of the single photon by coupling the output optical path, thus completing the preparation and output of the single-photon source.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for generating non-reciprocal single-photon sources based on the Barnett effect, characterized in that... It includes a core coupling unit and a multi-functional drive and control module. The core coupling unit consists of a microwave cavity and a magnet embedded in the core of the microwave cavity. The multi-functional drive and control module includes a microwave cavity control module, an optical parametric amplification module, a mechanical rotation drive module, a magnet drive module, and a photon detection and output module. The microwave cavity is a closed high-Q resonant cavity structure or a whispering-gallery mode structure. The magnetic resonator is a YIG (yttrium iron garnet) magnetic sphere with a diameter of 0.3~0.5 mm.

2. The device for generating a non-reciprocal single-photon source based on the Barnett effect according to claim 1, characterized in that... The microwave cavity control module is connected to the microwave cavity and is used to tune the resonant frequency, coupling strength and cavity loss parameters of the microwave cavity in real time, match the eigenfrequency of the magnon, optimize the coupling conditions between the magnon and the microwave cavity, and construct a resonant environment for single-photon generation.

3. The device for generating a non-reciprocal single-photon source based on the Barnett effect according to claim 1, characterized in that... The optical parametric amplification module is optically coupled to the microwave cavity input port to excite microwave photons to a high-energy state.

4. The device for generating a non-reciprocal single-photon source based on the Barnett effect according to claim 1, characterized in that... The magnet drive module is used to excite the magnet to oscillate at a certain frequency, so that it interacts with the photon via a magnetic dipole. The magnitude of the external bias magnetic field can be adjusted, and the frequency of the magnet can be modulated.

5. A single-photon source device for generating non-reciprocal single photons based on the Barnett effect according to claim 1, characterized in that... The magnetic resonator driving module can pump the magnetic resonator to an excited state under the action of a driving field, thereby achieving precise preparation of the excited state of the magnetic resonator.

6. The device for generating a non-reciprocal single-photon source based on the Barnett effect according to claim 1, characterized in that... The mechanical rotation drive module includes a high-precision stepper motor, a rotating shaft, and a speed control circuit; the rotating shaft is coaxially connected to the magnetic resonator, and the speed control circuit can adjust the rotational angular velocity of the stepper motor to 0~10^4 r / min.

7. The mechanical rotation drive module is coaxially connected to the magnetic resonator and is used to drive the magnetic resonator to rotate around the central axis to trigger the Barnett effect, so that the magnetic resonator is spontaneously magnetized along the rotation axis, which is used to directionally filter the emitted photons under the Barnett effect to realize the non-reciprocal emission of single photons.

8. A single-photon source device for generating non-reciprocal single photons based on the Barnett effect according to claim 1, characterized in that... The photon detection and output module includes an FP cavity, a collimating lens, a 50:50 beam splitter connected in sequence by optical paths, and two detectors, detector one and detector two, respectively connected to the output end of the 50:50 beam splitter. Detector one and detector two are both electrically connected to a time stamp. The time stamp is connected to a coincidence counting unit for single-photon state verification (second-order correlation function anti-focusing characteristic detection) of the microwave cavity output photons and realizing directional coupling output of single photons.

9. A method for generating non-reciprocal single photons using a single-photon source device, characterized in that... Includes the following steps: Step 1: Initial parameter matching of the system. The resonant frequency, cavity mode volume, coupling strength and loss rate of the microwave cavity are tuned by the microwave cavity control module to make its resonant frequency match the eigenfrequency of the magnon. The magnon is excited to oscillate at a certain frequency by the magnon drive module. The external static magnetic field is adjusted to make it interact with the photon with a magnetic dipole, thus constructing a coupled quantum system of magnon-microwave cavity. Step 2: Under the external field control of the magnon drive module, the magnon is pumped to a high-energy state. By means of the coupling between the magnon and the microwave photon, the spin excitation energy is converted into single-photon energy in the microwave cavity, completing the deterministic conversion from the magnon quantum state to the photon quantum state, ensuring that the photon is in a single quantum excited state. Step 3: In the optical parametric amplification module, the light is coupled to the microwave cavity input port, and the microwave photon is excited to a high-energy state. Based on the transition channel induced by this excitation and the transition channel under the control of the external field of the magnon, a dual quantum channel is formed and destructive interference occurs; thereby suppressing the population of the two-photon state and the two-magneton state, realizing the anti-gathering quantum property of single photon; Step 4: Activate the mechanical rotation drive module to cause the magnet sample to rotate at high speed. The Barnett effect of the magnet sample occurs, converting the angular momentum of the mechanical rotation into the spin angular momentum of the magnet sample, resulting in spontaneous magnetization. This causes the intrinsic frequency of the magnet to shift. By adjusting the rotation angular rate, the magnitude of the frequency shift can be controlled. In addition, by changing the rotation direction, the frequency shift of the magnet can be converted from positive to negative, thereby enabling directional screening of the emitted single photons and realizing a non-reciprocal single photon source. Step 5: The photon detection and output module acquires the optical signal output from the microwave cavity, detects the second-order correlation function g²(τ) through a single-photon detector, verifies the anti-snagging characteristics to confirm the single-photon state, and realizes the directional, low-loss output of the single photon by coupling the output optical path, thus completing the preparation and output of the single-photon source.

10. A method for generating non-reciprocal single photons using a single-photon source device according to claim 1, characterized in that... The material of the magnet can be replaced with... Multiferroic materials or Antiferromagnetic material; the microwave cavity can be replaced with a Fabry-Perot microcavity or a microring resonator; the mechanical rotation drive module can be replaced with a piezoelectric ceramic driven high-frequency rotational vibration device.

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