Microwave coupled optical detection magnetic resonance apparatus

Abstract

The application discloses a microwave coupling light detection magnetic resonance device, and aims at the problems of NV color center quantum state in diamond, such as difficult initialization, operation and reading, and light intensity change detection. The optical system connecting unit of the microwave coupling light detection magnetic resonance device comprises an imaging laser, an excitation laser, a collimation adapter, an optical path chamber, a lens assembly and a camera. The optical path chamber is internally provided with a reflecting mirror group, a two-phase color mirror, a middle reflecting mirror and a first half-transmission half-reflection mirror. Laser emitted by a laser emitter is reflected by the reflecting mirror group multiple times and enters the lens assembly, is split by the first half-transmission half-reflection mirror into one light path entering an optical spectrum analyzer and another light path entering a counting unit. The counting unit is provided with a single-photon detector and a half-transmission half-reflection mirror. A microwave signal is applied to a sample. The microwave coupling light detection magnetic resonance device is designed in a multi-channel optical path mode, realizes simultaneous measurement of spectrum, light intensity and light image, and has the functions of light-microwave pulse modulation and quantum light source anti-bunching.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor materials and quantum technology, specifically relating to an NV color center optical-magnetic control device in diamond. Background Technology

[0002] The quantum system of color centers within diamond (NV centers) is unaffected by the external environment due to the strong carbon-carbon bonds. Compared to commonly used quantum systems, such as cold atom systems, ion traps, and Josephson junctions, which require ultra-low temperatures or high vacuum environments to minimize noise levels, diamond color centers exhibit excellent quantum coherence properties at room temperature and ambient pressure. This has broad potential applications in quantum information processing, quantum computing, and the rapidly developing field of quantum detection. The unique feature of diamond NV centers is that their electron spin Hamiltonians contain parameters of magnetic, electric, stress, and temperature fields, making their spin states sensitive to external stimuli and suitable for use as sub-nanometer-scale ultra-weak field quantum detection devices. Another characteristic is that different spin states of NV centers exhibit different fluorescence intensities, which will establish a connection between microscopic quantum states and macroscopic optical fields. Summary of the Invention

[0003] This invention addresses the problems of difficulty in initializing, manipulating, and reading out the quantum states of NV color centers in diamond, as well as the detection of changes in the light intensity of NV color centers, by providing a microwave coupled optical detection magnetic resonance (ODMR) device.

[0004] The microwave coupled optical detection magnetic resonance (ODMR) device of the present invention includes an optical system connection unit, a microwave system connection unit, a spectrometer and a counting unit. The optical system connection unit includes an imaging laser, an excitation laser, a collimation adapter, an optical path chamber, a lens assembly and a camera. The collimation adapter is connected to the imaging laser via an optical fiber. An acousto-optic modulator is provided between the excitation laser and the optical path chamber.

[0005] The optical path chamber contains a mirror assembly, a dichroic mirror, a middle mirror, and a first semi-transparent mirror. The laser emitted by the laser emitter is reflected multiple times by the mirror assembly and enters the lens assembly. The lens assembly consists of an upper component, a middle component, and a lower component. The optical path chamber is located behind the upper component, and the collimation adapter is located behind the lower component. The upper component has a built-in lens mirror that reflects the laser from the optical path chamber vertically downward and is focused by the objective lens onto the diamond sample with the NV color center. The middle component has a built-in lens semi-transparent mirror with a pull rod. A camera is connected to the side of the middle component via the optical path. The lower component has a built-in mirror with a pull rod.

[0006] The diamond sample with the NV color center is located directly below the lens assembly;

[0007] The signal light from the diamond sample with NV color center is changed from vertical (upward) to parallel light by the lens assembly and reflected into the optical path chamber. The signal light then passes through the dichroic mirror and the middle mirror in sequence and is then split by the No. 1 semi-transparent and semi-reflective mirror. The No. 1 semi-transparent and semi-reflective mirror is equipped with a pull rod.

[0008] One beam of light is dispersed through the first semi-transparent and semi-reflective mirror and enters the spectrometer, while the other beam enters the counting unit. The counting unit contains two single-photon detectors and the second semi-transparent and semi-reflective mirror.

[0009] The microwave system connection unit includes a microwave radio frequency source, which applies microwave signals to the diamond sample with NV color centers.

[0010] This invention relates to a microwave-coupled optical detection magnetic resonance (ODMR) device. By designing a coupling optical acquisition unit, a microwave radio frequency unit, and an electrical control unit, it constructs an ODMR device to achieve optical polarization, microwave manipulation, and state readout of the NV color center quantum state. The system features a multi-channel optical path mode, enabling simultaneous measurement of spectrum, light intensity, and optical image, and possesses a series of functions such as optical-microwave pulse modulation and quantum light source anti-focusing. Based on this device, not only can a novel set of quantum detection modes for physical parameters be established, breaking through the classical measurement limit and approaching or reaching the Heisenberg limit, but it can also realize the manipulation of three quantum qubits, developing a new technological roadmap for quantum computing.

[0011] This microwave-coupled optical detection magnetic resonance device is designed and built as a complete platform for the characterization, detection, manipulation, and application of NV centers in solid-state quantum systems in the field of quantum technology. It provides technical support for key engineering fields such as diamond-based NV center quantum sensors and single-photon sources, and has significant demonstrative and guiding effects. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the microwave-coupled optical detection magnetic resonance device of the present invention;

[0013] Figure 2 This is a schematic diagram of the internal structure of the optical path chamber, with the arrows indicating the optical path reflection paths.

[0014] Figure 3 This is a schematic diagram of the lens assembly.

[0015] Figure 4 Diagram showing the positional relationship between the lens assembly and the optical path chamber;

[0016] Figure 5 This is a photograph of the interior of the optical path chamber in the embodiment;

[0017] Figure 6 This is a photograph of the actual optical path module for the counting part in the embodiment;

[0018] Figure 7 In this embodiment, a microwave-coupled optical detection magnetic resonance device is used to obtain an optical image test pattern;

[0019] Figure 8 In this embodiment, a microwave-coupled optical detection magnetic resonance device is used to obtain the spectral test pattern;

[0020] Figure 9 The example uses a microwave-coupled light probe magnetic resonance device to obtain a test diagram of fluorescence intensity response to magnetic field and microwave, with the values ​​along the arrow direction being -15dB, -10dB, -5dB, and 0dB respectively. Detailed Implementation

[0021] Specific Implementation Method 1: The microwave coupled optical detection magnetic resonance device in this implementation method includes an optical system connection unit, a microwave system connection unit, a spectrometer A23, and a counting unit A3. The optical system connection unit includes an imaging laser A11, an excitation laser A21, a collimation adapter A12, an optical path chamber 2, a lens assembly 3, and a camera 4. The collimation adapter A12 is connected to the imaging laser A11 via an optical fiber. An acousto-optic modulator 7 is provided between the excitation laser A21 and the optical path chamber 2.

[0022] The optical path chamber 2 contains a mirror group 2-1, a dichroic mirror 2-2, a middle mirror 2-3, and a first semi-transparent mirror 2-4. The laser emitted by the laser emitter A21 is reflected multiple times by the mirror group 2-1 and enters the lens assembly 3. The lens assembly 3 consists of an upper component, a middle component, and a lower component. The optical path chamber 2 is located at the rear of the upper component, and the collimation adapter A12 is located at the rear of the lower component. The upper component contains a lens mirror 3-1, which allows the laser from the optical path chamber 2 to be reflected and focused vertically downwards by the objective lens onto the diamond sample 6 with the NV color center. The middle component contains a lens semi-transparent mirror 3-2, which has a pull rod. The middle component is connected to the side of the optical path via an optical path to a camera 4. The lower component contains a mirror 3-3 with a pull rod.

[0023] Diamond sample 6 with NV color center is located directly below lens assembly 3;

[0024] The signal light from the diamond sample 6 with the NV color center is reflected from vertical (upward) to parallel light by the lens assembly 3-1 and enters the light path chamber 2. The signal light then passes through the dichroic mirror 2-2 and the central reflector 2-3 in sequence and is then split by the first semi-transparent and semi-reflective mirror 2-4. The first semi-transparent and semi-reflective mirror 2-4 is equipped with a pull rod.

[0025] One beam of light enters the spectrometer A23 through the first semi-transparent and semi-reflective mirror 2-4, and the other beam enters the counting unit A3. The counting unit A3 is equipped with two single-photon detectors and the second semi-transparent and semi-reflective mirror A34.

[0026] The microwave system connection unit includes a microwave radio frequency source B2, which applies microwave signals to the diamond sample 6 with the NV color center.

[0027] Specific Implementation Method Two: The difference between this implementation method and Specific Implementation Method One is that the laser A11 uses a 532nm green laser.

[0028] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the imaging laser A11 and the excitation laser A21 are respectively connected to the power supply 1.

[0029] Specific Implementation Method Four: This implementation method differs from one of the specific implementation methods one to three in that the camera 4 is a color camera.

[0030] Specific Implementation Method 5: This implementation method differs from Specific Implementation Methods 1 to 4 in that the diamond sample 6 with the NV color center is placed on the sample stage 5.

[0031] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the second semi-transparent mirror A34 in the counting unit A3 is equipped with a pull rod. In the counting unit A3, the light is split again by the second semi-transparent mirror A34. One path of the split light enters the second single-photon detector A32, and the other path of the split light enters the first single-photon detector A31.

[0032] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that a focusing lens A35 is provided between the central reflecting mirror 2-3 and the first semi-transparent and semi-reflective mirror 2-4.

[0033] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the microwave system connection unit includes a microwave radio frequency source B2, a power amplifier C1, a microwave switch C2, and a microwave antenna C3. The radio frequency microwave signal generated by the microwave radio frequency source B2 is connected to the microwave antenna C3 through a transmission line, and the power amplifier C1 and the microwave switch C2 are arranged sequentially on the transmission line.

[0034] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method One or Eight in that the microwave coupled optical detection magnetic resonance device is also equipped with a timing generator B3, which is connected to the microwave switch C2, the acousto-optic modulator 7 and the data acquisition card A24 via control lines.

[0035] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that it acquires photon counting signals using a data acquisition card A24.

[0036] Example: The microwave coupled light detection magnetic resonance device in this example includes an optical system connection unit, a microwave system connection unit, a spectrometer A23, a counting unit A3, and a timing generator B3. The optical system connection unit includes an imaging laser A11, an excitation laser A21, a collimation adapter A12, an optical path chamber 2, a lens assembly 3, and a camera 4. The collimation adapter A12 is connected to the imaging laser A11 via an optical fiber. An acousto-optic modulator 7 is provided between the excitation laser A21 and the optical path chamber 2.

[0037] The optical path chamber 2 contains a mirror group 2-1, a dichroic mirror 2-2, a middle mirror 2-3, a focusing lens A35, and a first semi-transparent mirror 2-4. The laser emitted by the laser emitter A21 is reflected multiple times by the mirror group 2-1 and enters the lens assembly 3. The lens assembly 3 consists of an upper component, a middle component, and a lower component. The optical path chamber 2 is located at the rear of the upper component, and the collimation adapter A12 is located at the rear of the lower component. The upper component contains a lens mirror 3-1, which allows the laser from the optical path chamber 2 to be reflected and focused vertically downwards by the objective lens onto the diamond sample 6 with the NV color center. The middle component contains a lens semi-transparent mirror 3-2, which has a pull rod. The middle component is connected to the side of the optical path via an optical path to a camera 4. The lower component contains a mirror 3-3 with a pull rod.

[0038] Diamond sample 6 with NV color center is placed on sample stage 5 and located directly below lens assembly 3;

[0039] The signal light from the diamond sample 6 with the NV color center is reflected from vertical (upward) to parallel light by the lens assembly 3-1 and enters the light path chamber 2. The signal light then passes through the dichroic mirror 2-2, the central reflector 2-3 and the focusing lens A35 in sequence, and is then split by the first semi-transparent and semi-reflective mirror 2-4. The first semi-transparent and semi-reflective mirror 2-4 is equipped with a pull rod.

[0040] One beam of light enters the spectrometer A23 through the first semi-transparent and semi-reflective mirror 2-4, and the other beam enters the counting unit A3. The second semi-transparent and semi-reflective mirror A34 in the counting unit A3 has a lever. The light is split again through the second semi-transparent and semi-reflective mirror A34 in the counting unit A3. One beam enters the second single-photon detector A32, and the other beam enters the first single-photon detector A31.

[0041] The microwave system connection unit includes a microwave radio frequency source B2, a power amplifier C1, a microwave switch C2, and a microwave antenna C3. The radio frequency microwave signal generated by the microwave radio frequency source B2 is connected to the microwave antenna C3 through a transmission line. The microwave signal is applied to the diamond sample 6 with the NV color center.

[0042] The timing generator B3 is connected to the microwave switch C2, the acousto-optic modulator 7, and the data acquisition card A24 via control lines.

[0043] In this embodiment, the dichroic mirror 2-2 reflects light with a wavelength of 532nm while allowing light with higher wavelengths to pass through. The incident light enters the lens assembly 3 after being reflected by the mirror group 2-1 and the dichroic mirror 2-2; the signal light of the sample returns along the original optical path and passes through the dichroic mirror 2-2 to the central mirror 2-3.

[0044] This embodiment also includes a data acquisition and distribution unit comprising a computer B1 for receiving data and distributing control signals; a data acquisition card A24 for receiving photon counting signals; a spectrometer A23 for receiving spectral signals; and a timing generator B3 for distributing pulse timing signals.

[0045] The microwave-coupled optical detection magnetic resonance (ODMR) device in this embodiment mainly includes four units: optical system connection, data acquisition and distribution microwave system connection, and timing pulse control.

[0046] The optical system connection unit includes an imaging section, a spectral section, and a counting section. The imaging section includes a basic optical path for light propagation; a high-power 532nm green laser A11 for focusing on the sample surface, providing optical morphology information of the sample surface, and providing sufficient intensity illumination to excite the emission of individual NV centers within the diamond; a collimation adapter A12 for adjusting the laser's output light source into uniform parallel light to illuminate the sample surface; a reflector 3-3 with a lever for controlling whether the sample is in a bright field or dark field environment; a color camera 4 for observing the sample surface morphology or identifying the distribution position of individual NV centers on the diamond surface; and a semi-transparent mirror 3-2 with a lever for controlling whether the sample's reflected light signal is transmitted to the color camera. When this element is in the optical path, the sample surface signal will simultaneously enter the color camera and the spectral section to achieve a combined optical image / spectral testing function. When this element is off the optical path, the sample signal only enters the spectral section.

[0047] The spectral section includes a basic optical path for light propagation, a low-power 532nm green light exciter A21 for exciting local color centers on the surface to emit light, an acousto-optic modulator 7 for constructing pulsed lasers, a microscope lens A12 in the imaging section for focusing the laser emission source onto the sample surface, a spectrometer A23 for acquiring the sample spectral signal to achieve Raman spectral detection or photoluminescence fluorescence spectral detection, and a semi-transparent mirror 2-4 with a lever for controlling whether the sample signal enters the spectrometer. When this element is in the optical path, the sample surface signal will enter both the spectrometer and the counting section to achieve the spectral / light intensity coordinated testing function. When this element is off the optical path, the sample signal only enters the counting section. The counting section includes a basic optical path for light propagation, which shares some optical elements with the imaging and spectral sections; two single-photon detectors to detect sample light intensity signals and perform anti-focusing to determine whether the light source is a single-photon source; a filter A35 to control the wavelength range of photons entering the detector; a semi-transparent mirror A34 with a lever to control whether the sample signal enters both photon detectors simultaneously. When this element is in the optical path, the sample surface signal is split into two paths and enters the two single-photon detectors for autocorrelation testing. When this element is off the optical path, the sample signal enters only one single-photon detector for counting testing; and a data acquisition card A24 to receive single-photon detector signals and transmit them to the computer.

[0048] The microwave system connection unit includes a microwave RF source B2 for generating RF microwave signals of different frequencies and intensities; a power amplifier C1 for amplifying the amplitude of the RF microwave signals; a microwave switch C2 for controlling the on / off state of microwave signal transmission; and a microwave antenna C3 for loading the microwave signals onto the diamond NV color center.

[0049] The timing pulse control unit includes a timing generator B3, which distributes TTL signals with the same phase to microwave switch C2, data acquisition card A24, and acousto-optic modulator 7 to construct timing pulse lasers, timing pulse microwaves, and timing pulse detectors, and to obtain pulsed light detection magnetic resonance spectra, Rabi oscillation spectra, free relaxation decay, and Hahn echo measurements.

[0050] Optical image spectrum test diagram as follows Figures 7-9 As shown, this is the photo taken by the camera when the mirror 3-3 with the lever, the lens semi-transparent mirror 3-2, and the first semi-transparent mirror 2-4 are in the optical path, and the second semi-transparent mirror A34 is not in the optical path. Figure 7 ), spectral instrument acquisition signal ( Figure 8 ), the light intensity signal collected by the counter ( Figure 9 ).

[0051] The microwave-coupled optical detection magnetic resonance device in this embodiment can realize a series of experiments such as NV color center quantum state initialization, manipulation and readout, as well as NV monochromatic center distribution location, NV color center spectrum measurement, NV color center light intensity change detection, and single photon source testing.

Claims

1. A microwave coupled optical detection magnetic resonance apparatus, characterized by The microwave coupling optical detection magnetic resonance device comprises an optical system connecting unit, a microwave system connecting unit, a spectrometer (A23) and a counting unit (A3), wherein the optical system connecting unit comprises an imaging laser (A11), an excitation laser (A21), a collimation adapter (A12), an optical path chamber (2), a lens assembly (3) and a camera (4), the collimation adapter (A12) is connected with the imaging laser (A11) through an optical fiber, and an acousto-optic modulator (7) is arranged between the excitation laser (A21) and the optical path chamber (2); The inside of the optical path chamber (2) is provided with a mirror group (2-1), a two-phase color mirror (2-2), a middle mirror (2-3) and a first half-transmission half-reflection mirror (2-4), the laser emitter (A21) emits laser light which is reflected multiple times by the mirror group (2-1) into the lens assembly (3), the lens assembly (3) is composed of an upper layer part, a middle layer part and a lower layer part, the optical path chamber (2) is located at the rear of the upper layer part, and the collimation adapter (A12) is located at the rear of the lower layer part; the upper layer part is internally provided with a lens mirror (3-1) so that the laser light from the optical path chamber (2) is focused vertically downward by an objective lens on a diamond sample (6) with NV color centers after being reflected, the middle layer part is internally provided with a lens half-transmission half-reflection mirror (3-2), the lens half-transmission half-reflection mirror (3-2) is provided with a pull rod, the camera (4) is connected through an optical path at the side of the middle layer part, and the lower layer part is internally provided with a mirror (3-3) provided with a pull rod; The diamond sample (6) with NV color centers is located directly below the lens assembly (3); The signal light of the diamond sample (6) with NV color centers is reflected into the optical path chamber (2) by the lens assembly (3-1) from the vertical direction to parallel light, the signal light is then sequentially reflected by the two-phase color mirror (2-2) and the middle mirror (2-3) and is split by the first half-transmission half-reflection mirror (2-4), and the first half-transmission half-reflection mirror (2-4) is provided with a pull rod; One of the split lights passing through the first half-transmission half-reflection mirror (2-4) enters the spectrometer (A23), and the other split light enters the counting unit (A3), two single-photon detectors and a second half-transmission half-reflection mirror (A34) are arranged in the counting unit (A3); the second half-transmission half-reflection mirror (A34) in the counting unit (A3) is provided with a pull rod, the split light is split again in the counting unit (A3) through the second half-transmission half-reflection mirror (A34), one of the split lights enters the second single-photon detector (A32), and the other split light enters the first single-photon detector (A31); The microwave system connecting unit comprises a microwave radio frequency source (B2), so that the microwave signal is applied to the diamond sample (6) with NV color centers.

2. The microwave-coupled optical detection magnetic resonance device of claim 1, wherein The laser (A11) is a 532nm green laser.

3. The microwave-coupled optical detection magnetic resonance device of claim 1, wherein The imaging laser (A11) and the excitation laser (A21) are respectively connected with a power supply (1).

4. The microwave-coupled optical detection magnetic resonance device of claim 1, wherein The camera (4) is a color camera.

5. The microwave-coupled optical detection magnetic resonance device of claim 1, wherein The diamond sample (6) with NV color centers is placed on a sample table (5).

6. The microwave-coupled optical detection magnetic resonance device of claim 1, wherein A focusing lens (A35) is arranged between the middle mirror (2-3) and the first half-transmission half-reflection mirror (2-4).

7. The microwave-coupled optical detection magnetic resonance device of claim 1, wherein The microwave system connecting unit comprises a microwave radio frequency source (B2), a power amplifier (C1), a microwave switch (C2) and a microwave antenna (C3), the radio frequency microwave signal generated by the microwave radio frequency source (B2) is connected with the microwave antenna (C3) through a transmission line, and the power amplifier (C1) and the microwave switch (C2) are sequentially arranged on the transmission line.

8. The microwave-coupled optical detection magnetic resonance device of claim 1 or 7, wherein The microwave coupling light detection magnetic resonance device is also provided with a time sequence generator (B3), and the time sequence generator (B3) is connected with the microwave switch (C2), the acoustooptic modulator (7) and the data acquisition card (A24) through control lines.

9. The microwave-coupled optical detection magnetic resonance device of claim 8, wherein The photon counting signal is collected through the data acquisition card (A24).

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