Optical detection magnetic resonance detection system based on diamond NV color center

Abstract

The utility model relates to the technical field of optical detection magnetic resonance, in particular to an optical detection magnetic resonance detection system based on a diamond NV color center, which comprises a to-be-detected sample loading unit, a laser excitation and detection unit, a microwave generation and emission unit, a magnetic field unit and a system control and data acquisition processing unit, the to-be-tested sample loading unit is provided with a diamond NV color center, and the laser excitation and detection unit, the microwave generation and emission unit and the magnetic field unit are all arranged on the periphery of the to-be-tested sample loading unit; the magnetic field unit provides a proper magnetic field environment for the to-be-tested sample loading unit; the laser excitation and detection unit is matched with the magnetic field unit to excite and detect a fluorescence signal emitted by a diamond NV color center; the microwave generation and emission unit is used for adjusting the intensity of a fluorescence signal; and the system control and data acquisition processing unit communicates with the microwave generation and emission unit and receives the adjusted fluorescence signal. Through modular design of the detection system, the flexibility of the system is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of optical detection magnetic resonance, in particular to an optical detection magnetic resonance detection system based on diamond NV color centers. BACKGROUND

[0002] The NV (nitrogen vacancy) color center is a kind of defect with fluorescence signal characteristics in diamond, which is formed by a nitrogen atom replacing a carbon atom and its adjacent vacancy. The NV color center has vector sensitivity in space, and the static magnetic field along the NV axis direction and the polarization electromagnetic field perpendicular to the NV axis plane will both affect the fluorescence signal characteristics of the NV color center. The measurement of the fluorescence signal intensity is carried out through the optical detection magnetic resonance (ODMR) method, the energy level splitting caused by the Zeeman effect is known by using the fluorescence signal change and the microwave frequency, and then the change of the local magnetic field can be obtained.

[0003] The existing optical detection magnetic resonance detection system has the problems of system complexity and difficulty in adjustment and upgrading. CONTENT OF THE INVENTION

[0004] The application aims to provide an optical detection magnetic resonance detection system based on diamond NV color centers to improve the problems of system complexity and difficulty in adjustment and upgrading of the original optical detection magnetic resonance detection system.

[0005] The optical detection magnetic resonance detection system based on diamond NV color centers provided by the application adopts the following technical scheme: a to-be-detected sample loading unit, a laser excitation and detection unit, a microwave generation and emission unit, a magnetic field unit and a system control and data acquisition and processing unit are arranged, the to-be-detected sample loading unit is provided with a diamond NV color center and is used for placing a to-be-detected sample, the laser excitation and detection unit, the microwave generation and emission unit and the magnetic field unit are arranged around the to-be-detected sample loading unit; the magnetic field unit provides a suitable magnetic field environment for the to-be-detected sample loading unit; the laser excitation and detection unit cooperates with the magnetic field unit to excite the diamond NV color center to emit a fluorescence signal; the microwave generation and emission unit is used for adjusting the fluorescence signal intensity; the system control and data acquisition and processing unit communicates with the microwave generation and emission unit and receives the adjusted fluorescence signal.

[0006] Through the above technical scheme, when the to-be-detected sample passes near the diamond NV color center, the magnetic field characteristics of the to-be-detected sample molecules will disturb the magnetic field distribution near the diamond NV color center, and then affect the emission of the fluorescence signal. Through the analysis of the change of the fluorescence signal intensity, the molecular structure information of the to-be-detected sample can be obtained. Through the modular design of the detection system, the flexibility of the system is improved.

[0007] Optionally, the sample loading unit comprises a sample delivery module and a waveguide module; the waveguide module comprises a silicon substrate, a diamond film and a quartz sample cell; the diamond film with diamond NV color centers is arranged above the silicon substrate, and the quartz sample cell is arranged on the diamond film; the quartz sample cell is provided with a sample groove close to the diamond film.

[0008] By adopting the above technical scheme, the sample loading unit is simple in structure, and the sample to be measured can be conveniently replaced and supplemented.

[0009] Optionally, the laser excitation and detection unit comprises a light source module, a microscope objective, a dichroic mirror and a single-photon detector; the microscope objective, the dichroic mirror and the single-photon detector are sequentially arranged on the same side of the sample loading unit; the light source module generates laser for exciting the diamond NV color centers, and focuses the laser on the NV color centers of the diamond film in the sample area through the microscope objective to excite the generation of fluorescent signals; the dichroic mirror is used for separating the laser and the fluorescent signals; and the single-photon detector is used for receiving the separated fluorescent signals, converting the fluorescent signals into electrical signals, amplifying and filtering the electrical signals, and transmitting the electrical signals to the system control and data acquisition processing unit.

[0010] By adopting the above technical scheme, the generation and transmission of the fluorescent signals are realized.

[0011] Optionally, the microwave transmitting antenna is a microwave transmitting coil, and a center line of the microwave transmitting coil coincides with a center line of the sample area to be measured.

[0012] By adopting the above technical scheme, the effective utilization rate of the microwave can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a system block diagram of an embodiment of the utility model.

[0014] Figure 2 is a partial structure schematic view of the utility model embodiment.

[0015] In the figure, 1, sample loading unit to be measured;11, sample delivery module;12, waveguide module;121, silicon substrate;122, diamond film;123, quartz sample cell;2, laser excitation and detection unit;21, light source module;22, microscope objective;23, dichroic mirror;24, single-photon detector;3, microwave generation and transmitting unit;31, microwave generator;32, power amplifier;33, microwave switch;34, microwave transmitting antenna;4, magnetic field unit;5, system control and data acquisition processing unit. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings Figure 1 - appendixFigure 2 The application is described in further detail below.

[0017] A light detection magnetic resonance detection system based on diamond NV color centers, referring to Figure 1 The light detection magnetic resonance detection system comprises a sample loading unit 1, a laser excitation and detection unit 2, a microwave generation and emission unit 3, a magnetic field unit 4, and a system control and data acquisition processing unit 5. The sample loading unit 1 is provided with diamond NV color centers and is used for placing a sample to be measured. The magnetic field unit 4 is arranged around the sample loading unit 1 and is used for generating a fixed magnetic field environment so that the diamond NV color centers generate energy level splitting due to the Zeeman effect, and the magnetic field component parallel to the NV axis is generated.

[0018] The system control and data acquisition processing unit 5 communicates with the laser excitation and detection unit 2. The system control and data acquisition processing unit 5 controls the laser excitation and detection unit 2 to excite the diamond NV color centers and detect the fluorescence signal emitted by the diamond NV color centers, and controls the laser excitation and detection unit 2 to transmit the fluorescence signal to the system control and data acquisition processing unit 5. The system control and data acquisition processing unit 5 communicates with the microwave generation and emission unit 3. The system control and data acquisition processing unit 5 controls the microwave generation and emission unit 3 to generate microwaves and transmit the microwaves into the sample loading unit 1, so as to realize the change of the influence on the fluorescence signal intensity.

[0019] The laser excitation and detection unit 2 and the microwave generation and emission unit 3 are arranged around the sample loading unit 1. When the sample to be measured passes near the diamond NV color centers, the magnetic field characteristics of the sample to be measured will disturb the magnetic field distribution near the diamond NV color centers, and then affect the emission of the fluorescence signal. Therefore, through the analysis of the change of the fluorescence signal intensity, the molecular structure information of the sample to be measured can be obtained.

[0020] Specifically, referring to Figure 2 The sample loading unit 1 comprises a sample conveying module 11 and a waveguide module 12. The sample conveying module 11 is used for loading the sample to be measured into the sample area of the waveguide module 12. The waveguide module 12 serves as a detection area of the sample to be measured and cooperates with the laser excitation and detection unit 2 and the control microwave generation and emission unit 3 to realize the excitation and enhancement of the fluorescence signal.

[0021] The waveguide module 12 comprises a silicon substrate 121, a diamond film 122, and a quartz sample cell 123. The diamond film 122 with diamond NV centers is arranged above the silicon substrate 121. The quartz sample cell 123 is arranged on the diamond film 122 by optical cementing. The quartz sample cell 123 is provided with a sample groove close to the diamond film 122. In the embodiment, the sample is a liquid. The sample delivery module 11 comprises a micro-fluidic pump and a delivery pipeline. The micro-fluidic pump can deliver the liquid sample to the sample groove of the diamond film 122 for subsequent detection.

[0022] Specifically, the laser excitation and detection unit 2 comprises a light source module 21, a microscope objective 22, a dichroic mirror 23, and a single-photon detector 24. The microscope objective 22, the dichroic mirror 23, and the single-photon detector 24 are sequentially arranged on the same side of the sample loading unit 1. The light source module 21 generates laser light of a specific wavelength that can efficiently excite the NV centers of the diamond film 122. The laser light is focused by the microscope objective 22 onto the diamond NV centers in the sample area of the diamond film 122. The generated fluorescence signal is collected by the microscope objective 22. Based on the principle of a confocal microscope, the collection efficiency and spatial resolution of the fluorescence signal are improved. The fluorescence signal is collected by the microscope objective 22 and guided to the subsequent dichroic mirror 23. The dichroic mirror 23 is used to separate the laser light and the fluorescence signal. The laser light is reflected by the dichroic mirror 23 back to the laser source direction. The fluorescence signal is detected by the single-photon detector 24 after passing through the dichroic mirror 23. The single-photon detector 24 converts the received fluorescence signal into an electrical signal and performs amplification and filtering processing for the system control and data acquisition processing unit 5 to analyze and extract information about the magnetic resonance characteristics of the sample.

[0023] The light source module 21 can be a continuous wave (CW) laser or a pulsed laser, depending on the experimental requirements and the characteristics of the color centers. The selection of the microscope objective 22 depends on the distribution of color centers in the sample area and the required focusing accuracy. The microscope objective 22 has a high numerical aperture (NA) to ensure that the laser light can effectively excite the fluorescence signal. The single-photon detector 24 includes an avalanche photodiode (APD), a silicon photomultiplier (SiPM), etc. Similarly, the dichroic mirror 23 can also be selected to reflect the fluorescence signal and transmit the laser light. The relative positions of the light source module 21, the microscope objective 22, the dichroic mirror 23, and the single-photon detector 24 are adjusted accordingly.

[0024] Specifically, the microwave generation and emission unit 3 comprises a microwave generator 31, a power amplifier 32, a microwave switch 33 and a microwave emission antenna 34; wherein the microwave generator 31 generates microwave resonance signals of a specific frequency, the microwave resonance signals are amplified by the power amplifier 32, and then the microwave emission antenna 34 is controlled by the microwave switch 33 to emit the microwave resonance signals, so as to realize the change of the influence on the fluorescence signal intensity. In the embodiment of the present application, the microwave emission antenna 34 is set as a microwave emission coil, which is preferably arranged on the silicon substrate 121, and the center line of the microwave emission coil coincides with the center line of the sample to-be-detected region, so as to improve the microwave utilization rate.

[0025] In the embodiment of the present application, the magnetic field unit 4 is composed of a permanent magnet, which is arranged around the sample to-be-detected loading unit 1 to provide a uniform and constant magnetic field distribution. Similarly, a coil type magnet can also be used, and a fluxgate detector is used for real-time monitoring.

[0026] The implementation principle of the embodiment of the present application is as follows: under the action of the magnetic field generated by the permanent magnet, the diamond NV color center of the diamond thin film 122 generates energy level splitting due to the Zeeman effect; after the specific wavelength laser generated by the light source module 21 acts on the diamond NV color center, the carriers are excited from the ground state to the high-energy state, and the spin state in the high-energy state occurs non-radiative transition, and then returns to the ground state through the radiation of different wavelength fluorescence signals, so as to realize the generation of fluorescence signals, and then the microwave signal generated by the microwave generator 31 reaches the resonance condition to realize the adjustment of the fluorescence signal.

[0027] When the sample to-be-detected passes through the quartz sample cell 123, due to the magnetic field characteristics of the sample to-be-detected molecules, the magnetic field distribution near the NV color center of the diamond thin film 122 is disturbed, and then the emission of the fluorescence signal is affected. By analyzing the change of the fluorescence signal intensity, the molecular structure information of the sample to-be-detected can be obtained.

[0028] The optical detection nuclear magnetic resonance detection system is designed by modularization, and the sample to-be-detected loading unit 1, the laser excitation and detection unit 2 and the microwave generation and emission unit 3 can be adjusted accordingly according to the actual change of the sample to-be-detected, so that the system is easy to upgrade and the flexibility of the system is improved.

[0029] The embodiments of the specific implementation mode are the preferred embodiments of the present application, but do not limit the protection scope of the present application, wherein the same parts are indicated by the same reference numerals. Therefore: any equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A diamond NV color center based optical detection magnetic resonance detection system, characterized by: It includes a sample loading unit (1), a laser excitation and detection unit (2), a microwave generation and emission unit (3), a magnetic field unit (4) and a system control and data acquisition processing unit (5), the sample loading unit (1) is provided with diamond NV color centers, and is used for containing the sample to be tested, the laser excitation and detection unit (2), the microwave generation and emission unit (3) and the magnetic field unit (4) are all arranged around the sample loading unit (1); the magnetic field unit (4) provides a suitable magnetic field environment for the sample loading unit (1); the laser excitation and detection unit (2) cooperates with the magnetic field unit (4) to excite and detect the fluorescence signal emitted by the diamond NV color center; the microwave generation and emission unit (3) is used for adjusting the fluorescence signal intensity; the system control and data acquisition processing unit (5) communicates with the microwave generation and emission unit (3) to receive the adjusted fluorescence signal.

2. The diamond NV color center based optical detection magnetic resonance detection system according to claim 1, wherein: The sample loading unit (1) includes a sample delivery module (11) and a waveguide module (12); the waveguide module (12) includes a silicon substrate (121), a diamond thin film (122) and a quartz sample cell (123); the diamond thin film (122) has diamond NV color centers, which is arranged above the silicon substrate (121), and the quartz sample cell (123) is arranged on the diamond thin film, and the quartz sample cell (123) is provided with a sample groove close to the diamond thin film.

3. The diamond NV color center based optical detection magnetic resonance detection system according to claim 2, wherein: The laser excitation and detection unit (2) includes a light source module (21), a microscope objective (22), a dichroic mirror (23) and a single photon detector (24); the microscope objective (22), the dichroic mirror (23) and the single photon detector (24) are sequentially arranged on the same side of the sample loading unit (1); the light source module (21) generates laser for exciting diamond NV color centers, which is focused on the diamond NV color centers of the diamond thin film (122) through the microscope objective (22) to excite fluorescence signals, and the dichroic mirror (23) is used for separating the laser and the fluorescence signals; the single photon detector (24) is used for receiving the separated fluorescence signals and converting the fluorescence signals into electrical signals, and the electrical signals are amplified and filtered, and then transmitted to the system control and data acquisition processing unit (5).

4. The diamond NV-color center based optical detection magnetic resonance detection system according to claim 3, wherein: The microwave generation and emission unit (3) includes a microwave generator (31), a power amplifier (32), a microwave switch (33) and a microwave emission antenna (34); the microwave generator (31) generates a microwave resonance signal, the power amplifier (32) is used for amplifying the microwave resonance signal, and the microwave switch (33) controls the microwave emission antenna (34) to emit the microwave resonance signal.

5. The diamond NV-color center based optical detection magnetic resonance detection system according to claim 4, wherein: The microwave emission antenna (34) is arranged as a microwave emission coil, and the center line of the microwave emission coil coincides with the center line of the sample testing area.

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