Optical fiber underwater acoustic-magnetic integrated detection sensor based on diamond nitrogen vacancy color center

Abstract

The invention discloses an optical fiber underwater acoustic-magnetic integrated detection sensor based on a diamond nitrogen vacancy color center, which comprises a circular bottom plate, a hole is formed in the middle of the circular bottom plate, a multimode optical fiber is inserted and fixed in the hole, and the multimode optical fiber is used for being connected with an external laser pumping module and a fluorescence receiving module. The upper surface of the inner end of the multimode optical fiber is bonded with ensemble diamond, a microwave antenna is wound on the side surface of the end of the multimode optical fiber, and the end part of the microwave antenna is inserted and fixed on the circular bottom plate and is used for being connected with an external microwave generation module; a cylindrical support fixed on the circular bottom plate is buckled on the outer side of the inner end of the multimode optical fiber, a permanent magnet is fixed on the inner wall of the cylindrical support, and the upper surface of the cylindrical support is covered with a sound-sensitive diaphragm magnetic material. According to the invention, underwater acoustic signals and magnetic signals can be dynamically detected in real time, a mapping relation between the underwater acoustic signals and a dynamic magnetic field is established, and high-sensitivity measurement of underwater target multi-physical field signals is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater acoustic field and magnetic field measurement, and particularly to an optical fiber underwater acoustic-magnetic integrated detection sensor based on diamond nitrogen-vacancy color centers. Background Art

[0002] Underwater magnetic field detection sensors and underwater acoustic field detection sensors are developing rapidly, and have very broad application prospects in the fields of national defense security, environmental detection, etc. In view of the complex marine environment, there are problems such as a high false alarm probability in single physical field measurement, low sensitivity in multi-physical field integrated detection, and signal cross-interference. The underwater acoustic-magnetic integrated sensor can effectively solve the problem of cross-sensitivity in multi-physical field integrated detection, improve the sensitivity of multi-physical field integrated detection of underwater targets, and at the same time provide technical support for underwater information confrontation capabilities. Summary of the Invention

[0003] The object of the present invention is to provide an optical fiber underwater acoustic-magnetic integrated detection sensor based on diamond nitrogen-vacancy color centers, which can detect underwater acoustic signals and magnetic signals in real time and dynamically, establish a mapping relationship between underwater acoustic signals and dynamic magnetic fields, and realize highly sensitive measurement of multi-physical field signals of underwater targets.

[0004] To achieve the above object, the present invention provides an optical fiber underwater acoustic-magnetic integrated detection sensor based on diamond nitrogen-vacancy color centers, including a circular bottom plate. A central hole is opened in the circular bottom plate and a multi-mode optical fiber is inserted and fixed therein for connection with an external laser pumping module and a fluorescence receiving module. An ensemble diamond is bonded to the upper surface of the inner end of the multi-mode optical fiber. A microwave antenna is wound around the side surface of the end of the multi-mode optical fiber. The end of the microwave antenna is inserted and fixed on the circular bottom plate for connection with an external microwave generation module. A cylindrical bracket fixed on the circular bottom plate is buckled outside the inner end of the multi-mode optical fiber. A permanent magnet is fixed on the inner wall of the cylindrical bracket, and a sound-sensitive diaphragm magnetic material covers the upper surface of the cylindrical bracket.

[0005] Preferably, two permanent magnets are provided and are oppositely installed on the side walls at the top of the cylindrical bracket.

[0006] Preferably, the outside of the cylindrical bracket is covered with a rubber protection layer fixed on the circular bottom plate.

[0007] Preferably, the input and output ends of the microwave antenna are arranged parallel to the multi-mode optical fiber.

[0008] Preferably, the manufacturing method of the detection sensor is as follows:

[0009] S1. Use UV glue to bond the ensemble diamond to the upper surface of the end of the multi-mode optical fiber, and bend a single microwave antenna to wind it around the side surface of the end of the multi-mode optical fiber;

[0010] S2. Fix the multimode optical fiber and the microwave antenna on the circular bottom plate with through holes drilled, fix a cylindrical bracket with a diameter smaller than that of the circular bottom plate on the circular bottom plate, cover the upper surface of the cylindrical bracket with a sound-sensitive diaphragm, and fix the permanent magnet on the inner wall of the cylindrical bracket;

[0011] S3. Fix a rubber protective layer on the circular bottom plate to completely cover the entire cylindrical bracket, and complete the production of the entire detection sensor.

[0012] Therefore, the beneficial effects of the present invention adopting the above-mentioned fiber optic underwater acoustic-magnetic integrated detection sensor based on diamond nitrogen-vacancy color centers are as follows:

[0013] (1) The detection sensor of the present invention can realize simultaneous acoustic and magnetic detection and can realize integrated measurement of multiple physical fields of underwater targets.

[0014] (2) The detection sensor of the present invention has the characteristics of high signal-to-noise ratio and high sensitivity in detecting acoustic and magnetic signals.

[0015] (3) The detection sensor of the present invention can realize efficient conversion of underwater acoustic signals and magnetic fields, effectively improving the detection ability of underwater acoustic signals.

[0016] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of an embodiment of the fiber optic underwater acoustic-magnetic integrated detection sensor based on diamond nitrogen-vacancy color centers of the present invention;

[0018] Figure 2 is a schematic structural diagram of a detection system constructed using the detection sensor of the present invention.

[0019] Reference Signs

[0020] 1. Sound-sensitive diaphragm magnetic material; 2. Ensemble diamond; 3. Permanent magnet; 4. Rubber protective layer; 5. Microwave antenna; 6. Multimode optical fiber; 7. Laser pumping module; 8. Fluorescence receiving module; 9. Circular bottom plate; 10. Cylindrical bracket; 11. 532 nm laser; 12. Photoelectric detector; 13. Acousto-optic modulator; 14. Mirror; 15. Filter; 16. Dichroic mirror; 17. Splitter; 18. Fiber collimator; 19. Photoelectric detector; 20. Microwave amplifier; 21. Feedback controller; 22. Microwave generator; 23. Lock-in amplifier; 24. Computer. Detailed Embodiments

[0021] The technical solution of the present invention will be further described below through the drawings and embodiments.

[0022] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention pertains. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0023] Embodiment 1

[0024] As Figure 1 shown, the present invention provides an integrated fiber optic underwater acoustic and magnetic detection sensor based on diamond nitrogen-vacancy color centers, including a circular bottom plate 9. The middle of the circular bottom plate 9 is provided with an opening and a multimode optical fiber 6 is inserted and fixed therein for connection with an external laser pumping module and a fluorescence receiving module.

[0025] On the upper surface of the inner end of the multimode optical fiber 6, an ensemble diamond 2 is adhesively bonded. A single microwave antenna 5 is wound around the side surface of the end of the multimode optical fiber 6. The input and output ends of the microwave antenna 5 are bent at a certain angle and connected to the middle winding, so that the input and output ends of the microwave antenna 5 can be arranged parallel to the multimode optical fiber 6. The end of the microwave antenna 5 is inserted and fixed on the circular bottom plate 9 for connection with an external microwave generation module.

[0026] A cylindrical bracket 10 fixed to the circular bottom plate 9 is buckled outside the inner end of the multimode optical fiber 6. A permanent magnet 3 is fixed on the inner wall of the cylindrical bracket 10. In this embodiment, two permanent magnets 3 are provided and are oppositely installed on the side walls at the top of the cylindrical bracket 10. The upper surface of the cylindrical bracket 10 is covered with a magnetoacoustic diaphragm magnetic material 1. Among them, the magnetoacoustic diaphragm magnetic material 1 adopts a magnetoacoustic thin film magnetic material composite structure, such as: an iron-cobalt (FeCo) magnetostrictive sensitive film, a Pt / Co multilayer film with perpendicular magnetic anisotropy, a TbFeCo thin film and other magnetic film structures. By replacing the magnetoacoustic diaphragm magnetic material 1 on the detection sensor, magnetic field detection with different intensity ranges and different sensitivities can be realized.

[0027] In addition, the outside of the cylindrical bracket 10 in this embodiment is also coated with a rubber protection layer 4 fixed to the circular bottom plate 9 for protecting the internal structure of the detection sensor.

[0028] The manufacturing method of the detection sensor is as follows:

[0029] S1. Use UV glue to bond the ensemble diamond 2 to the upper surface of the end of the multimode optical fiber 6, and bend the single microwave antenna 5 so that it coils around the side surface of the end of the multimode optical fiber 6.

[0030] S2. Fix the multimode optical fiber 6 and the microwave antenna 5 on the circular bottom plate 9 with through holes drilled, and fix a cylindrical bracket 10 with a diameter smaller than that of the circular bottom plate 9 on the circular bottom plate 9. Cover the upper surface of the cylindrical bracket 10 with the acoustic-sensitive membrane magnetic material 1, and fix the permanent magnet 3 on the inner wall of the cylindrical bracket 10.

[0031] S3. Fix the rubber protection layer 4 on the circular bottom plate 9 to completely cover the entire cylindrical bracket 10, and complete the manufacture of the entire detection sensor.

[0032] As Figure 2 shown, when in use, make the 532nm laser 11 emit 532nm green laser, initially adjust the laser power through the acousto-optic modulator 13, and then the green laser changes the propagation direction through the mirror 14 and the dichroic mirror 16.

[0033] Next, the laser is split into two paths by the optical splitter 17. One path of the laser is received by the photodetector 19, and the result is input to the feedback controller 21. The feedback controller 21 adjusts the output laser power by connecting to the acousto-optic modulator 13 through the control end to ensure that the laser power emitted by the laser is stable and meets the preset value. The other path of the laser passes through the fiber collimator 18 and is coupled into the multimode optical fiber 6. The optical path is transmitted along the multimode optical fiber 6 to the detection sensor. The NV color centers of the ensemble diamond 2 in the detection sensor generate red fluorescent signals carrying magnetic field and acoustic field information under the influence of laser excitation and external magnetic field strength and other factors. The red fluorescent signals return along the multimode optical fiber 6 to the fiber collimator 18 and become free space light. The red fluorescence passes through the optical splitter 17 and the dichroic mirror 16 again. Since there is still green laser in this part of the optical path, the filter 15 is set to remove the green light. Finally, the red laser is received by the photodetector 12, and the data is sent to the lock-in amplifier 23.

[0034] The microwave generator 22 generates microwave signals. The microwave amplifier 20 amplifies the power of the microwave signals and transmits them to the microwave antenna 5. And the microwave generator 22 sends the reference signal to the lock-in amplifier 23. The lock-in amplifier 23 performs demodulation work through the two received signals and sends the demodulation result to the computer 24 for display. The computer terminal 24 is also connected to the feedback controller 21 and the microwave generator 22, and the parameters of the microwave signals can be set through software.

[0035] The working principle is as follows:

[0036] The energy levels of the NV color centers in the ensemble diamond 2 consist of a ground state and an excited state, both of which are spin triplets. The ground state 3A2 is composed of ms = 0 and ms = ±1. In the ground state, the spin triplet is in a degenerate state without the action of a magnetic field, with ms = ±1 being degenerate. At room temperature, there is a zero-field splitting of D = 2.87 GHz between ms = 0 and ms = ±1, and the population transfer between the ms = 0 state and the ms = ±1 state can be achieved by applying an external microwave field. That is, a microwave signal can be generated by the microwave generator 22, and then the power of this microwave signal is amplified by the microwave amplifier 20. The microwave antenna 5 radiates the microwave signal onto the NV color centers in the ensemble diamond 2 to regulate the conversion between the two states.

[0037] Under the action of a 532 nm laser pump, the NV color centers in the ground state 3A2 spin state transition to the excited state 3E, and then decay back to the 3A2 state through two pathways. One pathway is that the spin state of the NV color centers in the excited state directly returns to the 3A2 state by emitting fluorescence. The other pathway is that the NV color centers in the excited state pass through the singlet 1A1 and 1E and return to the ground state without fluorescence generation. Therefore, the spin state and energy level spacing of the NV color centers can be obtained through the change in fluorescence intensity, thereby realizing magnetic field measurement.

[0038] A flexible acoustic-sensitive diaphragm magnetic material 1 is provided in the detection sensor. When the detection sensor is placed underwater, the underwater acoustic signal vibration causes the acoustic-sensitive diaphragm magnetic material 1 to vibrate in the same pattern. At this time, the magnitude of the magnetic field strength also changes accordingly. Since the fluorescence intensity of the NV color centers in the ensemble diamond 2 is different at different magnetic field strength magnitudes, the underwater acoustic field and magnetic field can be detected by detecting the change in the fluorescence intensity signal. The fluorescence intensity signal detected by the photodetector 19 in the fluorescence receiving module is sent to the lock-in amplifier 23 for demodulation to obtain the magnitude of the current magnetic field strength. Finally, the data is transmitted into the demodulation system in the computer 24 to further separate the acoustic-magnetic aliased signal, that is, to obtain independent acoustic field signals and magnetic field signals.

[0039] Therefore, the present invention adopts the above-mentioned fiber optic underwater acoustic-magnetic integrated detection sensor based on diamond nitrogen-vacancy color centers, which can dynamically detect underwater acoustic signals and magnetic signals in real time, establish a mapping relationship between underwater acoustic signals and dynamic magnetic fields, and realize highly sensitive measurement of multi-physical field signals of underwater targets.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An optical fiber underwater acoustic and magnetic integrated detection sensor based on diamond nitrogen vacancy color centers, characterized by: It comprises a circular bottom plate, a hole is opened in the middle of the circular bottom plate and a multimode optical fiber is plugged and fixed thereon for connecting with an external laser pumping module and a fluorescence receiving module, an ensemble diamond is bonded to the upper surface of the inner end of the multimode optical fiber, a microwave antenna is coiled on the side surface of the end of the multimode optical fiber, the end of the microwave antenna is plugged and fixed on the circular bottom plate for connecting with an external microwave generating module; a cylindrical bracket fixed on the circular bottom plate is buckled on the outer side of the inner end of the multimode optical fiber, a permanent magnet is fixed on the inner wall of the cylindrical bracket, and the upper surface of the cylindrical bracket is covered with a sound-sensitive diaphragm magnetic material.

2. The optical fiber underwater acoustic and magnetic integrated detection sensor based on diamond nitrogen vacancy color centers according to claim 1 is characterized in that: The permanent magnets are provided with two and are installed oppositely on the side walls of the top of the cylindrical support.

3. The optical fiber underwater acoustic-magnetic integrated detection sensor based on diamond nitrogen vacancy color centers according to claim 1, characterized in that: The outer side of the cylindrical bracket is covered with a rubber protective layer fixed on the circular bottom plate.

4. The optical fiber underwater acoustic-magnetic integrated detection sensor based on diamond nitrogen vacancy color centers according to claim 1, characterized in that: The input and output ends of the microwave antenna are arranged in parallel with the multimode optical fiber.

5. The optical fiber underwater acoustic and magnetic integrated detection sensor based on diamond nitrogen vacancy color centers according to claim 1, characterized in that: The manufacturing method of the detection sensor is as follows: S1, using UV glue to bond the ensemble diamond to the upper surface of the multimode optical fiber end, and bend the single microwave antenna so that it is coiled on the side surface of the end of the multimode optical fiber; S2, fixing the multimode optical fiber and the microwave antenna on the circular bottom plate with a through hole, fixing a cylindrical bracket with a diameter smaller than that of the circular bottom plate on the circular bottom plate, covering the upper surface of the cylindrical bracket with a sound-sensitive diaphragm, and fixing the permanent magnet on the inner wall of the cylindrical bracket; S3. Fixing the rubber protective layer that completely covers the entire cylindrical bracket on the circular bottom plate to complete the production of the entire detection sensor.

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