Diamond NV color center microwave detector

Abstract

This invention provides a diamond NV center microwave detector, comprising: a diamond NV center, a magnetic field generator, a laser, a radio frequency probe, and a control device; the magnetic field generator generates a first magnetic field, which induces Zeeman splitting of microwave particles in the diamond NV center; the laser emits laser light towards the diamond NV center to polarize the Zeeman-split microwave particles to the Ms = |0> energy level; the magnetic field generator also generates multiple second magnetic fields of different strengths sequentially, which induce Zeeman splitting of microwave particles polarized to the Ms = |0> energy level; the radio frequency probe detects the intensity of stimulated emission of microwave particles corresponding to the intensity of the second magnetic fields; the control device determines the Zeeman-split energy level corresponding to the intensity of the second magnetic fields when the microwave particle intensity is greater than zero as the frequency of the external microwave to be detected. This invention solves the problem of limited detection of weak microwaves in space using diamond NV centers.

Description

Technical Field

[0001] This invention relates to the field of diamond color center quantum sensing technology, and more particularly to a diamond NV color center microwave detector. Background Technology

[0002] Currently, microwave detection technology based on diamond NV (Nitrogen-Vacancy) color centers is developing steadily. However, most existing microwave detection technologies based on diamond NV color centers detect changes in fluorescence caused by the interaction between the positive energy levels of diamond NV color centers through photodetectors, thereby achieving microwave detection.

[0003] However, the aforementioned microwave detection techniques can only achieve near-field microwave measurements, which greatly limits the application of diamond NV color centers in weak microwave detection in space. Summary of the Invention

[0004] This invention provides a diamond NV center microwave detector to address the problem that existing microwave detection technologies largely limit the application of diamond NV centers in weak microwave detection in space.

[0005] In a first aspect, embodiments of the present invention provide a diamond NV color center microwave detector, comprising:

[0006] Diamond NV color center, magnetic field generator, laser, radio frequency probe and control device;

[0007] The magnetic field generator is located around the diamond NV color center and is used to generate a first magnetic field, which is used to cause the microwave particles of the diamond NV color center to undergo Zeeman splitting.

[0008] The laser is used to emit laser light toward the diamond NV color center so as to polarize the microwave particles after Zeeman splitting to the Ms=|0> energy level;

[0009] The laser remains on, and the magnetic field generator is also used to generate multiple second magnetic fields with different magnetic field strengths in succession. The second magnetic field is used to cause the microwave particles polarized to the Ms=|0> energy level to undergo Zeeman splitting. The radio frequency probe is used to detect the intensity of stimulated radiation of microwave particles corresponding to the magnetic field strength of the second magnetic field.

[0010] The control device is connected to the magnetic field generator and the radio frequency probe to obtain the magnetic field strength of the second magnetic field and the corresponding stimulated emission microwave particle strength, and to determine the Zeeman splitting energy level corresponding to the magnetic field strength of the second magnetic field when the microwave particle strength is greater than zero as the frequency of the external microwave to be detected.

[0011] In one possible implementation, the control device is specifically used to plot a coordinate graph based on the magnetic field strength of the second magnetic field and the corresponding stimulated radiation microwave particle strength, and to determine the Zeeman splitting energy level corresponding to the magnetic field strength of the second magnetic field when the microwave particle strength is greater than zero as the frequency of the external microwave to be detected.

[0012] In one possible implementation, the magnetic field strength of the second magnetic field generated by the magnetic field generator is proportional to the current flowing through the magnetic field generator.

[0013] In one possible implementation, the magnetic field strength of the second magnetic field generated by the magnetic field generator ranges from 102.5 mT to 30 T.

[0014] In one possible implementation, the magnetic field directions of the first magnetic field and the second magnetic field are the same as the crystal orientation of the diamond NV color center.

[0015] In one possible implementation, the bandwidth frequency range of the radio frequency probe is 0Hz to 1000GHz.

[0016] In one possible implementation, the wavelength range of the laser is 500 nm to 600 nm, and the power range of the laser is 10 mW to 100 W.

[0017] In one possible implementation, the concentration of the diamond NV color center ranges from 0.1 ppm to 200 ppm.

[0018] In one possible implementation, the diamond NV color center is a plate-shaped diamond, and the length, width, and height of the plate-shaped diamond are all in the range of 0.1 mm to 10 mm.

[0019] In one possible implementation, a light-shielding plate is provided between the radio frequency probe and the diamond NV color center, the light-shielding plate being used to isolate the laser from the radio frequency probe to prevent the laser from reaching the radio frequency probe.

[0020] This invention provides a microwave detector for diamond NV centers. A first magnetic field is generated by a magnetic field generator to induce Zeeman splitting of microwave particles at the diamond NV centers. A laser is emitted towards the diamond NV centers to polarize the Zeeman-split microwave particles to the Ms = |0> energy level. Multiple second magnetic fields of varying strengths are then generated sequentially by the magnetic field generator to induce Zeeman splitting of the microwave particles polarized to the Ms = |0> energy level. An radio frequency probe detects the intensity of stimulated emission of microwave particles corresponding to the strength of the second magnetic fields. Finally, a control device acquires the strength of the second magnetic fields and the corresponding intensity of stimulated emission of microwave particles, and determines the frequency of the external microwave based on the magnitude of the microwave particle intensity and the strength of the second magnetic fields.

[0021] Since the Zeeman splitting energy level corresponding to the second magnetic field is exactly equal to the frequency of the external microwave to be detected, microwave particles polarized to the Ms=|0> energy level will undergo stimulated emission. Therefore, by acquiring the magnetic field strength of the second magnetic field and the corresponding microwave particle strength through a control device, and observing the magnetic field strength of the second magnetic field when the microwave particle strength is greater than zero, the frequency of the external microwave to be detected can be determined based on the Zeeman splitting energy level corresponding to the magnetic field strength of the second magnetic field. Because the Zeeman splitting energy level is linearly correlated with the magnetic field strength of the second magnetic field, by changing the magnetic field strength of the second magnetic field until the microwave particles of the diamond NV center undergo stimulated emission, the detection of weak space microwave signals can be achieved. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or related technologies 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.

[0023] Figure 1 This is a schematic diagram of the structure of a diamond NV color center microwave detector provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the principle of a diamond NV color center microwave detector provided in an embodiment of the present invention;

[0025] Figure 3 This is a coordinate graph showing the relationship between magnetic field strength and microwave particle strength provided in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of another diamond NV color center microwave detector provided in an embodiment of the present invention. Detailed Implementation

[0027] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0029] Figure 1 A schematic diagram of the structure of the diamond NV color center microwave detector provided in an embodiment of the present invention is described in detail below:

[0030] The diamond NV color center microwave detector includes: diamond NV color center 11, magnetic field generator 12, laser 13, radio frequency probe 14, and control device 15.

[0031] The magnetic field generator 12 is located around the diamond NV color center 11 and is used to generate a first magnetic field, which is used to cause the microwave particles of the diamond NV color center 11 to undergo Zeeman splitting.

[0032] Laser 13 is used to emit laser light towards the diamond NV color center 11 to polarize the microwave particles after Zeeman splitting to the Ms=|0> energy level.

[0033] Laser 13 remains on, and magnetic field generator 12 is used to generate multiple second magnetic fields with different magnetic field strengths in succession. The second magnetic field is used to cause microwave particles polarized to the Ms=|0> energy level to undergo Zeeman splitting. Radio frequency probe 14 is used to detect the intensity of stimulated radiation of microwave particles corresponding to the magnetic field strength of the second magnetic field.

[0034] The control device 15 is connected to the magnetic field generator 12 and the radio frequency probe 14 to obtain the magnetic field strength of the second magnetic field and the corresponding intensity of stimulated radiation microwave particles, and to determine the Zeeman splitting energy level corresponding to the magnetic field strength of the second magnetic field when the microwave particle intensity is greater than zero as the frequency of the external microwave to be detected.

[0035] Diamond NV center 11 refers to a special luminescent point defect in diamond, formed by a nitrogen atom replacing a carbon atom and creating a hole nearby. Diamond NV center 11 is a highly stable room-temperature solid-state single-spin quantum system with advantages such as ease of initialization, readout, manipulation, long coherence time, and room-temperature operation, making it a highly promising quantum computing system. Diamond NV center 11 contains multiple microwave particles with various states and energy levels, and these states and energy levels are influenced by magnetic fields, lasers, and microwaves.

[0036] Without an external magnetic field, the microwave particles in the diamond NV color center 11 have one of two energy levels: Ms = |±1> and Ms = |0>. Since stimulated emission of microwave particles requires converting the Ms = |±1> energy level into two energy levels, Ms = |-1> and Ms = |+1>, and under magnetic field conditions, the microwave particles in the Ms = |±1> energy level will further split due to the Zeeman effect, a magnetic field needs to be applied outside the diamond NV color center 11 to cause the microwave particles in the Ms = |±1> energy level to undergo Zeeman splitting into the Ms = |-1> and Ms = |+1> energy levels.

[0037] Figure 2 This is a schematic diagram illustrating the principle of a diamond NV color center microwave detector according to an embodiment of the present invention. Figure 2 Thus, the first magnetic field is only used to cause the microwave particles of the diamond NV color center 11 at the Ms=|±1> energy level to be split into two energy levels, Ms=|-1> and Ms=|+1>. After the diamond NV color center is split, the magnetic field generator 12 stops generating the first magnetic field.

[0038] After applying the first magnetic field using the magnetic field generator 12, the diamond NV color center 11 is irradiated with a laser for a period of time to polarize the microwave particles of the diamond NV color center 11 to the ground state Ms=|0> energy level.

[0039] In some embodiments, the magnetic field generator 12 sequentially generates multiple second magnetic fields with different magnetic field strengths. These second magnetic fields are scanning magnetic fields with a strength range of 102.5 mT to 30 T. For example, the magnetic field generator 12 generates a second magnetic field with a strength of 104 mT. When this strength does not meet the set parameters, the magnetic field generator 12 generates another second magnetic field within the scanning range. Since the strength of the second magnetic field is proportional to the current flowing through the magnetic field generator 12, in this embodiment, linear scanning of the second magnetic field can be achieved by flowing different currents into the magnetic field generator 12.

[0040] In this embodiment, when the microwave particles of the diamond NV color center 11 are polarized to the ground state Ms=|0> energy level, the microwave particle system of the diamond NV color center 11 is in an unstable state. At this time, if the frequency of the external microwave is not equal to the Zeeman splitting energy level corresponding to the magnetic field strength of the second magnetic field, the microwave particles will not be stimulated to emit radiation. If the frequency of the external microwave is exactly equal to the Zeeman splitting energy level of the second magnetic field, the microwave particles will be stimulated to emit radiation, and the intensity of the stimulated microwave particles will be detected by the radio frequency probe 14. Therefore, when the intensity of the microwave particles detected by the radio frequency probe 14 is greater than zero, the frequency of the external microwave can be obtained simply by acquiring the Zeeman splitting energy level corresponding to the magnetic field strength of the second magnetic field at this time, thus realizing the detection of the external microwave.

[0041] In some embodiments, after acquiring the magnetic field strength of the second magnetic field and the intensity of stimulated microwave particle emission corresponding to the magnetic field strength of the second magnetic field, the control device 15 can plot a coordinate graph with the magnetic field strength of the second magnetic field as the abscissa and the intensity of stimulated microwave particle emission corresponding to the magnetic field strength of the second magnetic field as the ordinate. The Zeeman splitting energy level corresponding to the magnetic field strength of the second magnetic field when the microwave particle intensity in the coordinate graph is greater than zero is determined as the frequency of the external microwave to be detected. For example, as... Figure 3 The graph showing the relationship between magnetic field strength and microwave particle strength is derived from... Figure 3 It can be seen that when the magnetic field strength is 102.5mT, 103.5mT, 104.5mT, and 106.5mT, the microwave particle intensity is 0; when the magnetic field strength is 105.5mT, the microwave particle intensity is greater than 0. Therefore, the frequency of the external microwave at this time is the Zeeman splitting energy level corresponding to the magnetic field strength of 105.5mT.

[0042] By plotting a coordinate graph based on the magnetic field strength of the second magnetic field and the intensity of stimulated microwave particles corresponding to the magnetic field strength of the second magnetic field, the magnetic field strength corresponding to the microwave particle intensity being greater than zero can be determined more clearly, and the frequency of external microwaves can be obtained more quickly.

[0043] Because the first and second magnetic fields start and stop at different times, in some embodiments, two magnetic field generators can be used to generate the first and second magnetic fields respectively. For example, as... Figure 4 Another type of diamond NV color center microwave detector shown includes a magnetic field generator 12 comprising a first magnetic field generator 121 and a second magnetic field generator 122, wherein the first magnetic field generator 121 is used to generate a first magnetic field and the second magnetic field generator 122 is used to generate a second magnetic field.

[0044] The following specific example illustrates the working process of a diamond NV color center microwave detector:

[0045] A first magnetic field generator 121 is positioned around the diamond NV color center 11, and the generator is turned on, generating a first magnetic field. Under the influence of this first magnetic field, the microwave particles of the diamond NV color center 11 undergo Zeeman splitting, with the energy level of the microwave particles splitting from the Ms=|±1> level into two energy levels: Ms=|-1> and Ms=|+1>. Once the Zeeman splitting is complete, the magnetic field generator 121 is turned off.

[0046] Laser 13 is activated, emitting a laser beam toward the diamond NV color center. At this moment, the microwave particles after Zeeman splitting are polarized to the Ms=|0> energy level.

[0047] The second magnetic field generator 122 is activated, and it successively generates multiple second magnetic fields with different magnetic field strengths. Among them, the second magnetic field causes the microwave particles polarized to the Ms=|0> energy level to undergo Zeeman splitting.

[0048] The radio frequency probe 14 is turned on to detect the intensity of stimulated radiation microwave particles. If the intensity of microwave particles detected by the radio frequency probe 14 is 0, the second magnetic field generator 122 will continue to generate a second magnetic field with a different intensity. If the intensity of microwave particles detected by the radio frequency probe 14 is greater than 0, the magnetic field generator 122 will stop generating the second magnetic field.

[0049] The control device 15 acquires and records in real time the magnetic field strength of the second magnetic field generated by the second magnetic field generator 122, as well as the microwave particle strength detected by the radio frequency probe 14 corresponding to the magnetic field strength of each second magnetic field. It also queries the magnetic field strength of the second magnetic field corresponding to the microwave particle strength being greater than 0, and finally determines the Zeeman splitting energy level corresponding to the magnetic field strength as the frequency of the external microwave to be detected.

[0050] In some embodiments, the magnetic field directions of the first magnetic field and the second magnetic field are the same as the crystal orientation of the diamond NV color center 11.

[0051] In this embodiment, the bandwidth frequency range of the radio frequency probe 14 can be from 0Hz to 1000GHz, and the noise floor can be 1fW.

[0052] Since the laser emitted by laser 13 may affect the detection results of radio frequency probe 14, therefore, Figure 4 The schematic diagram of another type of diamond NV center microwave detector shown in some embodiments indicates that a light shield 16 can be placed between the diamond NV center 11 and the radio frequency probe 14 to prevent the laser from reaching the radio frequency probe 14 and causing inaccurate detection results from the radio frequency probe 14.

[0053] In this embodiment, the light-shielding plate 16 can be made of non-metallic materials such as plastic, ceramic, or wood. It should be noted that the light-shielding plate 16 only blocks laser light and does not block stimulated emission microwave particles. Therefore, setting the light-shielding plate 16 will not affect the intensity of microwave particles detected by the radio frequency probe 14.

[0054] The embodiments of the present invention do not limit the specific location of the laser 13, for example, as Figure 1 As shown, laser 13 can be located above diamond NV color center 11, as... Figure 4 As shown, laser 13 can also be located to the left of diamond NV color center 11.

[0055] In some embodiments, the power range of the laser emitted by the laser 13 can be from 10mW to 100W, and the wavelength range of the laser can be from 500nm to 600nm. Setting the laser power between 10mW and 100W can solve the problem of excessive temperature of the diamond NV color center 11 due to excessive laser power, and reduce the frequency shift of the microwave particles of the diamond NV color center 11.

[0056] In some embodiments, the diamond NV color center 11 can be in the shape of a sheet, and the color center concentration of the diamond NV color center 11 can range from 0.1 ppm to 200 ppm. When the diamond NV color center 11 is in the shape of a sheet, the length, width, and height of the diamond NV color center 11 are all in the range of 0.1 mm to 10 mm.

[0057] As examples, the fabrication processes of two specific diamond NV color center microwave detectors are given below:

[0058] Example 1:

[0059] Step 1: Select a sheet-shaped diamond NV color center 11 with a color center concentration of 10ppm and a length, width and height of 2mm.

[0060] Step 2: Select magnetic field generator 12 to generate a first magnetic field with a magnetic field strength of 102.5 mT around the diamond NV color center 11 and the magnetic field direction is the same as the crystal orientation of the diamond NV color center 11.

[0061] Step 3: Select a laser 13 with a wavelength of 532nm and a power of 1W.

[0062] Step four: Use the magnetic field generator 12 from step two to generate a second magnetic field with a magnetic field intensity scanning range of 102.5mT to 1.8T and a magnetic field direction that is the same as the crystal orientation of the diamond NV color center 11.

[0063] Step 5: Select an RF probe 14 with a bandwidth frequency range of 3GHz to 60GHz to detect the intensity of microwave particles, and place a plastic light shield 16 between the RF probe 14 and the diamond NV color center 11.

[0064] Step six: Select control device 15 and connect it to radio frequency probe 14 and magnetic field generator 12 to obtain the magnetic field strength of the second magnetic field and the corresponding intensity of stimulated radiation microwave particles. The diamond NV color center microwave detector is now complete.

[0065] Example 2:

[0066] Step 1: Select a sheet-shaped diamond NV color center 11 with a color center concentration of 100ppm, a length and width of 10mm, and a height of 1mm.

[0067] Step 2: Select the first magnetic field generator 121 to generate a first magnetic field with a magnetic field strength of 102.5mT around the diamond NV color center 11, and the magnetic field direction is the same as the crystal orientation of the diamond NV color center 11.

[0068] Step 3: Select a laser 13 with a wavelength of 532nm and a power of 3W.

[0069] Step 4: Select the second magnetic field generator 122 to generate a second magnetic field with a magnetic field intensity scanning range of 102.5mT to 2.7T and a magnetic field direction that is the same as the crystal orientation of the diamond NV color center 11.

[0070] Step 5: Select an RF probe 14 with a bandwidth frequency range of 300MHz to 90GHz to detect the intensity of microwave particles, and place a ceramic light shield 16 between the RF probe 14 and the diamond NV color center 11.

[0071] Step six: Select control device 15 and connect it to radio frequency probe 14 and magnetic field generator 12 to obtain the magnetic field strength of the second magnetic field and the corresponding intensity of stimulated radiation microwave particles. The diamond NV color center microwave detector is now complete.

[0072] Experiments show that the microwave detector in this embodiment of the invention can achieve a detection effect of e. 15 This level of measurement enables ultra-wideband microwave detection in the DC to THz frequency band. Therefore, the diamond NV center microwave detector proposed in this embodiment of the invention utilizes the principle of stimulated emission for weak space microwave detection. This not only achieves an extremely low microwave detection limit but also features a simple detector structure, facilitating integration with other devices in the future.

[0073] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such 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, and should all be included within the protection scope of the present invention.

Claims

1. A diamond NV color center microwave detector, characterized in that, include: Diamond NV color center, magnetic field generator, laser, radio frequency probe and control device; The magnetic field generator is located around the diamond NV color center and is used to generate a first magnetic field, which is used to cause the microwave particles of the diamond NV color center to undergo Zeeman splitting. The laser is used to emit laser light toward the diamond NV color center so as to polarize the microwave particles after Zeeman splitting to the Ms=|0> energy level; The laser remains on, and the magnetic field generator is also used to generate multiple second magnetic fields with different magnetic field strengths in succession. The second magnetic field is used to cause the microwave particles polarized to the Ms=|0> energy level to undergo Zeeman splitting. The radio frequency probe is used to detect the intensity of stimulated radiation of microwave particles corresponding to the magnetic field strength of the second magnetic field. The control device is connected to the magnetic field generator and the radio frequency probe to obtain the magnetic field strength of the second magnetic field and the corresponding stimulated emission microwave particle strength, and to determine the Zeeman splitting energy level corresponding to the magnetic field strength of the second magnetic field when the microwave particle strength is greater than zero as the frequency of the external microwave to be detected.

2. The diamond NV color center microwave detector according to claim 1, characterized in that, The control device is specifically used to draw a coordinate graph based on the magnetic field strength of the second magnetic field and the corresponding intensity of stimulated radiation microwave particles, and to determine the Zeeman splitting energy level corresponding to the magnetic field strength of the second magnetic field when the microwave particle intensity is greater than zero as the frequency of the external microwave to be detected.

3. The diamond NV color center microwave detector according to claim 1, characterized in that, The magnetic field strength of the second magnetic field generated by the magnetic field generator is proportional to the current flowing through the magnetic field generator.

4. The diamond NV color center microwave detector according to claim 1, characterized in that, The magnetic field directions of the first magnetic field and the second magnetic field are the same as the crystal orientation of the diamond NV color center.

5. The diamond NV color center microwave detector according to claim 1, characterized in that, The bandwidth frequency range of the radio frequency probe is 0Hz to 1000GHz.

6. The diamond NV color center microwave detector according to claim 1, characterized in that, The wavelength range of the laser is 500nm to 600nm, and the power range of the laser is 10mW to 100W.

7. The diamond NV color center microwave detector according to claim 1, characterized in that, The concentration range of the diamond NV color centers is 0.1 ppm to 200 ppm.

8. The diamond NV color center microwave detector according to any one of claims 1-7, characterized in that, The diamond NV color center is a plate-shaped diamond, and the length, width and height of the plate-shaped diamond are all in the range of 0.1mm to 10mm.

9. The diamond NV color center microwave detector according to any one of claims 1-7, characterized in that, A light-shielding plate is provided between the radio frequency probe and the diamond NV color center. The light-shielding plate is used to isolate the laser and the radio frequency probe to prevent the laser from reaching the radio frequency probe.

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