Diamond NV color center-based temperature and magnetic field measurement method, device and chip

Abstract

The invention provides a temperature and magnetic field measurement method and device based on a diamond NV color center and a chip. The method comprises the steps that a sample to be measured is placed on a sample table with diamond; emitting laser to the sample table to excite the NV color center of the diamond; the microwave system adopts a modulation mode with the frequency of f1 to emit modulation microwaves to the sample to be tested; the sCMOS camera collects a first fluorescence image emitted by the diamond at the frequency f2; meanwhile, turning on a switching power supply of the sample to be detected, performing temperature modulation, performing frequency phase-locked modulation on the on-off state of the switching power supply in combination with the frequency of the microwave system, and acquiring a second fluorescence image emitted by the diamond by the sCMOS camera; demodulating the obtained first fluorescence image and the second fluorescence image as a period to obtain the temperature variable of the sample to be detected, and the sensitivity and the detection speed of chip temperature measurement can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of NV color center temperature measurement, in particular to a temperature and magnetic field measurement method, device and chip based on diamond NV color center. BACKGROUND

[0002] NV color center is a point defect formed by nitrogen atom replacing carbon atom and accompanied by adjacent vacancy in diamond, and its structure has C 3v symmetry, and the energy levels of the ground state (3A2) and the excited state (3E) of electron spin are significantly affected by temperature. The zero-field splitting value D of the ground state energy level is 2.87 GHz, which will move linearly with the increase of temperature. This phenomenon can be accurately captured by the optical detection magnetic resonance (ODMR) technology, and becomes the physical basis of temperature sensing. In addition, the electron spin state of the NV color center can be initialized to the m s =0 energy level by 532 nm laser, and the spin state reading can be realized by the difference of fluorescence intensity, which makes it have stable quantum state control ability at room temperature.

[0003] With the improvement of chip integration to nanoscale, thermal management has become a key challenge. Traditional temperature measurement technologies such as thermocouple (contact type) have problems such as insufficient spatial resolution (millimeter level), interference with the measured object. Although the infrared thermal imager realizes non-contact measurement, it is limited by the diffraction limit (micron resolution) and the material emissivity dependence. The hot spot size of high-density chips has been reduced to sub-micron scale, and dynamic thermal gradient may cause local failure or performance fluctuations, so nanoscale, non-destructive real-time temperature monitoring means are needed.

[0004] NV color center becomes an ideal solution for chip temperature measurement due to the following characteristics:

[0005] 1. High sensitivity and wide dynamic range: Through ODMR spectral line shift detection, the temperature sensitivity can reach the order of mK / √Hz, which is suitable for extreme environments from-269℃ to +700℃.

[0006] 2. Non-invasive and compatibility: The diamond probe can directly contact the chip surface without introducing electromagnetic interference, and is compatible with scanning microscope technology, supporting three-dimensional temperature field imaging.

[0007] 3. Multi-physical quantity cooperative measurement: The same NV color center can simultaneously perceive temperature, magnetic field and stress, providing multi-dimensional data for chip fault diagnosis.

[0008] Currently, NV center temperature measurement technology has been used in the following scenarios: 1. Pre-packaging chip thermal verification, scanning the surface of the die through a nanodiamond probe array, identifying thermal leakage points caused by process defects 2. Dynamic thermal management optimization, real-time monitoring of nanoscale hot spots during CPU / GPU runtime, guiding heat dissipation structure design and optimizing power distribution. 3. Quantum chip characterization, in-situ measurement of local temperature rise near superconducting quantum bits, reducing decoherence effects.

[0009] In summary, NV color center temperature measurement technology breaks through the classical physical limit through quantum effects, providing a revolutionary tool for thermal reliability research of post-moore era chips. Its combination with artificial intelligence algorithms, such as deep learning assisted temperature field modeling, will further promote the innovation of chip design paradigm.

[0010] In the chip detection field, although the temperature measurement technology based on diamond NV color centers has shown the potential of high-precision quantum sensors, it still faces the challenges of insufficient sensitivity and slow detection speed. First, the temperature detection of NV color centers relies on the response of its spin state to external temperature changes, but in existing methods, the phonon thermal effect of the diamond substrate when excited by laser and the band excitation effect caused by paramagnetic impurities will reduce the contrast of the fluorescence signal, directly affecting the sensitivity of temperature measurement. For example, in the traditional continuous pulse light detection magnetic resonance technology, the band excitation will introduce additional noise, reducing the signal-to-noise ratio and limiting the ability to capture weak temperature changes. Second, the temperature response speed of NV color centers is limited by the efficiency of spin polarization and fluorescence reading. Although the contrast can be partially improved by optimizing pulse shaping techniques (such as Gaussian pulses), the complex microwave control and signal processing procedures still prolong the detection period, making it difficult to meet the real-time requirements of chip detection scenarios (such as fast dynamic temperature rise monitoring). In addition, current technology focuses more on magnetic detection optimization, and systematic research on temperature measurement is relatively less. For example, the insufficient thermal coupling efficiency between diamond NV color centers and the chip surface, and the imperfect environmental temperature drift compensation mechanism further restrict the sensitivity and response speed of its actual application.

[0011] The invention patent with patent application publication number CN118671669A discloses a diamond NV color center quantum sensing frequency following method based on digital-analog control. In the process of obtaining the resonance frequency signal of the diamond NV color center to control the microwave frequency of the microwave source, the PID control method is adopted to reduce errors such as optical noise and electromagnetic interference. However, this patent is a method for detecting magnetic field using diamond NV color centers. SUMMARY

[0012] The technical problem to be solved by the present application is the insufficient sensitivity and slow detection speed of temperature measurement technology based on diamond NV color centers.

[0013] To solve the above technical problems, the present application provides the following technical solutions:

[0014] A temperature and magnetic field measurement method based on diamond NV color centers, comprising:

[0015] Placing a sample to be measured on a sample stage with a diamond;

[0016] Emitting laser to the sample stage to excite the NV color centers of the diamond;

[0017] The microwave system adopts a modulation mode with a frequency f1 and emits modulated microwaves towards the sample to be measured;

[0018] The sCMOS camera adopts a frequency f2 to collect a first fluorescent image emitted by the diamond; at the same time, a switch power supply of the sample to be measured is turned on for temperature modulation, and the on-off state of the switch power supply is combined with the frequency of the microwave system for frequency phase-locked modulation, and the sCMOS camera collects a second fluorescent image emitted by the diamond;

[0019] The first fluorescent image and the second fluorescent image obtained are demodulated as a cycle to obtain the temperature variable of the sample to be measured.

[0020] In this embodiment, the sCMOS camera is applied to demodulate the first fluorescent image obtained to obtain the magnetic field variable or the temperature variable of the sample to be measured.

[0021] In this embodiment, the collection timing of the sCMOS camera is synchronized with the modulation timing of the microwave system.

[0022] In this embodiment, the frequency f2 is twice the frequency f1.

[0023] In this embodiment, the first fluorescent image is four equal fluorescent cumulative images, and the optical signals in the first fluorescent image can be in-phase differential measurement and quadrature differential measurement.

[0024] In this embodiment, the sCMOS camera adopts the frequency f2 to collect the second fluorescent image.

[0025] In this embodiment, the second fluorescent image is four equal fluorescent cumulative images, and the optical signals in the second fluorescent image can be in-phase differential measurement and quadrature differential measurement.

[0026] In this embodiment, when the magnetic field and temperature variable of the sample to be measured are obtained, the optical signals corresponding to the first fluorescent image and the second fluorescent image in N cycles are averaged and then demodulated.

[0027] In this embodiment, the sCMOS camera is internally integrated with a phase-locked amplifier.

[0028] The application also provides a diamond NV color center-based temperature and magnetic field measuring device, which applies the diamond NV color center-based temperature and magnetic field measuring method.

[0029] A sample table with a diamond, used for carrying a sample to be measured;

[0030] A laser module, used for emitting laser to the sample table to excite the NV color center of the diamond;

[0031] A microwave module, used for emitting modulated microwaves to the sample to be measured in a modulation mode of the microwave system with a frequency f1;

[0032] An sCMOS camera, used for collecting a first fluorescent image emitted by the diamond with a frequency f2;

[0033] A control terminal, used for opening a switching power supply of the sample to be measured, performing temperature modulation, and performing frequency-locked phase modulation of the on-off state of the switching power supply in combination with the frequency of the microwave system while the sCMOS camera collects the first fluorescent image;

[0034] And the sCMOS camera collects a second fluorescent image emitted by the diamond; and demodulates the first fluorescent image and the second fluorescent image as a cycle to obtain the temperature variable of the sample to be measured.

[0035] The application also provides a chip for measuring by applying the diamond NV color center-based temperature and magnetic field measuring method.

[0036] Compared with the prior art, the application has the beneficial effects that the chip is measured once when the switch is opened and closed, the sCMOS camera performs temperature and magnetic field modulation at the same time in each measurement, real-time temperature distribution information is obtained through temperature decoupling, the temperature field is modulated through the chip switch, low-frequency noise interference is excluded through phase-locked demodulation, and the temperature measurement technical sensitivity is improved. When the sCMOS camera demodulates, only the quadrature and in-phase images are demodulated, the entire frequency spectrum is not scanned through the frequency point phase-locked manner, and the detection efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 A diamond NV color center-based temperature and magnetic field measuring method flowchart of an embodiment of the application.

[0038] Figure 2 A diamond NV color center-based temperature and magnetic field measuring system schematic diagram of an embodiment of the application.

[0039] Figure 3 A phase-locked temperature decoupling test sequence diagram of an embodiment of the application.

[0040] Figure 4This is a schematic diagram of temperature and magnetic field decoupling in an embodiment of the present invention. Detailed Implementation

[0041] To facilitate understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will now be further described in conjunction with the accompanying drawings.

[0042] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0043] Example 1

[0044] Please see Figure 1 , Figure 2 As shown, this invention provides a method for measuring temperature and magnetic field based on diamond NV centers, including:

[0045] S10, place the sample to be tested on a sample stage with diamond.

[0046] In this embodiment, the sample to be tested is a chip.

[0047] S20 emits a laser beam toward the sample stage to excite the NV color centers of diamond.

[0048] In this embodiment, a 532nm green laser is used to excite the NV color centers. Furthermore, the 532nm green laser remains on throughout the entire measurement process.

[0049] S30, the microwave system uses a modulation mode with frequency f1 to emit modulated microwaves toward the sample under test.

[0050] In this embodiment, the microwave field applied to the sample by the microwave system is modulated using a modulation mode with frequency f1 to drive the spin state transition of the NV color center.

[0051] The modulated microwaves emitted by the microwave system can be generated using an arbitrary waveform generator.

[0052] The S40 sCMOS camera uses a frequency of f2 to acquire the first fluorescence image emitted by the diamond. Simultaneously, the power supply of the sample under test is turned on to perform temperature modulation. The on / off state of the power supply is combined with the frequency of the microwave system for frequency lock-in modulation, and the sCMOS camera acquires the second fluorescence image emitted by the diamond.

[0053] In this embodiment, the sCMOS camera controls the internal frame acquisition timing via an external trigger pulse. The sampling frequency f2 is twice the frequency f1, synchronized with the microwave modulation; that is, the acquisition timing of the sCMOS camera is synchronized with the modulation timing of the microwave system. The sCMOS camera uses frequency f2 to acquire the first fluorescence image emitted by the diamond. At this time, the first fluorescence image is a cumulative fluorescence image of four equally divided segments, and as shown... Figure 3 As shown, the power supply to the sample under test is off, meaning the sample is in a non-operating state. Specifically, the first fluorescence images include First Fluorescence Image 1 (S1), First Fluorescence Image 2 (S2), First Fluorescence Image 3 (S3), and First Fluorescence Image 4 (S4). The light signals in First Fluorescence Image 1 and First Fluorescence Image 3 can be measured using in-phase differential measurement, and the light signals in First Fluorescence Image 2 and First Fluorescence Image 4 can be measured using orthogonal differential measurement. This can be understood as the four equally divided cumulative fluorescence images allowing for in-phase differential (S1-S3) and orthogonal differential (S2-S4) measurements of the light signals. The first fluorescence images include magnetic field and temperature information; when using an sCMOS camera for demodulation, the magnetic field and temperature quantities can be demodulated as needed.

[0054] In this embodiment, temperature modulation is simultaneously achieved through a switching power supply, combined with frequency phase-locked modulation, such as... Figure 3 As shown, when the switching power supply is turned on, the chip operates and generates heat. Therefore, the second fluorescence image acquired by the sCMOS camera at frequency f2 at this time contains both magnetic field information and chip temperature change information. Undoubtedly, the second fluorescence image is also a cumulative fluorescence image of four equally divided segments, allowing for in-phase differential and quadrature differential measurements of the optical signal.

[0055] S50 demodulates the first fluorescence image and the second fluorescence image as a cycle to obtain the temperature variable of the sample to be tested.

[0056] In this embodiment, temperature modulation is performed using a switching power supply, combined with frequency lock-in modulation, to obtain a pair of in-phase images and a pair of quadrature images in the on and off states, respectively. The sCMOS camera integrates a lock-in amplifier, and demodulation is performed through the sCMOS camera to obtain the magnetic field and temperature variables of the sample under test, such as... Figure 4 As shown. More specifically, when acquiring the magnetic field and temperature of the sample to be tested, the light signals corresponding to the first fluorescence image and the second fluorescence image under N periods are averaged and then demodulated. Figure 4 middle, f is the center frequency at the initial temperature. T The center frequency under temperature changes.

[0057] Please see Figures 1 to 4As shown in the embodiment, to address the chip temperature detection requirements, a chip temperature modulation technique combined with dual-channel frequency differential decoupling temperature measurement, along with an sCMOS camera, was developed to achieve fast, highly sensitive, high-resolution, and wide-field-of-view temperature imaging. For the temperature and magnetic field decoupling measurement method, a magnetic field signal is simultaneously generated when the chip is in its hot-operation state and the current is turned on. Through the aforementioned temperature-microwave decoupling measurement, the magnetic field and temperature quantities can be obtained separately, thereby achieving fast and highly sensitive imaging of multiple physical quantities.

[0058] Example 2

[0059] Please see Figure 2 As shown, the present invention also provides a temperature and magnetic field measuring device based on diamond NV centers, which applies the above-described temperature and magnetic field measuring method based on diamond NV centers, including:

[0060] A diamond-encrusted sample stage is used to hold the sample to be tested.

[0061] The laser module is used to emit laser light onto the sample stage to excite the NV color centers of diamond.

[0062] A microwave module is used in a microwave system to emit modulated microwaves toward the sample under test using a modulation mode at frequency f1.

[0063] An sCMOS camera is used to capture the first fluorescence image emitted by diamond at a frequency of f2.

[0064] The control terminal is used to turn on the switching power supply of the sample under test while the sCMOS camera acquires the first fluorescence image, to perform temperature modulation, and to perform frequency lock-in modulation by combining the on and off states of the switching power supply with the frequency of the microwave system.

[0065] Additionally, an sCMOS camera acquires a second fluorescence image emitted by the diamond; and the acquired first fluorescence image and second fluorescence image are demodulated as a cycle to obtain the temperature variable of the sample under test.

[0066] Example 3

[0067] Please see Figures 1 to 4 As shown, the present invention also provides a chip that uses the temperature and magnetic field measurement method based on diamond NV color centers described above for measurement.

[0068] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0069] The above embodiments are merely examples of implementation methods of the invention. The scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A method of measuring temperature and magnetic field based on diamond NV color centers, characterized in that, The method comprises the following steps: placing a sample to be measured on a sample stage with a diamond; emitting laser to the sample stage to excite NV centers of the diamond; a microwave system adopts a modulation mode with a frequency f1 to emit modulated microwaves towards the sample to be measured; an sCMOS camera adopts a frequency f2 to collect a first fluorescent image emitted by the diamond; at the same time, a switching power supply of the sample to be measured is turned on for temperature modulation, and the on-off state of the switching power supply is combined with the frequency of the microwave system for frequency phase-locked modulation, and the sCMOS camera collects a second fluorescent image emitted by the diamond; the first fluorescent image and the second fluorescent image obtained are demodulated as a cycle to obtain a temperature variable of the sample to be measured. 2.The diamond NV color center based temperature and magnetic field measurement method according to claim 1, wherein, The collection timing of the sCMOS camera is synchronized with the modulation timing of the microwave system. 3.The diamond NV color center based temperature and magnetic field measurement method according to claim 1, wherein, The frequency f2 is twice the frequency f1. 4.The diamond NV color center based temperature and magnetic field measurement method according to claim 3, wherein, The first fluorescent image is four equal-division fluorescent cumulative images, and the light signals in the first fluorescent image can be in-phase differential measurement and quadrature differential measurement. 5.The diamond NV color center based temperature and magnetic field measurement method according to claim 3, wherein, The second fluorescent image is four equal-division fluorescent cumulative images, and the light signals in the second fluorescent image can be in-phase differential measurement and quadrature differential measurement. 6.The diamond NV color center based temperature and magnetic field measurement method of claim 1, wherein, When the magnetic field and temperature variables of the sample to be measured are obtained, the light signals corresponding to the first fluorescent image and the second fluorescent image in N cycles are averaged and then demodulated. 7.The diamond NV color center based temperature and magnetic field measurement method of claim 1, wherein, The sCMOS camera is used to demodulate the first fluorescent image to obtain the magnetic field variable or the temperature variable of the sample to be measured. 8.The diamond NV color center based temperature and magnetic field measurement method of claim 1, wherein, The sCMOS camera is internally integrated with a phase-locked amplifier.

9. A diamond NV center based temperature, magnetic field measurement device, characterized by, The method for measuring temperature and magnetic field based on diamond NV centers according to any one of claims 1-8 comprises: a sample stage with a diamond for carrying a sample to be measured; a laser module for emitting laser to the sample stage to excite NV centers of the diamond; a microwave module for a microwave system to adopt a modulation mode with a frequency f1 to emit modulated microwaves towards the sample to be measured; an sCMOS camera for adopting a frequency f2 to collect a first fluorescent image emitted by the diamond; a control terminal for turning on a switching power supply of the sample to be measured at the same time when the sCMOS camera collects the first fluorescent image, for temperature modulation, and for combining the on-off state of the switching power supply with the frequency of the microwave system for frequency phase-locked modulation; and the sCMOS camera collects a second fluorescent image emitted by the diamond; and the first fluorescent image and the second fluorescent image obtained are demodulated as a cycle to obtain a temperature variable of the sample to be measured.

10. A chip, characterized by The method for measuring temperature and magnetic field based on diamond NV centers according to any one of claims 1-8 is used for measurement.

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