CN117805703A - NV color center magnetic sensor and temperature drift compensation method thereof - Google Patents

NV color center magnetic sensor and temperature drift compensation method thereof Download PDF

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Publication number
CN117805703A
CN117805703A CN202311871409.6A CN202311871409A CN117805703A CN 117805703 A CN117805703 A CN 117805703A CN 202311871409 A CN202311871409 A CN 202311871409A CN 117805703 A CN117805703 A CN 117805703A
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signal
microwave signal
microwave
temperature drift
color center
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孙峰
许克标
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Guoyi Quantum Technology Hefei Co ltd
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Guoyi Quantum Technology Hefei Co ltd
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Abstract

The embodiment of the invention discloses an NV color center magnetic sensor and a temperature drift compensation method thereof, wherein the magnetic sensor comprises a laser current source, a probe module and a microwave module, wherein the laser current source is used for providing driving current for the probe module so as to enable the probe module to generate laser signals; the microwave module is used for providing a composite microwave signal for the probe module, and the NV color center is used for generating a fluorescent signal according to the laser signal and the composite microwave signal; the composite microwave signal is formed by superposing a first microwave signal and a second microwave signal, and the frequencies and phases of the first microwave signal and the second microwave signal are different, so that the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value. According to the scheme, the temperature drift signal amplitude of the NV color center under the first microwave signal and at least part of the temperature drift signal amplitude of the NV color center under the second microwave signal can be offset, so that the temperature drift coefficient of the NV color center magnetic sensor is reduced, and the measuring precision of the NV color center sensor is improved.

Description

NV color center magnetic sensor and temperature drift compensation method thereof
Technical Field
The embodiment of the invention relates to the technical field of magnetic measurement, in particular to an NV color center magnetic sensor and a temperature drift compensation method thereof.
Background
The NV (Nitrogen-vacuum) color center is a point defect structure in diamond, has stable optical property, can detect the fluorescent signal change of the NV color center through a light detection magnetic resonance technology to judge the current magnetic resonance state of the NV color center, and then calculates the magnetic induction intensity according to the current microwave frequency, thereby realizing the magnetic measurement function.
However, the magnetic measurement result of the NV color center magnetic sensor is susceptible to temperature, thereby reducing the magnetic measurement accuracy.
Disclosure of Invention
The embodiment of the invention provides an NV color center magnetic sensor and a temperature drift compensation method thereof, which are used for improving the temperature drift of an NV color center so as to reduce the influence of temperature change on the magnetic measurement precision of the NV color center magnetic sensor.
According to an aspect of the present invention, there is provided an NV color center magnetic sensor including:
the laser current source is connected with the probe module and is used for providing driving current for the probe module so that the probe module generates a laser signal;
the probe module is connected with the probe module and used for providing a composite microwave signal for the probe module, the probe module comprises an NV color center, and the NV color center is used for generating a fluorescent signal according to the laser signal and the composite microwave signal;
the composite microwave signal is formed by superposing a first microwave signal and a second microwave signal, the frequencies of the first microwave signal and the second microwave signal are different, and the phases of the first microwave signal and the second microwave signal are different, so that the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value;
the temperature drift coefficient is used for representing the temperature drift signal amplitude of the NV color center magnetic sensor along with the temperature change.
Optionally, the temperature drift coefficient of the NV color center magnetic sensor is equal to 0.
Optionally, in the first microwave signal and the second microwave signal, one has a phase between 0 ° -90 °, and the other has a phase between 90 ° -180 °;
the power of the first microwave signal and the power of the second microwave signal are different.
Optionally, the microwave module comprises a frequency synthesis unit, a first signal processing unit, a second signal processing unit and a combiner;
the frequency synthesis unit is used for generating a first reference signal according to a clock signal and a first modulation signal and generating a second reference signal according to the clock signal and a second modulation signal;
the input end of the first signal processing unit is connected with the first output end of the frequency synthesis unit and is used for processing the first reference signal to generate a first microwave signal;
the input end of the second signal processing unit is connected with the second output end of the frequency synthesis unit and is used for processing the second reference signal to generate a second microwave signal;
the first input end of the combiner is connected with the output end of the first signal processing unit, the second input end of the combiner is connected with the output end of the second signal processing unit, and the combiner is used for superposing the first microwave signal and the second microwave signal into the composite microwave signal and outputting the composite microwave signal from the output end of the combiner.
Optionally, the frequency synthesis unit includes a direct digital frequency synthesizer, the first signal processing unit includes a first phase-locked loop circuit and a first power amplifier, and the second signal processing unit includes a second phase-locked loop circuit and a second power amplifier;
the first input end of the direct digital frequency synthesizer is connected with the clock signal, the second input end of the direct digital frequency synthesizer is connected with the first modulation signal, the third input end of the direct digital frequency synthesizer is connected with the second modulation signal, the first output end of the direct digital frequency synthesizer is connected with the input end of the first phase-locked loop circuit, and the second output end of the direct digital frequency synthesizer is connected with the input end of the second phase-locked loop circuit;
the output end of the first phase-locked loop circuit is connected with the input end of the first power amplifier, the output end of the first power amplifier is connected with the first input end of the combiner, the output end of the second phase-locked loop circuit is connected with the input end of the second power amplifier, the output end of the second power amplifier is connected with the second input end of the combiner, and the output end of the combiner is connected with the probe module.
According to another aspect of the present invention, there is provided a temperature drift compensation method for an NV color heart magnetic sensor, including:
controlling a laser current source to provide driving current to a probe module so that the probe module generates a laser signal;
the control microwave module generates a composite microwave signal formed by overlapping the first microwave signal and the second microwave signal so that the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value; the first microwave signal and the second microwave signal have different frequencies, phases of the first microwave signal and the second microwave signal are different, and the temperature drift coefficient is used for representing the temperature drift signal amplitude of the NV color center magnetic sensor along with the temperature change condition;
and controlling the NV color center in the probe module to generate a fluorescent signal according to the laser signal and the composite microwave signal.
Optionally, the control microwave module generates a composite microwave signal formed by overlapping the first microwave signal and the second microwave signal, so that a temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value, and the method includes:
controlling the microwave module to generate the first microwave signal and the second microwave signal with equal power and 180 degrees phase difference, and overlapping the first microwave signal and the second microwave signal into the composite microwave signal;
under the same temperature change, calculating the temperature drift coefficient of the NV color center magnetic sensor according to the temperature drift signal amplitude under the first microwave signal and the temperature drift signal amplitude under the second microwave signal;
adjusting the power ratio of the first microwave signal to the second microwave signal to a preset power ratio so that the temperature drift coefficient of the NV color center magnetic sensor meets a preset condition;
and respectively adjusting the phases of the first microwave signal and the second microwave signal based on the preset power ratio until the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value.
Optionally, the adjusting the power ratio of the first microwave signal and the second microwave signal to a preset power ratio so that the temperature drift coefficient of the NV color center magnetic sensor meets a preset condition includes:
sequentially adjusting the power of the first microwave signal and/or the second microwave signal with a fixed step length to change the power ratio;
when the temperature drift coefficient after the power ratio is adjusted for the nth time is smaller than the temperature drift coefficient after the power ratio is adjusted for the nth-1 time and the (n+1) th time, determining that the power ratio adjusted for the nth time is the preset power ratio; wherein n is an integer of 2 or more.
Optionally, the adjusting the phases of the first microwave signal and the second microwave signal based on the preset power ratio until the temperature drift coefficient of the NV color center magnetic sensor is less than or equal to a preset value includes:
adjusting the phase of the first microwave signal with a first preset step length and/or adjusting the phase of the second microwave signal with a second preset step length under the preset power ratio;
and when the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value, determining the phase of the first microwave signal and the phase of the second microwave signal.
Optionally, when the temperature drift coefficient of the NV color center magnetic sensor is less than or equal to a preset value, determining the phase of the first microwave signal and the phase of the second microwave signal includes:
and when the temperature drift coefficient of the NV color center magnetic sensor is equal to 0, determining the phase of the first microwave signal and the phase of the second microwave signal.
According to the technical scheme provided by the embodiment of the invention, the NV color center is controlled by generating the composite microwave signal formed by superposing the first microwave signal and the second microwave signal through the microwave module, and the NV color center generates a fluorescent signal under the composite microwave signal and the laser signal. The frequencies of the first microwave signal and the second microwave signal are different, and the phases of the first microwave signal and the second microwave signal are different, so that the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value. Compared with the prior art, the technical scheme provided by the embodiment has the advantages that the phases of the first microwave signal and the second microwave signal corresponding to the two different resonance frequencies of the NV color center are different, so that the temperature drift signal amplitude of the NV color center under the first microwave signal and at least part of the temperature drift signal amplitude under the second microwave signal can be mutually offset, the temperature drift coefficient of the NV color center magnetic sensor is reduced, and the measurement accuracy of the NV color center sensor is improved.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a structure of an NV color center magnetic sensor according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a curve of NV color center signal amplitude according to a microwave frequency according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a curve of NV color center signal amplitude with temperature according to an embodiment of the present invention;
FIG. 4 is a graph showing the change of fluorescence intensity of an NV color center with microwave frequency according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a microwave module according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of another microwave module according to an embodiment of the present invention;
FIG. 7 is a flowchart of a temperature drift compensation method for an NV color center magnetic sensor according to an embodiment of the present invention;
fig. 8 is a flowchart of another temperature drift compensation method for an NV color center magnetic sensor according to an embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Fig. 1 is a schematic structural diagram of an NV color heart magnetic sensor according to an embodiment of the present invention, and referring to fig. 1, the NV color heart magnetic sensor includes:
a laser current source 10 and a probe module 20, the laser current source 10 being connected to the probe module 20 for providing a driving current to the probe module 20 so that the probe module 20 generates a laser signal;
the microwave module 30 is connected with the probe module 20 and is used for providing a microwave signal to the probe module 20, and the probe module 20 comprises an NV color center 203, and the NV color center 203 is used for generating a fluorescent signal according to the laser signal and the composite microwave signal.
In this embodiment, the composite microwave signal is formed by overlapping a first microwave signal MS1 and a second microwave signal MS2, frequencies of the first microwave signal MS1 and the second microwave signal MS2 are different, and phases of the first microwave signal MS1 and the second microwave signal MS2 are different, so that a temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value. The temperature drift coefficient is used for representing the temperature drift signal amplitude of the NV color center magnetic sensor along with the temperature change condition. For example, the first microwave signal MS1 and the second microwave signal MS2 may be generated by the microwave generator 301 and superimposed to be output via the combiner 302.
Fig. 2 is a schematic diagram of a curve of NV color center signal amplitude changing with microwave frequency according to an embodiment of the present invention, wherein a solid line represents a corresponding relationship between the signal amplitude of the NV color center 203 and the microwave frequency under normal conditions, and a dotted line represents a corresponding relationship between the signal amplitude of the NV color center 203 and the microwave frequency after temperature change. Fig. 3 is a schematic diagram of a curve of NV color center signal amplitude along with temperature change provided in an embodiment of the present invention, referring to fig. 2 and fig. 3, under the same temperature change, under the first microwave signal MS1, the NV color center 203 undergoes positive temperature drift, that is, the signal amplitude of the NV color center 203 becomes larger; in the second microwave signal MS2, which is different from the first microwave signal MS1 in both frequency and phase, the NV color center undergoes a negative temperature drift, i.e. the signal amplitude of the NV color center 203 becomes smaller. Therefore, the superposition output of the first microwave signal MS1 and the second microwave signal MS2 controls the NV color center 203, so that at least part of positive temperature drift and negative temperature drift cancel each other, thereby reducing the temperature drift signal amplitude of the NV color center 203 and further reducing the temperature drift coefficient of the NV color center magnetic sensor.
The frequency of the first microwave signal MS1 and the frequency of the second microwave signal MS2 are both resonance frequencies of the NV color center 203, and by adjusting the phase of the first microwave signal MS1 and the phase of the second microwave signal MS2, the temperature drift coefficient of the NV color center magnetic sensor can be smaller than or equal to a preset value, so as to reduce the temperature drift coefficient of the NV color center magnetic sensor to be within the requirement.
According to the technical scheme provided by the embodiment, the NV color center is controlled by generating a composite microwave signal formed by overlapping the first microwave signal and the second microwave signal through the microwave module, and the NV color center generates a fluorescent signal under the composite microwave signal and the laser signal. The frequencies of the first microwave signal and the second microwave signal are different, and the phases of the first microwave signal and the second microwave signal are different, so that the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value. Compared with the prior art, the technical scheme provided by the embodiment has the advantages that the phases of the first microwave signal and the second microwave signal corresponding to the two different resonance frequencies of the NV color center are different, so that the temperature drift signal amplitude of the NV color center under the first microwave signal and at least part of the temperature drift signal amplitude under the second microwave signal can be mutually offset, the temperature drift coefficient of the NV color center magnetic sensor is reduced, and the measurement accuracy of the NV color center sensor is improved.
Optionally, with continued reference to fig. 1, the probe module 20 further includes a laser diode 201, a beam splitter prism 202, a radiation structure 204, a condensing lens 205, a first photodetector 206 and a second photodetector 207, where the laser diode 201 is connected to the laser current source 10 and is used to generate a laser signal under the action of a driving current, the laser signal is split into two outputs through the beam splitter prism 202, one output is output to the NV color center 203, the other output is output to the first photodetector 206, and the first photodetector 206 is used to convert the laser signal into a corresponding laser signal. The radiation structure 204 is used for transmitting the composite microwave signal output by the microwave module 30 to the NV color center 203. The NV color center 203 generates a fluorescence signal under the excitation of the laser signal and the composite microwave signal, and collects the fluorescence signal through the condensing lens 205, and the second photodetector 2047 is used for converting the fluorescence signal into a corresponding fluorescence electrical signal. Wherein the fluorescence signal can map the fluorescence intensity, which is related to the measured magnetic field.
The NV color center magnetic sensor further comprises a lock-in amplifier 40 and a control module 50, wherein the lock-in amplifier 40 is respectively connected with the probe module 20, the control module 50 and the microwave module 30, and the control module 20 is also connected with the microwave module 30 and the laser current source 10. The lock-in amplifier 40 may be configured to output a fluorescence demodulation signal and a laser demodulation signal based on the received laser electrical signal and the fluorescence electrical signal, and the control module 50 determines the magnetic field strength based on the received laser demodulation signal and the fluorescence demodulation signal.
The lock-in amplifier 40 is also used to output a modulated signal to the microwave module 30 to modulate the microwave signal to output a microwave signal of a specific frequency and phase.
Fig. 4 is a schematic diagram of a curve of a change in fluorescence intensity of an NV color center along with a change in microwave frequency according to an embodiment of the present invention, where the waveform shown in fig. 4 is a correspondence between fluorescence intensity and microwave frequency in an unmodulated state of a fluorescence signal, a solid line indicates a correspondence between fluorescence intensity of an NV color center 203 and microwave frequency under normal conditions, and a dotted line indicates a correspondence between fluorescence intensity of an NV color center 203 and microwave frequency after a temperature change. The waveform shown in fig. 2 is the correspondence between the NV color center signal amplitude and the microwave frequency after the fluorescent signal modulation. In the waveform shown in fig. 4, the NV color center absorption peak slope satisfies the formula (1):
wherein S (Δ) represents fluorescence intensity; delta represents the offset frequency, resulting from the variation of the magnetic induction; c represents the absorption peak contrast; gamma represents the absorption peak linewidth.
C and gamma satisfy the relationship of equation (2):
wherein Ω is the frequency of the NV color center when the Lawster oscillation occurs, is related to the microwave power, and is proportional to the 0.5 th power of the microwave power; Γ -shaped structure p For electron transition rate corresponding to laser power Γ s Is the electron fall-back rate corresponding to the laser power, gamma 1 For the line width of the absorption peak corresponding to the first microwave signal MS1, gamma 2 The absorption peak line width corresponding to the second microwave signal MS2.
When the microwave frequency modulation is introduced, the NV color center is near the resonance frequencyCan be expressed by the formula (3):
where D is the signal amplitude output by the lock-in amplifier 40 and k is the modulation depth of the microwave module 30.
Substituting the formula (2) into the formula (3) can obtain that the signal peak slope of the NV color center is proportional to the microwave power to the power of 0.5 when the microwave frequency is smaller, and inversely proportional to the microwave power when the microwave frequency is larger. And according to the phase-sensitive detection principle, the slope of the signal peak is always proportional to the cosine of the microwave frequency modulation phase. Taking the case of a smaller microwave power as an example, when two microwave signals of different frequencies are applied to the NV color center, if the temperature changes, the temperature drift signal amplitude of the NV color center sensor satisfies the formula (4):
wherein,is the temperature drift signal amplitude, T is the diamond temperature, TC NV Is the temperature drift coefficient of NV color center resonance frequency, K is the conversion coefficient between the signal amplitude and the offset frequency delta, < ->For modulating the phase, the upper corner mark (1) represents the first microwave signal MS1 and the upper corner mark (2) represents the second microwave signal MS2.
Since the first microwave signal MS1 and the second microwave signal MS2 excite the same diamond, K is therefore (1) And K (2) Equality only by making P MW (1) And P MW (2) Equal, phase of the first microwave signal MS1And the phase of the second microwave signal MS2 +.>180 DEG different, can make +.>Therefore, the temperature drift coefficient of the NV color center magnetic sensor is equal to 0, and the temperature drift resistance function is realized.
Alternatively, in practical applications, the emission efficiency of the microwave module 30 is often related to the microwave frequency, and the different frequencies have different emission efficiencies, resulting in unequal microwave power, and therefore, under the limitation of the above factors, K (1) And K (2) Nor are they exactly equal.
In the present embodiment, the power of the first microwave signal MS1 and the power of the second microwave signal MS2 are different, and in the first microwave signal MS1 and the second microwave signal MS2, one is between 0 ° and 90 ° and the other is between 90 ° and 180 °. The temperature drift coefficient of the NV color center magnetic sensor is equal to 0 by adjusting the power ratio of the first microwave signal MS1 to the second microwave signal MS2 and adjusting the phase difference between the first microwave signal MS1 and the second microwave signal MS2 to be 180 degrees or close to 180 degrees, so that the influence of temperature change on the signal amplitude output by the NV color center magnetic sensor is completely eliminated.
It should be understood that the signal amplitudes mentioned in the above embodiments refer to signal amplitudes corresponding to the fluorescence signal output by the NV color center magnetic sensor.
Fig. 5 is a schematic structural diagram of a microwave module according to an embodiment of the present invention, and referring to fig. 1 and fig. 5, based on the above embodiments, a microwave module 30 includes a frequency synthesis unit 311, a first signal processing unit 312, a second signal processing unit 313, and a combiner 302; the frequency synthesizing unit 311, the first signal processing unit 312, and the second signal processing unit 313 form the microwave generator 301. The frequency synthesis unit 311 is configured to generate a first reference signal RS1 according to the clock signal and the first modulation signal, and generate a second reference signal RS2 according to the clock signal and the second modulation signal; an input end of the first signal processing unit 312 is connected to a first output end of the frequency synthesizing unit 311, and is configured to process the first reference signal RS1 to generate a first microwave signal MS1; an input end of the second signal processing unit 313 is connected to a second output end of the frequency synthesizing unit 311, and is configured to process the second reference signal RS2 to generate a second microwave signal MS2; the first input end of the combiner 302 is connected to the output end of the first signal processing unit 312, the second input end of the combiner 302 is connected to the output end of the second signal processing unit 313, and the combiner 302 is configured to superimpose the first microwave signal MS1 and the second microwave signal MS2 into a composite microwave signal, and output the composite microwave signal from its own output end.
Fig. 6 is a schematic structural diagram of another microwave module according to an embodiment of the present invention, referring to fig. 6, optionally, the frequency synthesis unit 311 includes a direct digital frequency synthesizer (Direct Digital Synthesizer, DDS) 3110, the first signal processing unit 312 includes a first phase-locked loop circuit 3011 and a first power amplifier 3013, and the second signal processing unit 313 includes a second phase-locked loop circuit 3012 and a second power amplifier 3014. A first input end of the direct digital frequency synthesizer 3110 is connected to the clock signal, a second input end is connected to the first modulation signal, a third input end is connected to the second modulation signal, a first output end is connected to an input end of the first phase-locked loop circuit 3011, and a second output end is connected to an input end of the second phase-locked loop circuit 3012; an output end of the first phase-locked loop circuit 3011 is connected to an input end of the first power amplifier 3013, an output end of the first power amplifier 3013 is connected to a first input end of the combiner 302, an output end of the second phase-locked loop circuit 3012 is connected to an input end of the second power amplifier 3014, an output end of the second power amplifier 3014 is connected to a second input end of the combiner 302, and an output end of the combiner 302 is connected to the probe module 20.
Specifically, the DDS has the advantages of low cost, low power consumption, high resolution, fast switching time, and the like, and the reference signals (the first reference signal RS1 and the second reference signal RS 2) output by the DDS are used as the excitation of the phase-locked loop circuits (the first phase-locked loop circuit 3011 and the second phase-locked loop circuit 3012), and the phase-locked loop circuits can be regarded as frequency multipliers, so that signal output with different frequencies is realized. The first power amplifier 3013 is configured to power-amplify a signal output from the first phase-locked loop circuit 3011, and the second power amplifier 3014 is configured to power-amplify a signal output from the second phase-locked loop circuit 3012.
Optionally, the embodiment of the invention further provides a temperature drift compensation method of the NV color heart magnetic sensor, which can be used for compensating the temperature drift of the NV color heart magnetic sensor provided by any embodiment. Fig. 7 is a flowchart of a temperature drift compensation method of an NV color heart magnetic sensor according to an embodiment of the present invention, and referring to fig. 7, the compensation method includes:
s110, controlling a laser current source to provide driving current for the probe module so that the probe module generates a laser signal.
S120, controlling a microwave module to generate a composite microwave signal formed by overlapping a first microwave signal and a second microwave signal so that the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value; the first microwave signal and the second microwave signal have different frequencies, and the phases of the first microwave signal and the second microwave signal are different, and the temperature drift coefficient is used for representing the temperature drift signal amplitude of the NV color center magnetic sensor along with the temperature change condition.
And S130, controlling an NV color center in the probe module to generate a fluorescent signal according to the laser signal and the composite microwave signal.
According to the technical scheme provided by the embodiment, the NV color center is controlled by generating a composite microwave signal formed by overlapping the first microwave signal and the second microwave signal through the microwave module, and the NV color center generates a fluorescent signal under the composite microwave signal and the laser signal. The frequencies of the first microwave signal and the second microwave signal are different, and the phases of the first microwave signal and the second microwave signal are different, so that the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value. Compared with the prior art, the technical scheme provided by the embodiment has the advantages that the phases of the first microwave signal and the second microwave signal corresponding to the two different resonance frequencies of the NV color center are different, so that the temperature drift signal amplitude of the NV color center under the first microwave signal and at least part of the temperature drift signal amplitude under the second microwave signal can be mutually offset, the temperature drift coefficient of the NV color center magnetic sensor is reduced, and the measurement accuracy of the NV color center sensor is improved.
Fig. 8 is a flowchart of another temperature drift compensation method for an NV color center magnetic sensor according to an embodiment of the present invention, and referring to fig. 8, the compensation method includes:
s110, controlling a laser current source to provide driving current for the probe module so that the probe module generates a laser signal.
S1201, controlling a microwave module to generate a first microwave signal and a second microwave signal with equal power and 180 DEG phase difference, and overlapping the first microwave signal and the second microwave signal into a composite microwave signal.
Specifically, in connection with fig. 1, the power of the first microwave signal MS1 and the power of the second microwave signal MS2 generated by the microwave module 30 are set to be equal, and the phase difference is 180 °, for example, the phase of the first microwave signal MS1 is 0 °, and the phase of the second microwave signal MS2 is 180 °. The first microwave signal MS1 and the second microwave signal MS2 are outputted in a superimposed manner by the combiner 302.
S1202, under the same temperature change, calculating the temperature drift coefficient of the NV color center magnetic sensor according to the temperature drift signal amplitude under the first microwave signal and the temperature drift signal amplitude under the second microwave signal.
Specifically, the temperature drift signal amplitude of the NV color center 203 under the control of the first microwave signal MS1 and the temperature drift signal amplitude under the control of the second microwave signal MS2 are calculated under the same temperature variation. Taking the example that the frequency of the first microwave signal MS1 is smaller than that of the second microwave signal MS2, referring to fig. 2 and 3, under the same temperature change, the signal amplitude output by the NV color center 203 under the control of the first microwave signal MS1 with smaller frequency drifts in the positive direction, and the signal amplitude output under the control of the second microwave signal MS2 with larger frequency drifts in the negative direction. The temperature drift signal amplitude (drift amount of signal amplitude) under two microwave signals is measured respectively, and the temperature drift signal amplitude of the NV color center magnetic sensor under the control of the composite microwave signal is calculated according to the formula (4) in the embodimentAnd according to the temperature drift signal amplitude +.>And calculating the temperature drift coefficient by the ratio of the temperature variation. The temperature drift coefficient obtained at this time is not equal to 0.
And S1203, adjusting the power ratio of the first microwave signal and the second microwave signal to a preset power ratio so that the temperature drift coefficient of the NV color center magnetic sensor meets a preset condition.
Keeping the phase difference between the first microwave signal MS1 and the second microwave signal MS2 unchanged (the phase difference is 180 degrees), adjusting the power of the first microwave signal MS1 and the second microwave signal MS2, and increasing or decreasing the power ratio to coarsely adjust the temperature drift signal amplitudeUntil the temperature drift coefficient meets the preset condition. The preset condition may be that the temperature drift coefficient is minimum when the adjustment power ratio is adjusted to the preset power ratio.
The step S1203 specifically includes:
sequentially adjusting the power of the first microwave signal MS1 and the second microwave signal MS2 in a fixed step length to change the power ratio;
when the temperature drift coefficient after the power ratio is adjusted for the nth time is smaller than the temperature drift coefficient after the power ratio is adjusted for the nth-1 time and the (n+1) th time, determining the power ratio adjusted for the nth time as a preset power ratio; wherein n is an integer of 2 or more.
Specifically, starting from the equal power position of the first microwave signal MS1 and the second microwave signal MS2, the power of the first microwave signal MS1 and/or the second microwave signal MS2 is adjusted with each fixed step to gradually increase or decrease the power ratio, for example, the fixed step may be 1dB. When the temperature drift coefficient after the power ratio is adjusted for the nth time is smaller than the temperature drift coefficient after the power ratio is adjusted for the front and back times (n-1 time and n+1 time), the temperature drift coefficient after the power ratio is adjusted for the nth time is determined to be the smallest, and the preset condition is met. The power ratio after the nth adjustment is used as a preset power ratio and is used as a power adjustment basis of the first microwave signal MS1 and the second microwave signal MS2 to determine the power of the first microwave signal MS1 and the second microwave signal MS2.
And S1204, respectively adjusting the phases of the first microwave signal and the second microwave signal based on a preset power ratio until the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value.
Specifically, after determining the preset power ratio, the power of the first microwave signal MS1 and the second microwave signal MS2 is kept unchanged, and the phases of the first microwave signal MS1 and the second microwave signal MS2 are continuously adjusted, that is, the phases of the first modulation signal and the second modulation signal are adjusted.
For example, at a preset power ratio, the phase of the first microwave signal MS1 is adjusted by a first preset step size, and/or the phase of the second microwave signal MS2 is adjusted by a second preset step size, until the temperature drift coefficient of the NV color center magnetic sensor is less than or equal to a preset value, the phase of the first microwave signal MS1 and the phase of the second microwave signal MS2 are determined. The phase of the first microwave signal MS1 and the phase of the second microwave signal MS2 may be adjusted simultaneously, or only the phase of one of the microwave signals may be adjusted.
Optionally, the first preset step length and the second preset step length may be equal or unequal, and may be specifically set according to an actual temperature drift coefficient.
Alternatively, when the temperature drift coefficient of the NV color center magnetic sensor is equal to 0, the phase of the first microwave signal MS1 and the phase of the second microwave signal MS2 are determined. That is, by finely adjusting the phase of the first microwave signal MS1 and the phase of the second microwave signal MS2, the temperature drift signal amplitude can be madeSo that the temperature drift coefficient is 0, and the influence of temperature change on the amplitude of the signal output by the NV color center 203 is completely eliminated.
And S130, controlling an NV color center in the probe module to generate a fluorescent signal according to the laser signal and the composite microwave signal.
According to the technical scheme provided by the embodiment of the invention, the power ratio of the first microwave signal MS1 to the second microwave signal MS2 is adjusted firstly by taking the fact that the power of the first microwave signal MS1 and the power of the second microwave signal MS2 are equal and the phase difference is 180 degrees as a reference, so that the temperature drift coefficient of the NV color center magnetic sensor is coarsely adjusted, and the temperature drift coefficient of the NV color center magnetic sensor is reduced. When the power ratio is adjusted to the optimal state, keeping the power ratio at the moment as the preset power ratio, continuously adjusting the phases (phase differences) of the first microwave signal MS1 and the second microwave signal MS2 to fine-adjust the temperature drift coefficient of the NV color center magnetic sensor, and further reducing the temperature drift coefficient of the NV color center magnetic sensor until the temperature drift coefficient of the NV color center magnetic sensor is 0. According to the scheme, the temperature drift coefficient of the NV color center magnetic sensor can be reduced, the influence of temperature change on magnetic measurement accuracy is eliminated, and the NV color center magnetic sensor can be applied to a larger environment temperature range.
It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present invention may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present invention are achieved, and the present invention is not limited herein.
The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims (10)

1. An NV color center magnetic sensor, comprising:
the laser current source is connected with the probe module and is used for providing driving current for the probe module so that the probe module generates a laser signal;
the probe module is connected with the probe module and used for providing a composite microwave signal for the probe module, the probe module comprises an NV color center, and the NV color center is used for generating a fluorescent signal according to the laser signal and the composite microwave signal;
the composite microwave signal is formed by superposing a first microwave signal and a second microwave signal, the frequencies of the first microwave signal and the second microwave signal are different, and the phases of the first microwave signal and the second microwave signal are different, so that the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value;
the temperature drift coefficient is used for representing the temperature drift signal amplitude of the NV color center magnetic sensor along with the temperature change.
2. The NV color heart magnetic sensor of claim 1 wherein the temperature drift coefficient of the NV color heart magnetic sensor is equal to 0.
3. The NV colour centre magnetic sensor of claim 1, wherein one of the first and second microwave signals is between 0 ° -90 ° in phase and the other is between 90 ° -180 ° in phase;
the power of the first microwave signal and the power of the second microwave signal are different.
4. The NV color center magnetic sensor of claim 1 wherein the microwave module includes a frequency synthesizing unit, a first signal processing unit, a second signal processing unit, and a combiner;
the frequency synthesis unit is used for generating a first reference signal according to a clock signal and a first modulation signal and generating a second reference signal according to the clock signal and a second modulation signal;
the input end of the first signal processing unit is connected with the first output end of the frequency synthesis unit and is used for processing the first reference signal to generate a first microwave signal;
the input end of the second signal processing unit is connected with the second output end of the frequency synthesis unit and is used for processing the second reference signal to generate a second microwave signal;
the first input end of the combiner is connected with the output end of the first signal processing unit, the second input end of the combiner is connected with the output end of the second signal processing unit, and the combiner is used for superposing the first microwave signal and the second microwave signal into the composite microwave signal and outputting the composite microwave signal from the output end of the combiner.
5. The NV color center magnetic sensor of claim 4 wherein the frequency synthesizing unit comprises a direct digital frequency synthesizer, the first signal processing unit comprises a first phase-locked loop circuit and a first power amplifier, and the second signal processing unit comprises a second phase-locked loop circuit and a second power amplifier;
the first input end of the direct digital frequency synthesizer is connected with the clock signal, the second input end of the direct digital frequency synthesizer is connected with the first modulation signal, the third input end of the direct digital frequency synthesizer is connected with the second modulation signal, the first output end of the direct digital frequency synthesizer is connected with the input end of the first phase-locked loop circuit, and the second output end of the direct digital frequency synthesizer is connected with the input end of the second phase-locked loop circuit;
the output end of the first phase-locked loop circuit is connected with the input end of the first power amplifier, the output end of the first power amplifier is connected with the first input end of the combiner, the output end of the second phase-locked loop circuit is connected with the input end of the second power amplifier, the output end of the second power amplifier is connected with the second input end of the combiner, and the output end of the combiner is connected with the probe module.
6. The temperature drift compensation method of the NV color center magnetic sensor is characterized by comprising the following steps of:
controlling a laser current source to provide driving current to a probe module so that the probe module generates a laser signal;
the control microwave module generates a composite microwave signal formed by overlapping the first microwave signal and the second microwave signal so that the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value; the first microwave signal and the second microwave signal have different frequencies, phases of the first microwave signal and the second microwave signal are different, and the temperature drift coefficient is used for representing the temperature drift signal amplitude of the NV color center magnetic sensor along with the temperature change condition;
and controlling an NV color center in the probe module to generate a fluorescent signal according to the laser signal and the composite microwave signal.
7. The method of claim 6, wherein the controlling the microwave module to generate a composite microwave signal formed by superimposing the first microwave signal and the second microwave signal so that a temperature drift coefficient of the NV color center magnetic sensor is less than or equal to a preset value includes:
controlling the microwave module to generate the first microwave signal and the second microwave signal with equal power and 180 degrees phase difference, and overlapping the first microwave signal and the second microwave signal into the composite microwave signal;
under the same temperature change, calculating the temperature drift coefficient of the NV color center magnetic sensor according to the temperature drift signal amplitude under the first microwave signal and the temperature drift signal amplitude under the second microwave signal;
adjusting the power ratio of the first microwave signal to the second microwave signal to a preset power ratio so that the temperature drift coefficient of the NV color center magnetic sensor meets a preset condition;
and respectively adjusting the phases of the first microwave signal and the second microwave signal based on the preset power ratio until the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value.
8. The method of claim 7, wherein adjusting the power ratio of the first microwave signal and the second microwave signal to a preset power ratio so that the temperature drift coefficient of the NV color heart magnetic sensor satisfies a preset condition comprises:
sequentially adjusting the power of the first microwave signal and/or the second microwave signal with a fixed step length to change the power ratio;
when the temperature drift coefficient after the power ratio is adjusted for the nth time is smaller than the temperature drift coefficient after the power ratio is adjusted for the nth-1 time and the (n+1) th time, determining that the power ratio adjusted for the nth time is the preset power ratio; wherein n is an integer of 2 or more.
9. The method of claim 7, wherein adjusting the phases of the first microwave signal and the second microwave signal based on the preset power ratio until the temperature drift coefficient of the NV color heart magnetic sensor is less than or equal to a preset value comprises:
adjusting the phase of the first microwave signal with a first preset step length and/or adjusting the phase of the second microwave signal with a second preset step length under the preset power ratio;
and when the temperature drift coefficient of the NV color center magnetic sensor is smaller than or equal to a preset value, determining the phase of the first microwave signal and the phase of the second microwave signal.
10. The method of claim 7, wherein determining the phase of the first microwave signal and the phase of the second microwave signal when the temperature drift coefficient of the NV color heart magnetic sensor is equal to or less than a preset value comprises:
and when the temperature drift coefficient of the NV color center magnetic sensor is equal to 0, determining the phase of the first microwave signal and the phase of the second microwave signal.
CN202311871409.6A 2023-12-28 2023-12-28 NV color center magnetic sensor and temperature drift compensation method thereof Pending CN117805703A (en)

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