CN-121977520-A - Strong pumping bilateral resonance modulation and demodulation magnetic sensitivity enhancement method of quantum magnetic compass

CN121977520ACN 121977520 ACN121977520 ACN 121977520ACN-121977520-A

Abstract

The invention discloses a strong pumping bilateral resonance modulation-demodulation magnetic sensitivity enhancement method of a quantum magnetic compass, which comprises the steps of constructing a quantum magnetic compass platform comprising a sensitive unit and various external optical and microelectronic devices, realizing quantum state enhancement reading of magnetic vector information by using a pumping enhancement mode, initializing a quantum state by using near-saturation external pumping light by using standard diamond and utilizing self thermal conductivity and light transmittance, narrowing line width, improving magnetic measurement sensitivity, filtering noise in an environment by using a modulation-demodulation mode, and realizing high-robustness extraction of quantum information. The laser pump power is enhanced to improve the total fluorescence photon emission speed of the solid-state quantum color center system and the full width at half maximum of the compressed magnetic resonance curve, so that the magnetic field measuring capability of the solid-state quantum color center is improved, and the accurate measurement of external magnetic field signals through the solid-state quantum color center in the diamond is realized.

Inventors

GAO YANJIE
WAN ZHIMIN
Shi Shuijuan
Pu Yuhao
QU LEI
SU HANG
ZHANG HANSHENG
HU QIN

Assignees

南通职业大学

Dates

Publication Date: 20260505
Application Date: 20251219

Claims (8)

1. A strong pumping bilateral resonance modulation demodulation magnetic sensitivity enhancement method of a quantum magnetic compass is characterized by comprising the following steps: step 1, constructing a quantum magnetic compass platform comprising a sensitive unit and various external optical and microelectronic devices; Using standard diamond, utilizing self heat conductivity and light transmittance, using near saturated external pumping light to initialize quantum state, compressing narrow line width and raising magnetic measurement sensitivity; And step 3, filtering noise in the environment by a modulation and demodulation mode, and realizing high-robustness extraction of quantum information.
2. A strong pumping bilateral resonance modulation-demodulation magnetic sensitivity enhancement method of a quantum magnetic compass according to claim 1 is characterized in that a solid-state quantum magnetic compass based on nitrogen vacancies in diamond is specifically characterized in that the processed diamond is used as a sensitive unit, nitrogen elements are permeated into a diamond material cut by a [ 111 ] crystal face or added during growth, then electron irradiation is used for preparing crystal lattice vacancies in the diamond, then high-temperature annealing is used, after the preparation is finished, diamond containing nitrogen vacancy color centers cut by the [ 11 ] is selected as the sensitive unit, pumping light is added to the sensitive unit, fluorescence collection is finished by a parabolic prism, initialization preparation from the nitrogen vacancy color centers to a |0> state is achieved by laser, a sine wave generator and a microwave modulation unit are arranged in a circuit, sine waves are selected as modulation signals, the working conditions are that the amplitude is +/-1V, the frequency is from 1kHz to 1MHz, and then demodulation of fluorescence voltage signals and effective information extraction are achieved through a demodulation circuit.
3. The method for enhancing the magnetic sensitivity of the strong-pumping bilateral resonance modem of the quantum magnetic compass according to claim 2, wherein the pump light is added to the sensitive unit, and a laser and a convex lens are used for realizing color center ensemble excitation of hundred cubic micrometers or a laser is used for realizing color center excitation of cubic millimeter size.
4. A method for enhancing magnetic sensitivity of strong pump bilateral resonance modem of quantum magnetic compass according to claim 1, wherein step 2 comprises the steps of, in a system in which NV color center interacts with pump laser and microwave, optically detecting linear profile of magnetic resonance ODMR to be Lorentz type, increasing with microwave power, spin-spin coupling to result in contrast reduction and linewidth increase of magnetic resonance spectrum, longitudinal and transverse relaxation times of color center electron spin are respectively represented by T 1 and T 2 , corresponding attenuation rates are respectively represented by gamma 2 = 1/T 2 and gamma 1 = 1/T 1 , and electron spin direction under continuous laser pumping and microwave irradiation The transition rate of the states is denoted by Γ p , and in a continuous ODMR measurement the contrast of the magnetic resonance spectrum at each frequency point is related to the detuning amount v-v0, the final spectrum being a lorentz function with respect to the microwave detuning amount v-v0, as shown in the following formula: ; In the equation, S (+_j) represents the contrast when the microwave frequency is far from resonance, C represents the contrast during resonance, v represents the microwave frequency acting on the nitrogen vacancies NV, v 0 represents the resonance frequency of the microwaves, Δv represents the full width at half maximum FWHM, and the full width at half maximum FWHM of the single nitrogen vacancy formants is represented as: ; in the formula, T 2 eff and T 1 eff are effective relaxation times, which depend on the optical pumping rates 1/T 1 eff = 1/T 1 +Γp and 1/T 2 eff = 1/T 2 +Γp, respectively, fr=Ω/(2π) is related to the microwave irradiation power, Ω is the frequency of the NV - electron spin precession, the increase of the microwave power widens the resonance peak, and for sufficiently high microwave powers FWHM is expressed as: ; ; For the NV color center ensemble, T 1 is 3 orders of magnitude higher than T 2 , and because the environment of each NV is different, the overall situation of NV in the diamond is considered, and the color center is in a single state: ; In the middle of For an ODMR signal of single NV, a center frequency V 0 ,P（v 0 ) indicates that the line is of lorentz type, and the FWHM of the collective average ODMR is denoted Δv tot ; ; In the above-mentioned equation(s), , For an effective transverse relaxation time, the assumption is made that the pump laser does not affect the transverse relaxation rate, so that gamma 2 eff ≈γ 2 , in addition, based on gamma 2 eff is significantly smaller than Deltav inh , and this information cannot be obtained from the non-uniformly broadened resonance peak, so this term can be omitted, so that the final equation is: ; Wherein, the For an intrinsic transverse relaxation rate, the smaller the bandwidth of the resonance peak with increasing pump intensity, the higher the FWHM at low laser pumping conditions due to spin-spin interactions.
5. The method for enhancing the magnetic sensitivity of the strong-pumping bilateral resonance modem of the quantum magnetic compass according to claim 1, wherein the step 3 is characterized in that under the working circuit of the phase-locked amplifier, a fluorescent signal is multiplied with a reference signal, and the fluorescent signal can reflect a resonance frequency point through a low-pass filter; ; Wherein V X is a demodulation signal, V I is an input fluorescent voltage signal, V R is a reference signal, ω R is a modulation frequency, θ I is a phase of the fluorescent voltage signal, θ R is an adjustable phase of the reference signal, and t is time; In a typical detection combining ODMR and phase lock, only one frequency of microwave is applied to the NV color center ensemble, two different frequency of microwaves are applied under the support of a locking system tracking a specific frequency, the two different frequency of microwaves respectively correspond to the conversion from ms=0 to ms= -1 and from ms=0 to ms= +1, under the stable power of the two microwaves, one of the two microwaves is assumed to affect a specific proportion of NVs, under the condition that phase lock detection is not carried out, under the condition that two frequencies are simultaneously used in CW-ODMR, the change of fluorescence can not be distinguished, because the two resonant frequencies can lead to the reduction of fluorescence, a signal with the specific frequency is generated by using a locking detection technology to determine the part from which the fluorescence is changed, after the system is measured, a modulating signal generating module outputs two different frequency modulating signals for a microwave source 1 and a microwave source 2, the outputs of the two microwave sources are transmitted through an ohmic antenna near a diamond, a quantum bit is driven to flip, a fluorescent signal obtained by a photoelectric detector is simultaneously transmitted to a demodulation module, and then the two phase-modulated signal input ports are modulated by the two phase-locked detection module, and the two phase-modulated signals are output in opposite directions are effectively extracted by opposite directions.
6. A computer device comprising a memory, a processor and a computer program stored on the memory, characterized in that the processor executes the computer program to carry out the steps of the method of claim 1.
7. A computer readable storage medium having stored thereon a computer program/instruction which when executed by a processor performs the steps of the method of claim 1.
8. A computer program product comprising computer programs/instructions which, when executed by a processor, implement the steps of the method of claim 1.

Description

Strong pumping bilateral resonance modulation and demodulation magnetic sensitivity enhancement method of quantum magnetic compass Technical Field The invention belongs to the technical field of intelligent network-connected automobile-mounted quantum magnetic compasses, and particularly relates to a strong-pumping bilateral resonance modulation-demodulation magnetic sensitivity enhancement method of a quantum magnetic compass. Background With the rapid development of intelligent traffic technology, technologies such as automatic driving, intelligent traffic management and vehicle collaborative driving are increasingly paid attention to by managers and users. The intelligent network-connected automobile needs to rely on high-precision positioning and navigation technology to realize safe and efficient automatic driving functions, however, the traditional navigation system (such as GPS) often has the problems of weak signals, insufficient positioning precision and the like in complex environments (such as urban canyons, tunnels or electromagnetic interference areas), and the strict requirements of the intelligent network-connected automobile on high-precision navigation are difficult to meet. Quantum technology has been vigorously developed in recent years. Under the background, as an emerging high-precision navigation technology, a quantum magnetic compass in the quantum technology is gradually focused by researchers and is suitable for being applied to intelligent network automobiles. The method can realize high-precision measurement of the magnetic field vector through the high-sensitivity characteristic of the quantum state, and provides more reliable navigation support for intelligent network-connected automobiles. However, existing quantum magnetic compasses still face a number of challenges, mainly in the laboratory stage. In vehicle applications, consideration is given to how to achieve high-precision measurements and stable operation in different vehicle driving environments (e.g., complex electromagnetic interference, fast changing magnetic field environments, vehicle vibrations, and variable climatic conditions). In addition, the vehicle-mounted electronic unit needs to have good environment adaptability, the intelligent network-connected automobile is in a changeable environment scene when running, and requirements for equipment to keep a high-precision working state under different environments are set. However, the current quantum magnetic compass device has insufficient capability of extracting effective signals in the aspect of coping with dynamic environment changes, so that the measurement accuracy is reduced, and the safe driving function of the intelligent network-connected automobile is affected. Therefore, a method for extracting the quantum magnetic compass signal with the environment self-adaptation capability is needed, and the accuracy and the reliability of the system are ensured by enhancing signal extraction and effective filtering, so that the actual requirement of the intelligent network-connected automobile on high-accuracy navigation in a complex environment is met. Disclosure of Invention The invention aims to provide a strong pumping bilateral resonance modulation-demodulation magnetic sensitivity enhancement method of a quantum magnetic compass. On the premise of using a common quantum sensitive unit, the line width is reduced, the magnetic information measurement sensitivity is improved, and the noise is reduced and meanwhile the magnetic signal to be measured is effectively extracted by a modulation-demodulation filtering method. The technical scheme is that the strong pumping bilateral resonance modulation demodulation magnetic sensitivity enhancement method of the quantum magnetic compass comprises the following steps: step 1, constructing a quantum magnetic compass platform comprising a sensitive unit and various external optical and microelectronic devices; Using standard diamond, utilizing self heat conductivity and light transmittance, using near saturated external pumping light to initialize quantum state, compressing narrow line width and raising magnetic measurement sensitivity; And step 3, filtering noise in the environment by a modulation and demodulation mode, and realizing high-robustness extraction of quantum information. The method comprises the steps of (1) preparing a solid-state quantum magnetic compass based on nitrogen vacancies in diamond by using processed diamond as a sensitive unit, carrying out infiltration of nitrogen elements in a diamond material cut by a [ 111 ] crystal face or adding nitrogen elements during growth, then using electron irradiation to prepare the crystal vacancies in the diamond, then using high-temperature annealing, after the preparation is finished, selecting the diamond containing the nitrogen vacancy color center cut by the [ 11 ] as the sensitive unit, adding pumping light into the sensitive unit, carrying out fluoresce