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CN-122017694-A - SERF quantum magnetometer sensitivity improving method based on random noise suppression

CN122017694ACN 122017694 ACN122017694 ACN 122017694ACN-122017694-A

Abstract

The invention discloses a sensitivity improving method of a SERF quantum magnetometer based on random noise suppression, and belongs to the technical field of quantum precision measurement. According to the method, an equivalent rotation angle signal is constructed through polarized light splitting differential detection, orthogonal modulation and integral processing are carried out, and a noise-containing detection signal with superimposed random noise is obtained. Then, a chaos detection system based on a Duffing vibrator is introduced, and the system reaches a critical point of chaos and periodic states by adjusting the amplitude of a reference driving signal. And introducing a signal to be detected in a critical state, wherein the transition of the system state is triggered by the change of the weak signal amplitude. And returning the system to a critical state by reversely adjusting the driving amplitude, and inverting according to the variation of the driving amplitude to obtain the real amplitude of the signal to be detected. The invention effectively suppresses random noise of the quantum sensor and remarkably improves the detection sensitivity and stability of the SERF atomic magnetometer under the strong noise background.

Inventors

  • LI SHUN
  • ZHANG HAIFENG

Assignees

  • 北京航空航天大学杭州创新研究院
  • 北京航空航天大学

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. The SERF quantum magnetometer sensitivity improving method based on random noise suppression is characterized by comprising the following steps of: Step 1, obtaining two paths of differential light intensity signals and constructing a time domain rotation angle signal; Step 2, quadrature modulation and integration processing are carried out on the time domain optical rotation angle signal, and two paths of intermediate signals which contain target modulation components and are superimposed with random noise are obtained; step 3, constructing two paths of orthogonal input signals to be detected based on the two paths of intermediate signals, and respectively executing steps 4-8 on the two paths of orthogonal input signals to be detected to obtain two paths of orthogonal amplitude components; Step 4, establishing a chaotic oscillator system under a reference driving signal, wherein the frequency of the reference driving signal is the same as the frequency of the target modulation component; step 5, enabling the chaotic oscillator system to be in a critical state between a chaotic state and a periodic state by adjusting the amplitude of the reference driving signal; step 6, introducing one signal of the orthogonal input signals to be detected into a chaotic oscillator system in a critical state, and recording the state change of the chaotic oscillator system; Step 7, reversely adjusting the amplitude of the reference driving signal based on the state change until the chaotic oscillator system returns to the critical state again, and calculating the driving force amplitude change before and after adjustment; Step 8, inverting the amplitude of a target modulation component contained in one path of signal of the input signal to be detected based on the driving force amplitude variation as one path of quadrature amplitude component; and 9, based on the two paths of orthogonal amplitude components, obtaining final amplitude information of the input signal to be detected through combination operation.
  2. 2. The method for improving sensitivity of a random noise suppression-based SERF quantum magnetometer according to claim 1, wherein the quadrature modulation and integration processing in step 2 specifically comprises: Multiplying the time domain rotation angle signal with a sine signal and a cosine signal with the frequency being the target modulation frequency respectively to obtain two paths of multiplication results; and carrying out integral average on the two paths of multiplication results in a preset time window, wherein the length of the time window is an integer multiple of the corresponding period of the target modulation frequency so as to inhibit non-target frequency components and obtain the two paths of intermediate signals.
  3. 3. The method for improving sensitivity of the SERF quantum magnetometer based on random noise suppression according to claim 2, wherein the construction of two paths of orthogonal input signals to be detected in the step 3 is specifically as follows: and multiplying the two paths of intermediate signals with cosine reference signals with the same frequency respectively to form two paths of input signals to be detected, wherein the input signals are in the form of sine carrier signals and random noise is superimposed on the sine carrier signals, and the carrier frequency of the input signals is the same as the target modulation frequency.
  4. 4. The method for improving sensitivity of a SERF quantum magnetometer based on random noise suppression according to claim 1 is characterized in that the chaotic oscillator system in the step 4 is a Duffing oscillator system, a dynamics equation of the chaotic oscillator system comprises a linear damping term, a negative linear restoring force term, a nonlinear cubic restoring force term and a periodic driving term, and the reference driving signal is a cosine signal with the same frequency as a target modulation component.
  5. 5. The method for improving sensitivity of a random noise suppression-based SERF quantum magnetometer according to claim 1, wherein in the step 5, a maximum disturbance characteristic index of the chaotic oscillator system under the current reference driving signal amplitude is calculated by a numerical method, and the maximum disturbance characteristic index approaches zero as a criterion that the system is in a critical state between a chaotic state and a periodic state.
  6. 6. The method for improving sensitivity of the SERF quantum magnetometer based on random noise suppression according to claim 5, wherein the calculating process of the maximum disturbance characteristic index comprises the following steps: Carrying out numerical integration on a system disturbance equation to solve the system state; in the integration process, performing periodic QR decomposition and orthogonalization on a disturbance matrix representing two linear independent disturbance directions; And accumulating the logarithmic values of diagonal elements of the upper triangular matrix obtained by QR decomposition and calculating time average to obtain the maximum disturbance characteristic index.
  7. 7. The method for improving sensitivity of a SERF quantum magnetometer based on random noise suppression according to claim 1, wherein in the step 7, if the system state is changed from the critical chaotic state to the periodic state after the input signal to be detected is introduced, the system is returned to the critical state by gradually reducing the amplitude of the reference driving signal, and the driving force amplitude variation is the absolute value of the difference between the amplitude of the reference driving signal and the initial critical driving force amplitude when the system returns to the critical state.
  8. 8. The method for improving sensitivity of SERF quantum magnetometer based on random noise suppression according to claim 1, wherein the combination operation in step 9 is specifically that square sum-square operation is performed on the two orthogonal amplitude components to reconstruct the amplitude of the original target modulation component.
  9. 9. An electronic device, comprising: one or more processors; A memory for storing one or more programs; Wherein the one or more programs, when executed by the one or more processors, cause the one or more processors to implement the random noise suppression-based SERF quantum magnetometer sensitivity enhancement method of any of claims 1-8.
  10. 10. A computer readable storage medium having stored thereon executable instructions which when executed by a processor enable the processor to implement the random noise suppression based SERF quantum magnetometer sensitivity enhancement method according to any of claims 1-8.

Description

SERF quantum magnetometer sensitivity improving method based on random noise suppression Technical Field The invention belongs to the technical field of quantum precision measurement, and particularly relates to a sensitivity improving method of a SERF quantum magnetometer based on random noise suppression. Background The atomic magnetometer is a high-sensitivity sub-sensor for realizing magnetic field measurement by utilizing interaction of atomic spins and an external magnetic field. The spin-exchange relaxation free (SERF) atomic magnetometer has extremely high theoretical sensitivity under extremely weak magnetic field conditions, and has important application potential in the fields of biological magnetic signal detection, geomagnetic exploration, basic physical research and the like. SERF atomic magnetometers generally operate based on optical pumping and optical detection principles. The external magnetic field causes precession of the atomic spins, which in turn modulates the plane of polarization of the probe beam, producing an extremely small spin angle signal. The signal is generally extracted by a polarization spectroscopic differential detection method, that is, a pair of photodetectors respectively receive orthogonal polarization components, and an electrical signal proportional to the rotation angle is obtained after differential amplification processing. However, in actual measurement, significant random noise is inevitably present in the detection signal due to various factors such as thermal motion of atoms inside the atomic gas chamber, fluctuation in intensity of pump light and probe light, shot noise of the photodetector, and noise floor of the electronic system. The noise cannot be effectively restrained in the traditional linear demodulation method, so that weak optical rotation angle signals are often submerged, the signal to noise ratio of the finally extracted signals is reduced, and the actual sensitivity of the magnetometer is severely limited. Although noise suppression methods based on statistical properties such as lock-in amplification and digital averaging have been studied, these methods generally rely on specific assumptions about noise distribution, and their performance may be significantly degraded in actual environments where noise statistical properties are unknown or non-stationary. Therefore, the main problem faced by the prior art is how to realize the robust and high-sensitivity detection of the ultra-weak rotation angle signal output by the SERF atomic magnetometer under the background of strong random noise, thereby breaking through the limitation of noise on the final sensitivity of the magnetometer and exerting the theoretical performance of the magnetometer. There is a need for a new signal processing method that does not rely on noise a priori statistical properties and has a high detection sensitivity for weak signals. Disclosure of Invention The invention provides a SERF quantum magnetometer sensitivity improving method based on random noise suppression, which overcomes the problem of insufficient random noise suppression capability of the traditional linear demodulation method by introducing a nonlinear dynamics mechanism with natural robustness to random noise in the signal processing process, thereby realizing high-sensitivity detection on weak signals of a rotation angle and improving the measurement sensitivity of the SERF quantum magnetometer. In order to achieve the above purpose, the invention adopts the following technical scheme: A SERF quantum magnetometer sensitivity improving method based on random noise suppression comprises the following steps: Step 1, obtaining two paths of differential light intensity signals and constructing a time domain rotation angle signal; Step 2, quadrature modulation and integration processing are carried out on the time domain optical rotation angle signal, and two paths of intermediate signals which contain target modulation components and are superimposed with random noise are obtained; step 3, constructing two paths of orthogonal input signals to be detected based on the two paths of intermediate signals, and respectively executing steps 4-8 on the two paths of orthogonal input signals to be detected to obtain two paths of orthogonal amplitude components; Step 4, establishing a chaotic oscillator system under a reference driving signal, wherein the frequency of the reference driving signal is the same as the frequency of the target modulation component; step 5, enabling the chaotic oscillator system to be in a critical state between a chaotic state and a periodic state by adjusting the amplitude of the reference driving signal; step 6, introducing one signal of the orthogonal input signals to be detected into a chaotic oscillator system in a critical state, and recording the state change of the chaotic oscillator system; Step 7, reversely adjusting the amplitude of the reference driving signal based on the stat