Device for improving atom coherent population trapping efficiency and implementation method

Abstract

The invention relates to the technical field of quantum measurement, in particular to a device for improving atom coherent population trapping efficiency and an implementation method. Screening candidate frequency points; judging a temporary frequency point; extracting concerned frequency points; correcting a target frequency point; c field and power adjustment; and applying a radio frequency field and performing frequency locking output. According to the invention, the radio frequency sweep frequency operation is carried out at the preset C field current value and the preset radio frequency power in the high-altitude field area, and the real-time collection and analysis of the transmitted light intensity, the internal temperature of the cavity and the external air pressure are combined, so that the target frequency point is screened from the original to-be-determined frequency points in a multi-level and multi-angle manner; and the C-field current and the radio frequency power are dynamically adjusted, so that high-precision locking of the radio frequency output frequency is further realized, the imprisoning efficiency of atom coherent population can be remarkably improved, the adaptive capacity and the compensation capacity of the system to external disturbance are enhanced, and the system has relatively high environmental robustness and frequency stability.

Description

Technical Field

[0001] The present invention relates to the field of quantum measurement technology, and in particular to a device and implementation method for improving atomic coherent population trapping efficiency. Background Art

[0002] With the rapid development of modern precision metrology and quantum information science, atomic frequency standards, as core components of high-precision time and frequency benchmarks, are widely used in fields such as navigation and positioning, communication synchronization, and fundamental physics research. However, due to complex environmental conditions, especially in high-altitude field environments, the frequency locking accuracy and system stability of atomic coherent population trapping processes face numerous challenges, seriously affecting the short-term stability and overall performance of frequency standards.

[0003] Chinese patent application publication number: CN104410416A, discloses a coherently populated trapped atomic frequency standard and a method for improving its short-term stability. The method includes: detecting the system relaxation time Δt of the atomic frequency standard; using the output frequency of a voltage-controlled crystal oscillator to generate a microwave search signal; generating a two-color coherent laser under the modulation of the microwave search signal, and the two-color coherent laser interacting with atoms to generate an optical detection signal; after controlling an optical switch in a physical unit to be turned on for a period of N Δt, controlling a servo loop to perform synchronous phase detection on the optical detection signal generated by the physical unit to generate a synchronous phase detection signal, where N is an odd number greater than 0; and generating a correction voltage based on the synchronous phase detection signal to act on the voltage-controlled crystal oscillator.

[0004] It can be seen that the coherently populated trapped atomic frequency standard and the method for improving its short-term stability have the following problems: the method is highly dependent on the system relaxation time Δt, and there are certain difficulties in accurately measuring and controlling the relaxation time in practical applications, which can easily affect the stability and accuracy of the frequency standard; the voltage-controlled crystal oscillator is used to generate the microwave search signal, and the frequency adjustment range and response speed are limited, which can easily lead to insufficient sensitivity of the frequency adjustment and difficulty in real-time response to the frequency drift caused by environmental changes; the synchronous phase-locking process relies on the fixed time after the optical switch is controlled, and lacks dynamic response to changes in environmental parameters, which can easily lead to a decrease in the accuracy of the phase-locking signal; the entire system does not fully consider the combined effect of multiple complex factors such as external ambient temperature and air pressure, resulting in the short-term stability of the frequency standard being limited in complex environments; the way in which the correction voltage acts on the voltage-controlled crystal oscillator is prone to hysteresis and insufficient adjustment accuracy, which limits the adaptability and stability of the frequency standard in a dynamic environment. Summary of the Invention

[0005] To this end, the present invention provides a device and implementation method for improving the efficiency of atomic coherent population trapping, which is used to overcome the problem of inaccurate frequency locking caused by environmental changes and system response lag in the prior art through multi-parameter data acquisition and frequency offset dynamic analysis.

[0006] To achieve the above objectives, the present invention provides, on the one hand, a method for improving the efficiency of atomic coherent population trapping, comprising: During the RF frequency sweep at a preset C-field current value and preset RF power in a high-altitude field area, the transmitted light intensity corresponding to each frequency point to be determined, the temperature inside the RF cavity, and the ambient air pressure are collected in real time; Determining a plurality of candidate frequency points according to the transmitted light intensity, the temperature, the air pressure, and a preset contrast threshold; Determine a number of temporary frequency points according to the candidate frequency points, the preset ideal frequency and the preset radio frequency noise model; Selecting a number of frequency points of interest based on the temporal variation characteristics of the transmitted light intensity of each of the temporary frequency points; Correcting all the frequency points of interest according to the temperatures corresponding to any two adjacent frequency points of interest to determine a number of target frequency points; Adjusting the preset C-field current value according to the target frequency and the preset center frequency, and adjusting the preset radio frequency power according to the time-series variation characteristics of the temperature and the air pressure based on the adjusted preset C-field current value; Sequentially applying a radio frequency field to each of the target frequency points re-determined after adjusting the preset radio frequency power, and measuring the Zeeman transition resonance peak frequency of the target frequency point to invert and obtain an actual bias magnetic field value; The output frequency of the radio frequency source is determined according to the degree of matching between the actual bias magnetic field value at each target frequency point and the preset theoretical magnetic field.

[0007] Furthermore, the process of determining a plurality of candidate frequency points according to the transmitted light intensity, the temperature, the air pressure, and a preset contrast threshold includes: determining a plurality of contrast values ​​according to the transmitted light intensity, the temperature, and the air pressure corresponding to each of the to-be-determined frequency points; A plurality of candidate frequency points are determined based on a comparison result between the contrast value and the preset contrast threshold.

[0008] Furthermore, the process of determining a plurality of temporary frequency points according to the candidate frequency points, the preset ideal frequency, and the preset radio frequency noise model includes: Determining a number of frequency deviations according to the absolute difference between the candidate frequency point and the preset ideal frequency; Inputting each of the frequency deviations into the preset radio frequency noise model to obtain a number of frequency stabilities; A plurality of temporary frequency points are determined based on a comparison result between the frequency stability and a preset stability threshold.

[0009] Furthermore, the process of selecting a plurality of frequency points of interest according to the temporal variation characteristics of the transmitted light intensity of each temporary frequency point includes: obtain a change data sequence of the transmission light intensity corresponding to each temporary frequency point in a preset screening period over time; calculate a timing statistical feature of the change data sequence to obtain a timing change feature; screen a plurality of the concerned frequency points from all the temporary frequency points based on a comparison result of the timing change feature and a preset timing change threshold.

[0010] Further, the process of correcting all the concerned frequency points according to the temperature corresponding to each arbitrary adjacent two concerned frequency points to determine a plurality of target frequency points includes: determining a plurality of temperature difference values according to the temperature of each concerned frequency point and the temperature of the next concerned frequency point adjacent thereto; determining a plurality of temperature fluctuation values according to the temperature difference values in a preset correction period; determining a plurality of the target frequency points based on a comparison result of the temperature fluctuation values and a preset temperature fluctuation threshold.

[0011] Further, the process of adjusting the preset C-field current value according to the target frequency point and a preset center frequency threshold includes: determining a plurality of target deviation amounts according to the absolute difference between the target frequency point and a preset center frequency; establishing a mapping relationship between the target deviation amount and the C-field current change based on a preset sensitivity model of the C-field response to atomic transition energy level to obtain a plurality of C-field current correction values; superimposing the C-field current correction value on the preset C-field current value to obtain an adjusted C-field current value.

[0012] Further, the process of adjusting the preset radio frequency power according to the timing change features of the temperature and the air pressure includes: determining a plurality of temperature determination values according to the temperature from the initial time to each time in a preset power adjustment period; determining a plurality of air pressure determination values according to the air pressure from the initial time to each time in the preset power adjustment period; adjusting the preset radio frequency power according to all the temperature determination values and all the air pressure determination values.

[0013] Further, the process of adjusting the preset radio frequency power according to all the temperature determination values and all the air pressure determination values includes: determining a change synchronization degree according to all the temperature determination values and all the air pressure determination values; adjusting the preset radio frequency power based on a comparison result of the change synchronization degree and a preset standard synchronization degree.

[0014] Further, the process of determining the output frequency of the radio frequency source according to the matching degree of the actual bias magnetic field value of each target frequency point and the preset theoretical magnetic field comprises: determining that the target frequency point corresponding to the minimum value of the difference between the actual bias magnetic field value and the preset theoretical magnetic field is the output frequency of the radio frequency source.

[0015] In another aspect, the present application also provides a device for improving the efficiency of atomic coherent population trapping, comprising: a packaging shell, the inside of which is provided with a processing unit, a radio frequency cavity in the central region, and a C-field coil arranged around the radio frequency cavity, for integrating and protecting the internal components; a Zeeman coil attached to the outer wall of the packaging shell on both sides, the magnetic field direction of which is perpendicular to the magnetic field direction of the C-field coil, for applying a radio frequency field; a processing unit arranged inside the packaging shell, comprising a collection module, a candidate determination module, a temporary determination module, a screening module, a correction module, an adjustment module, and a locking module; The collection module is used to collect the transmission light intensity, the temperature inside the radio frequency cavity, and the atmospheric pressure of the environment in real time during the process of radio frequency sweeping at a preset C-field current value and a preset radio frequency power in a high-altitude outdoor area for each to-be-determined frequency point. The candidate determination module is used to determine a plurality of temporary frequency points according to each of the candidate frequency points, a preset ideal frequency, and a preset radio frequency noise model. The temporary determination module is used to determine a plurality of temporary frequency points according to the frequency offset of each of the candidate frequency points and the radio frequency noise model. The screening module is used to screen a plurality of concerned frequency points according to the time sequence change characteristics of the transmission light intensity of each of the temporary frequency points. The correction module is used to correct all concerned frequency points according to the temperature corresponding to each of any two adjacent concerned frequency points to determine a plurality of target frequency points. The adjustment module is used to adjust the preset C-field current value according to the target frequency points and a preset center frequency, and to adjust the preset radio frequency power based on the adjusted preset C-field current value according to the time sequence change characteristics of the temperature and the atmospheric pressure. The locking module is used to apply a radio frequency field to each of the target frequency points re-determined after adjusting the preset radio frequency power in turn, to measure the Zeeman transition resonance peak frequency of the target frequency point, to inversely obtain the actual bias magnetic field value, and to determine the output frequency of the radio frequency source according to the matching degree of the actual bias magnetic field value of each target frequency point and the preset theoretical magnetic field.

[0016] Compared with the prior art, the beneficial effects of the present application are that by collecting multiple source physical parameters such as transmitted light intensity, radio frequency cavity temperature and environmental air pressure in real time in high-altitude outdoor areas, a frequency selection and adjustment mechanism is dynamically constructed, factors such as contrast threshold, frequency offset, radio frequency noise model and timing stability are comprehensively considered, the target frequency is selected step by step, and combined with the sensitivity model of atomic transition frequency to magnetic field change, the actual bias magnetic field value is back calculated, and then the output frequency of the radio frequency source is optimized. This method can adaptively compensate for the disturbance of temperature and air pressure on system stability in complex and variable outdoor environments, and by adjusting the C-field current and radio frequency power, the frequency locking process is more accurate and reliable, thereby significantly improving the atomic coherence population and trapping efficiency, and improving the overall performance and stability of the application system such as atomic frequency standard or quantum sensor.

[0017] Further, by coupling the local extremum calculation of the transmitted light intensity with the exponential weighting of the temperature and air pressure factors, a dynamic suppression factor of environmental disturbance is introduced into the contrast value, so that the selection of the candidate frequency not only reflects the strength characteristics of the optical response, but also comprehensively considers the influence of external temperature drift and air pressure fluctuation on system stability. By constructing a weight function in the form of exponential decay, the physical effect of suppressing false judgment of non-resonant frequency points caused by temperature change (such as cavity thermal expansion affecting atomic transition conditions) and air pressure change (such as refractive index disturbance or standing wave mode change) can be achieved, and finally the physical accuracy and environmental adaptability of frequency point identification are improved, thereby providing more reliable foundation support for subsequent frequency locking and magnetic field inversion.

[0018] Further, by introducing the deviation between the candidate frequency and the ideal frequency, and combining the preset radio frequency noise model to evaluate the frequency stability, the credibility of the spectral response and the practicability of the frequency locking can be effectively reflected in the frequency point selection. This process not only considers the absolute deviation of the frequency, but also integrates the statistical characteristics of the frequency domain noise distribution, realizing the transformation from "optical response strength" to "system stable operation ability". By quantitatively processing the mapping relationship between the frequency deviation and the noise model, false frequency point responses caused by background noise, electronic device jitter or temperature drift in the radio frequency system can be suppressed, and the stability and repeatability of the frequency point selection are improved, providing a high-confidence frequency basis for subsequent frequency fine adjustment and magnetic field matching.

[0019] Further, by performing first-order difference and sliding statistical processing on the transmission light intensity change data sequence of each temporary frequency point within the preset screening period, and comparing the obtained time sequence change characteristics with the set threshold, the frequency points greatly affected by external disturbances or system noise can be effectively screened out, thereby retaining the frequency points with higher signal stability and lower volatility as the concerned frequency points. This screening mechanism reflects the close relationship between the dynamic change of transmission light intensity and time stability, and using statistical volatility indicators to quantify the stability of frequency points can enhance the reliability of frequency selection, provide higher precision initial data support for subsequent frequency correction and magnetic field inversion, and help to improve the steady-state maintenance capability and operation consistency of the atomic system as a whole.

[0020] Further, by statistically analyzing the temperature difference between any adjacent concerned frequency points and calculating the standard deviation of the temperature difference value within the preset correction period, the degree of local temperature fluctuation between frequency points can be quantified; further comparing the temperature fluctuation value with the preset temperature fluctuation threshold, only the corresponding frequency points in the region with stable temperature change are retained as target frequency points, effectively excluding unstable frequency points caused by sudden environmental disturbances or local heating effects, ensuring that the final selected target frequency points have good thermal stability, which is conducive to the accuracy and consistency of subsequent frequency locking. The consistency of the physical environment of the frequency point is reflected through the dynamic change trend of the temperature parameter, thereby improving the environmental adaptability of frequency point selection and the long-term running stability of the system as a whole.

[0021] Further, by converting the deviation between the target frequency point and the preset center frequency into the fine tuning amount of the C-field current, fine control of the magnetic field environment is realized. Specifically, by the preset atomic transition response sensitivity model, the target deviation is mapped to the required current correction amount, and based on the correction values of multiple target frequency points, a more stable and accurate adjusted C-field current value is obtained. In this process, the frequency change, magnetic field change and their interaction are strictly described by the physical model, so that the C-field correction does not depend on single-point measurement, but integrates the behavior characteristics of multiple representative frequency points, thereby effectively reducing the influence of instantaneous interference on the frequency locking accuracy, improving the adaptive compensation ability of the system to magnetic field fluctuations, and realizing high-precision C-field control and frequency stability optimization.

[0022] Further, by dynamically monitoring the change amplitude of temperature and air pressure within a preset power adjustment period, calculating the standard deviation thereof to obtain temperature judgment value and air pressure judgment value, and accordingly adaptively adjusting the preset radio frequency power, the rapid response and compensation to external environmental disturbance can be realized. Since the fluctuation of temperature and air pressure directly affects the stability of atomic energy level structure and the radio frequency resonance condition, the judgment value obtained by statistics of the change trend can accurately reflect the potential influence of the current environmental state on the system stability, so that the adjustment of the radio frequency power is more targeted and adaptive, improving the frequency scanning accuracy and resonance recognition efficiency of the system in complex environment, and ensuring the stable transmission and detection sensitivity of the atomic signal.

[0023] Further, by introducing the change synchronization degree index based on Pearson correlation coefficient, the coordinated change degree of temperature and air pressure within a certain period is effectively quantified, and the radio frequency power is dynamically adjusted accordingly. Specifically, when the environmental temperature and air pressure show highly synchronized fluctuation in time scale, it indicates that the external disturbance has systematicness and enhancement trend, and at this time, by amplifying the original radio frequency power according to the relative deviation between the change synchronization degree and the preset standard synchronization degree, the output stability and signal penetration of the system in the interference environment can be improved. The preset synchronization degree adjustment coefficient introduced in the formula provides flexibility for adjustment, so that the adjustment amplitude is controllable and the response is rapid, effectively balancing the relationship between power enhancement and energy consumption control, thereby improving the adaptive ability and environmental robustness of the system.

[0024] Further, by determining the final output frequency of the radio frequency source based on the matching principle of minimum difference between the actual bias magnetic field value and the preset theoretical magnetic field, it is helpful to accurately select the frequency point with the most consistent physical response among multiple target frequency points as the output, so that the radio frequency signal is more consistent with the sensitive response condition of atomic energy level to external magnetic field. This strategy effectively reduces the frequency offset error caused by magnetic field drift, environmental disturbance, etc., thereby improving the frequency stability and output consistency of the system under complex conditions. At the same time, the minimum difference principle as the frequency selection standard has strong adaptability and scalability, which can dynamically match the actual state of the magnetic field in different operating stages, and enhance the fault tolerance of the system to the change of working point.

[0025] Further, by integrating the package shell, the radio frequency cavity, the C-field coil, the Zeeman coil and the multi-functional processing unit, the system has compact structure and integrated functions, and the automatic control and dynamic compensation capabilities are effectively improved. Especially in high-altitude field environment, the environmental parameters such as transmission light intensity, temperature and air pressure are collected in real time, and through multi-level processing procedures such as candidate screening, time sequence change analysis, temperature correction, power regulation and magnetic field inversion, the locked radio frequency output frequency is closer to the best working point of atomic resonance, so as to improve the atomic coherent population efficiency and transition peak stability. Through the linkage adjustment mechanism of temperature and air pressure on radio frequency power, the adaptability of the system to external disturbance is enhanced; through the mapping relationship between C-field current and frequency offset, a more fine feedback regulation channel is established; at the same time, combined with the dynamic correction method of temperature difference between target frequency points, the signal frequency point with more representative physical meaning is identified, and the frequency locking precision and robustness are further improved. Therefore, the device can significantly improve the frequency stability and magnetic field locking precision of the atomic system in complex environment, and is beneficial to improve the overall performance level of the quantum sensor, atomic clock or atomic interference equipment. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Flow chart of the implementation method for improving atomic coherent population trapping efficiency of the embodiment; Figure 2 Determination logic diagram for determining a plurality of candidate frequency points of the embodiment; Figure 3 Determination logic diagram for determining a plurality of temporary frequency points of the embodiment; Figure 4 Structure schematic diagram of the device for improving atomic coherent population trapping efficiency of the embodiment. DETAILED DESCRIPTION

[0027] In order to make the purpose and advantages of the present application clearer and more apparent, the present application will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the present application.

[0028] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application.

[0029] Please refer to Figure 1 The flow chart of the implementation method for improving atomic coherent population trapping efficiency of the embodiment is shown in the figure, on the one hand, the embodiment provides an implementation method for improving atomic coherent population trapping efficiency, which comprises: The transmission light intensity corresponding to each to-be-determined frequency point, the temperature inside the radio frequency cavity, and the atmospheric pressure of the environment are collected in real time in the process of radio frequency sweeping at a preset C-field current value and a preset radio frequency power in a high-altitude field area; A plurality of candidate frequency points are determined according to the transmission light intensity, the temperature, the atmospheric pressure, and a preset contrast threshold value; A plurality of temporary frequency points are determined according to each candidate frequency point, a preset ideal frequency, and a preset radio frequency noise model; A plurality of concerned frequency points are screened out according to the time sequence variation characteristics of the transmission light intensity of each temporary frequency point; All concerned frequency points are corrected according to the temperature corresponding to each arbitrary adjacent two concerned frequency points, to determine a plurality of target frequency points; The preset C-field current value is adjusted according to the target frequency point and a preset center frequency, and the preset radio frequency power is adjusted based on the adjusted preset C-field current value according to the time sequence variation characteristics of the temperature and the atmospheric pressure; A radio frequency field is sequentially applied to each target frequency point re-determined after the preset radio frequency power is adjusted, and the Zeeman transition resonance peak frequency of the target frequency point is measured, to inversely obtain an actual bias magnetic field value; The radio frequency source output frequency is determined according to the matching degree of the actual bias magnetic field value of each target frequency point and a preset theoretical magnetic field.

[0030] In this embodiment, when radio frequency sweeping is performed in a high-altitude field area, a photodetector integrated in a packaging shell is used to collect the transmission light intensity through an atomic gas chamber in real time. The photodetector is coaxially arranged with the laser beam path, and an analog-to-digital conversion circuit is used to convert an analog light intensity signal into a digital signal. At the same time, a high-precision temperature sensor (such as PT100 or thermocouple) arranged in the packaging shell is used to monitor the temperature variation inside the radio frequency cavity, and the environmental atmospheric pressure is measured by a micro atmospheric pressure sensor (such as a MEMS type barometer) installed on the outer wall of the shell. The output signals of the above-mentioned various sensors are collected and synchronously recorded in real time by the acquisition module connected to the processing unit, so that the light intensity, temperature, and atmospheric pressure parameters corresponding to each to-be-determined frequency point can be accurately obtained during the radio frequency scanning process and used for subsequent data analysis and frequency point screening.

[0031] In this embodiment, the preset radio frequency noise model adopts a machine learning model based on random forest regression. By modeling the radio frequency characteristics of different frequency points under various environmental conditions, the frequency stability of each frequency point under specific conditions can be predicted. During the training process, a dataset containing multiple dimensions of features such as frequency, phase noise, frequency drift, radio frequency power, C-field current, radio frequency cavity temperature, and environmental air pressure is collected, and the comprehensive noise score of each frequency point (such as the stability index based on phase noise and frequency jitter) is used as the model label. After feature normalization and parameter optimization, the model can output the frequency noise stability score in real time during system operation based on the current frequency point and environmental parameters, which can be used to assist in screening temporary frequency points and improve the stability and accuracy of the final frequency output.

[0032] In this embodiment, the method of applying a radio frequency field is to apply a radio frequency field to each target frequency point in turn with the adjusted preset radio frequency power value, the preset frequency step interval, and the preset action time parameter.

[0033] The preset frequency step interval refers to the frequency difference between adjacent two scanning frequency points when scanning or applying a radio frequency signal. It depends on the frequency resolution capability of the radio frequency system, the accuracy requirement of the target frequency point, and the linewidth characteristics of the resonance response. It is usually set between 650 Hz and 750 Hz. The smaller the step interval, the higher the resonance peak recognition accuracy, but the longer the scanning time. In this embodiment, the preset frequency step interval is set to 1 Hz, which can accurately capture the Zeeman transition resonance peak while ensuring measurement efficiency and improve the reliability of the inverted magnetic field value.

[0034] The preset action time parameter refers to the duration of applying a radio frequency signal to each frequency point. It depends on the response time of the atomic energy level system, the accumulation requirement of the resonance signal, and the signal-to-noise ratio control requirement. It is usually set between 100 μs and 10 ms. Too short time may result in unobvious resonance signal, and too long time increases the measurement period. In this embodiment, the preset action time parameter is set to 2 ms, which can accelerate the frequency point traversal speed while ensuring the sufficient response of the atomic system, thereby improving the overall detection efficiency.

[0035] The preset contrast threshold is a judgment standard for the light signal response intensity of the candidate frequency point. It depends on the sensitivity of the system to the change of transmitted light intensity and the noise tolerance. It is usually set between 0.1 and 0.5 (unit: normalized contrast). In this embodiment, it is set to 0.25, which can effectively exclude frequency points with large background light interference or unclear signal edges, ensuring that the selected frequency points have sufficient signal recognition degree and physical response reliability.

[0036] The preset ideal frequency is an ideal resonance frequency determined based on atomic transition level theory, and depends on the atomic species (such as rubidium or cesium), the ideal value of the applied bias magnetic field C field, and the transition frequency under zero magnetic field, and is usually set between 6.8 GHz and 9.2 GHz. Taking rubidium 87 as an example, it is set to 6.834682610 GHz in this embodiment, which can provide an accurate theoretical reference benchmark for frequency point screening and frequency stability evaluation.

[0037] The preset theoretical magnetic field is a reference magnetic field value used for matching determination with the actual bias magnetic field obtained by inversion, and depends on the C field coil design parameters, the driving current, and the atomic level Zeeman splitting model, and is usually set between 1 mG and 10 mG (mG is milligauss). In this embodiment, it is set to 10 mG, which can be used to accurately determine whether the target frequency point is within the theoretically allowed bias field range during the final frequency locking process, thereby improving the physical consistency and long-term stability of the frequency output.

[0038] By collecting multiple source physical parameters such as transmitted light intensity, radio frequency cavity temperature, and environmental air pressure in real time in high-altitude field areas, a frequency point selection and adjustment mechanism is dynamically constructed, and factors such as contrast threshold, frequency offset, radio frequency noise model, and timing stability are comprehensively considered, and the target frequency point is selected step by step, and combined with the sensitivity model of the atomic transition frequency to the magnetic field change, the actual bias magnetic field value is inversely deduced, and then the radio frequency source output frequency is optimized. This method can adaptively compensate for the disturbance of temperature and air pressure on system stability in complex and variable field environments, and by adjusting the C field current and the radio frequency power, the frequency locking process is more accurate and reliable, thereby significantly improving the atomic coherent population and trapping efficiency, and improving the overall performance and stability of the application system such as atomic frequency standard or quantum sensor.

[0039] Please refer to Figure 2 As shown in the figure, it is a determination logic diagram for determining a plurality of candidate frequency points in this embodiment. In this embodiment, the process of determining a plurality of candidate frequency points according to the transmitted light intensity, the temperature, the air pressure, and the preset contrast threshold includes: determining a plurality of contrast values according to the transmitted light intensity, the temperature, and the air pressure corresponding to each of the to-be-determined frequency points, C=(Imax-Imin) / (Imax+Imin)×exp(-α×|ΔT| -β×|ΔP|), wherein C is a contrast value, Imax is the maximum value of the transmitted light intensity in a preset local window, Imin is the minimum value of the transmitted light intensity in a preset local window, ΔT is the difference between the temperature and a preset temperature threshold, ΔP is the difference between the air pressure and a preset air pressure threshold, α is a preset temperature adjustment coefficient, and β is a preset air pressure adjustment coefficient; when the contrast value is greater than the preset contrast threshold, the to-be-determined frequency point is determined as a candidate frequency point, so as to determine a plurality of candidate frequency points.

[0040] The preset local window refers to a set of frequency points within a fixed range extending forward and backward from the current pending frequency point during the spectrum scanning process, which depends on the system resolution, frequency sampling accuracy, and spectral variation trend. It is usually set within a range of ±2 to ±10 frequency points, and in this embodiment, it is set to ±5 frequency points, which can effectively capture local transmission intensity changes, thereby improving the sensitivity and accuracy of contrast value calculation.

[0041] The preset temperature threshold refers to a reference temperature value used to measure the degree of temperature deviation during frequency point acquisition, which depends on the internal temperature control stability requirements of the system and the sensitivity of atomic transitions to thermal drift. It is usually set between 65°C and 90°C, and in this embodiment, it is set to 70°C, which can serve as an important benchmark for correcting the impact of temperature disturbance on contrast calculation, improving the stability of frequency point determination.

[0042] The preset air pressure threshold refers to a standard value used to evaluate the amplitude of air pressure changes during frequency point sampling at a specific altitude, which depends on the average air pressure level at the measurement site and the tolerance of the system to air pressure changes. It is usually set between 80kPa and 100kPa, and in this embodiment, it is set to 90kPa, which can be used to compensate for the impact of air pressure changes on light propagation characteristics and resonance stability, ensuring the reliability of contrast determination.

[0043] The temperature adjustment coefficient is used to characterize the suppression strength of temperature changes on the contrast of transmitted light intensity. It depends on the sensitivity of the atomic system to temperature fluctuations, the thermal expansion coefficient of the cavity material used, and the stability design of the cavity, among other factors. It is usually set between 0.01 / °C and 0.2 / °C, with a larger value indicating greater sensitivity to temperature changes. In this embodiment, it is set to 0.05 / °C, which can appropriately suppress false frequency points introduced by temperature fluctuations while ensuring the sensitive response of the system to the resonance peak, improving the stability and robustness of frequency point screening.

[0044] The air pressure adjustment coefficient is used to describe the adjustment strength of environmental air pressure changes on the contrast of transmitted light, which depends on the influence of external air pressure on the cavity sealing, gas refractive index changes, and the stability of the resonant cavity mode. It is usually set between 0.001 / kPa and 0.05 / kPa. In this embodiment, it is set to 0.01 / kPa, which can effectively compensate for the risk of resonance curve distortion caused by air pressure changes in high-altitude outdoor areas, thereby improving the reliability of candidate frequency point identification.

[0045] By coupling the local extremum calculation of the transmitted light intensity with the exponential weighting of the temperature and air pressure factors, a dynamic suppression factor of environmental disturbances is introduced into the contrast value, so that the screening of candidate frequency points not only reflects the strength characteristics of the optical response, but also comprehensively considers the influence of external temperature drift and air pressure fluctuation on the system stability. By constructing a weight function in the form of exponential decay, the false judgment of non-resonant frequency points caused by temperature changes (such as the influence of cavity thermal expansion on atomic transition conditions) and air pressure changes (such as refractive index disturbance or standing wave mode change) can be effectively suppressed, ultimately improving the physical accuracy and environmental adaptability of frequency point identification, thereby providing more reliable foundation support for subsequent frequency point locking and magnetic field inversion.

[0046] Referring to Figure 3 As shown in the figure, it is a determination logic diagram for determining a plurality of temporary frequency points in the embodiment. In the embodiment, the process of determining a plurality of temporary frequency points according to each candidate frequency point, a preset ideal frequency and a preset radio frequency noise model comprises: determining a plurality of frequency deviation amounts according to the absolute difference between the candidate frequency point and the preset ideal frequency; inputting each frequency deviation amount into the preset radio frequency noise model to obtain a plurality of frequency stabilities; and determining a plurality of temporary frequency points according to the contrast results of the frequency stabilities greater than a preset stability threshold.

[0047] The preset stability threshold is a reference parameter for determining whether the stability corresponding to the frequency deviation amount in the radio frequency noise model meets the system requirements, and depends on the phase noise characteristics of the frequency source, the tolerance of the system to frequency drift, and the linewidth characteristics of the target atomic transition. It is usually set between 0.8 and 0.95 (in terms of normalized stability index), and is set to 0.9 in the embodiment, which can effectively filter out frequency points with unstable frequency response or greatly affected by noise, and ensure that the temporary frequency points selected subsequently have higher frequency retention capability and signal consistency in actual operation.

[0048] By introducing the deviation amount between the candidate frequency point and the ideal frequency and combining the preset radio frequency noise model to evaluate the frequency stability, the credibility of the frequency spectrum response and the practicability of the frequency locking can be effectively reflected in the frequency point screening. This process not only considers the absolute deviation of the frequency, but also integrates the statistical characteristics of the frequency domain noise distribution, realizing the evaluation transformation from "optical response strength" to "system stable operation capability". By quantitatively processing the mapping relationship between the frequency deviation amount and the noise model, false frequency point responses caused by background noise, electronic device jitter or temperature drift in the radio frequency system can be suppressed, and the stability and repeatability of frequency point screening can be improved, providing a high-confidence frequency point basis for subsequent frequency fine adjustment and magnetic field matching.

[0049] Specifically, the process of screening a plurality of concerned frequency points according to the time sequence variation characteristics of the transmission light intensity of each temporary frequency point comprises: obtaining a data sequence of the variation of the transmission light intensity of each temporary frequency point with time within a preset screening period; performing first-order difference processing on the data sequence and calculating the standard deviation thereof, and combining the deviation mean of each data point in a preset sliding window from the sliding mean to obtain the time sequence variation characteristics; when the time sequence variation characteristics are less than a preset time sequence variation threshold, determining that the temporary frequency point is a concerned frequency point, so as to screen a plurality of concerned frequency points.

[0050] The preset screening period refers to the total length of time for counting the variation of the transmission light intensity of the temporary frequency point, and is determined by the response time of the system to external disturbances and the evaluation requirement of the stability of the frequency point. Generally, the preset screening period is set to be between 200 ms and 2 s, and is set to 1 s in the embodiment. The preset screening period can ensure that sufficient data samples are obtained without introducing too much environmental fluctuation interference, thereby improving the judgment accuracy of the time sequence stability of the frequency point.

[0051] The preset sliding window refers to the width of the continuous time period for local mean calculation within the screening period, and is determined by the data sampling rate and the requirement of local fluctuation feature recognition. Generally, the preset sliding window is set to be between 50 ms and 500 ms, and is set to 200 ms in the embodiment. The preset sliding window can smooth short-time peak noise while retaining local dynamic information, and is helpful to accurately reflect the short-time stability of the frequency point.

[0052] The preset time sequence variation threshold refers to the lower limit of the variation characteristic value for determining whether the frequency point is stable, and is determined by the system noise level and the fluctuation tolerance of the frequency point. Generally, the preset time sequence variation threshold is set to be between 0.01 and 0.1 (unit: normalized dimensionless value), and is set to 0.03 in the embodiment. The preset time sequence variation threshold can effectively eliminate the frequency points with large transmission light intensity fluctuations within a short time, and only retain the frequency points with stable responses for subsequent inversion and regulation.

[0053] By performing first-order difference and sliding statistical processing on the data sequence of the variation of the transmission light intensity of each temporary frequency point within the preset screening period, and comparing the obtained time sequence variation characteristics with the set threshold, the frequency points greatly affected by external disturbances or system noise can be effectively screened out, thereby retaining the frequency points with high signal stability and low fluctuation as concerned frequency points. This screening mechanism reflects the close relationship between the dynamic variation of the transmission light intensity and the time stability. The frequency point stability is quantified by using the statistical fluctuation index, which can enhance the reliability of frequency selection, provide higher precision initial data support for subsequent frequency correction and magnetic field inversion, and help to improve the steady-state maintenance ability and operation consistency of the atomic system as a whole.

[0054] Specifically, the process of correcting all the concerned frequency points according to the temperature of each arbitrary adjacent two concerned frequency points to determine a plurality of target frequency points comprises: calculating the difference between the temperature of each concerned frequency point and the temperature of the next concerned frequency point adjacent thereto to determine a plurality of temperature difference values; The standard deviation of the temperature difference values in a preset correction period is calculated to determine a plurality of temperature fluctuation values; when the temperature fluctuation values are less than a preset temperature fluctuation threshold, it is determined that the corresponding concerned frequency points are all target frequency points to determine a plurality of target frequency points.

[0055] The preset correction period refers to the length of the time window for statistical analysis of the standard deviation of the temperature difference values in the process of correcting the concerned frequency points, which depends on the change rate of the ambient temperature and the temperature control response ability of the system, and is usually set to be between 5s and 60s. In this embodiment, it is set to 30s, which can ensure the effectiveness of data statistics while suppressing the influence of environmental fluctuations on the stability of frequency point screening, thereby improving the recognition accuracy of the thermal stability of the target frequency points.

[0056] The preset temperature fluctuation threshold refers to the standard deviation threshold of the temperature difference values for determining whether the adjacent concerned frequency points meet the thermal stability requirement, which depends on the sensitivity requirement of the system for frequency stability and the temperature measurement accuracy of the sensor, and is usually set to be between 0.01℃ and 0.1℃. In this embodiment, it is set to 0.05℃, which can effectively exclude unreliable frequency points caused by short-term temperature fluctuations and enhance the environmental robustness of the final locked frequency points.

[0057] By statistically analyzing the temperature difference between any adjacent concerned frequency points and calculating the standard deviation of the temperature difference values in a preset correction period, the degree of local temperature fluctuation between frequency points can be quantified. Further, by comparing the temperature fluctuation value with the preset temperature fluctuation threshold, only the corresponding frequency points in the region with relatively stable temperature changes are retained as target frequency points, which effectively excludes unstable frequency points caused by sudden environmental disturbances or local heating effects, ensuring that the target frequency points selected finally have good thermal stability, which is conducive to the accuracy and consistency of subsequent frequency locking. The consistency of the physical environment of the frequency points is reflected by the dynamic change trend of the temperature parameter, thereby improving the environmental adaptability of frequency point selection and the long-term running stability of the system as a whole.

[0058] Specifically, the process of adjusting the preset C-field current value according to the target frequency point and the preset central frequency threshold comprises: determining a plurality of target deviation amounts Δfi = |fi - f0| according to an absolute difference value between the target frequency point and the preset central frequency, where Δfi is the i-th target deviation amount, fi is the i-th target frequency point, and f0 is the preset central frequency; based on a preset sensitivity model of the C-field response to the atomic transition energy level, a mapping relationship between the target deviation amount and the C-field current change is established, and a plurality of C-field current correction values ΔIi = Δfi / S are obtained, where ΔIi is the i-th C-field current correction value, and S is a preset response sensitivity; the C-field current correction value is superimposed on the preset C-field current value to obtain an adjusted C-field current value I’ = I0 + ΣΔIi, where I’ is the adjusted C-field current value, I0 is the preset C-field current value, and n is the number of target frequency points.

[0059] The preset central frequency is a reference frequency for guiding the adjustment direction of the target frequency point, and is usually the theoretical resonance frequency of a specific atomic transition energy level (such as Zeeman transition) under ideal C-field conditions. Its value depends on the selected atomic species, transition path, and energy level splitting characteristics under the corresponding magnetic field strength condition. It is usually set between tens of hertz (Hz) and hundreds of hertz, and is set to 700 Hz in the present embodiment, which can provide a stable physical reference for frequency point selection and ensure that the subsequent C-field regulation process is carried out around the core physical mechanism, improving the accuracy of resonance recognition and frequency locking.

[0060] The preset response sensitivity is a parameter representing the amount of change in atomic transition frequency caused by a unit change in C-field current, and its unit is megahertz per ampere (MHz / A), which depends on the atomic species used, the Zeeman response characteristics of the transition energy level to the magnetic field, the structure of the radio frequency cavity, and the magnetic field uniformity in the experimental environment, etc. Usually, the sensitivity is set in the range of 0.1 to 2.0 megahertz per ampere, and is set to 1.25 megahertz per ampere in the present embodiment, which can ensure the accuracy of frequency regulation while avoiding excessive adjustment of the magnetic field disturbance, improving the accuracy of C-field current correction and the matching efficiency of system frequency stability.

[0061] The preset sensitivity model refers to an empirical or theoretical model based on atomic physical laws to describe the response relationship of atomic energy level transition frequency to the change of external magnetic field intensity. The model measures the corresponding atomic transition frequency change under different C field currents, and then fits the function relationship between the transition frequency change and the C field current change. The relationship is usually linear, that is, the transition frequency change is proportional to the C field current change within a certain range, and the proportion coefficient is the preset response sensitivity, which represents the atomic transition frequency change caused by unit current change. The sensitivity model is obtained by experiment in the system calibration stage, and has certain stability and universality. It can be used later to inversely deduce the C field current correction value to be adjusted according to the deviation between the target frequency point and the center frequency, so as to realize the magnetic field precision compensation control.

[0062] By converting the deviation between the target frequency point and the preset center frequency into the fine adjustment amount of the C field current, fine control of the magnetic field environment is realized. Specifically, by the preset atomic transition response sensitivity model, the target deviation is mapped to the required current correction amount, and the correction values of multiple target frequency points are averaged and superimposed to obtain a more stable and accurate adjusted C field current value. In this process, the frequency change, the magnetic field change and their interaction are strictly described by the physical model, so that the C field correction is not dependent on single point measurement, but is based on the behavior characteristics of multiple representative frequency points, thereby effectively reducing the influence of instantaneous interference on the frequency locking accuracy, improving the adaptive compensation ability of the system to the magnetic field fluctuation, and realizing high-precision C field control and frequency stability optimization.

[0063] Specifically, the process of adjusting the preset radio frequency power according to the time sequence change characteristics of the temperature and the air pressure comprises: calculating the standard deviation of the temperature from the initial time to each time in the preset power adjustment period to determine a plurality of temperature judgment values; calculating the standard deviation of the air pressure from the initial time to each time in the preset power adjustment period to determine a plurality of air pressure judgment values; and adjusting the preset radio frequency power according to all the temperature judgment values and all the air pressure judgment values.

[0064] The preset power adjustment period refers to the time window length of the system for statistical temperature and air pressure change trend and adjusting the radio frequency power accordingly, which depends on the external environment change rate and the sensitivity requirement of the system to the radio frequency stability. The period is usually set between 5 seconds and 60 seconds, and a too short time may cause the system to adjust frequently, increasing unnecessary power consumption and disturbance; a too long time may delay the response and reduce the adaptability of the system to sudden environmental fluctuations. In this embodiment, it is set to 30 seconds, which can ensure the stability of the radio frequency power while responding to the temperature and air pressure changes in dynamic environments such as high altitude or field, and improving the consistency and resonance detection efficiency of the radio frequency signal.

[0065] By dynamically monitoring the change amplitudes of temperature and air pressure within a preset power adjustment period, calculating the standard deviations thereof to obtain temperature judgment values and air pressure judgment values, and accordingly adaptively adjusting the preset radio frequency power, the rapid response and compensation to external environmental disturbances can be realized. Since the fluctuations of temperature and air pressure directly affect the stability of atomic energy level structure and the radio frequency resonance condition, the judgment values obtained by statistically analyzing the change trends can accurately reflect the potential influence of the current environmental state on the system stability, so that the adjustment of the radio frequency power is more targeted and adaptive, and the frequency scanning accuracy and resonance recognition efficiency of the system in complex environments are improved, and the stable transmission and detection sensitivity of the atomic signal are ensured.

[0066] Specifically, the process of adjusting the preset radio frequency power according to all the temperature judgment values and all the air pressure judgment values comprises: normalizing all the temperature judgment values to obtain a plurality of temperature normalized values, normalizing all the air pressure judgment values to obtain a plurality of air pressure normalized values, calculating the Pearson correlation coefficient of all the temperature normalized values and all the air pressure normalized values, and increasing the preset radio frequency power according to the relative deviation between the change synchronization degree and the preset standard synchronization degree when the change synchronization degree is greater than the preset standard synchronization degree, U' = U x [1 + r x (P - P0) / P0], wherein U' is the increased preset radio frequency power, U is the preset radio frequency power before increase, P is the change synchronization degree, P0 is the preset standard synchronization degree, and r is a preset synchronization degree adjustment coefficient.

[0067] The preset standard synchronization degree is a reference correlation threshold for judging whether the change relationship between temperature and air pressure has a correlation trend, and its value depends on the tolerance of the system to the environmental change linkage effect and the accuracy requirement of the radio frequency power control. It is usually set between 0.3 and 0.9, and a low value corresponds to a more sensitive synchronous change response, and a high value is suitable for more strict fluctuation consistency judgment. In this embodiment, it is set to 0.7, which can ensure that the system has the response capability to typical synchronous disturbances while avoiding excessive adjustment to short-term irregular fluctuations, thereby improving the discrimination accuracy of power regulation.

[0068] The preset synchronization degree adjustment coefficient is a proportional adjustment parameter for controlling the adjustment amplitude of the radio frequency power, and its size depends on the expected control ability of the system design to the dynamic adjustment range of the power and the response characteristics of the power amplifier module. The coefficient is usually set between 0.05 and 0.5, so as to avoid system overload or instability caused by power mutation on the premise of maintaining the adjustment sensitivity. In this embodiment, it is set to 0.2, which can provide moderately enhanced radio frequency power output when the synchronization degree deviates significantly, and enhance the frequency stabilization performance and interference suppression capability of the system under environmental disturbances.

[0069] By introducing a change synchronization degree index based on Pearson correlation coefficient, the degree of coordinated change of temperature and air pressure within a certain period is effectively quantified, and the radio frequency power is dynamically adjusted accordingly. Specifically, when the environmental temperature and air pressure show highly synchronized fluctuations in the time scale, it indicates that the external disturbance has systematicity and enhancement trend. At this time, by amplifying the original radio frequency power according to the relative deviation between the change synchronization degree and the preset standard synchronization degree, the output stability and signal penetration of the system in the interference environment can be improved. The introduction of the preset synchronization degree adjustment coefficient in the formula provides flexibility in adjustment, making the adjustment range controllable and the response rapid, effectively balancing the relationship between power enhancement and energy consumption control, thereby improving the adaptive ability and environmental robustness of the system.

[0070] Specifically, the process of determining the output frequency of the radio frequency source according to the matching degree of the actual bias magnetic field value and the preset theoretical magnetic field of each target frequency point includes: determining that the target frequency point corresponding to the minimum value of the difference between the actual bias magnetic field value and the preset theoretical magnetic field is the output frequency of the radio frequency source.

[0071] By determining the final output frequency of the radio frequency source based on the matching principle of the minimum difference between the actual bias magnetic field value and the preset theoretical magnetic field, it is helpful to accurately select the frequency point with the most consistent physical response in multiple target frequency points as the output, so that the radio frequency signal is more consistent with the sensitive response condition of atomic energy level to external magnetic field. This strategy effectively reduces the frequency offset error caused by magnetic field drift, environmental disturbance, etc., thereby improving the frequency stability and output consistency of the system under complex conditions. At the same time, the minimum difference principle as the frequency selection standard has strong adaptability and scalability, which can dynamically match the actual state of the magnetic field in different operating stages and enhance the fault tolerance of the system to the change of working point.

[0072] Please refer to Figure 4 The structure of the device for improving the efficiency of atomic coherent population trapping is shown in the figure. On the other hand, the device for improving the efficiency of atomic coherent population trapping comprises: The packaging shell 1 is internally provided with a processing unit, a radio frequency cavity in the central region, and a C-field coil surrounding the radio frequency cavity, for integration and protection of internal components; The Zeman coil 2 is attached to the outer wall of the packaging shell 1 on both sides, and the magnetic field direction is perpendicular to the magnetic field direction of the C-field coil, for applying a radio frequency field; The processing unit is arranged inside the packaging shell and includes a collection module, a candidate determination module, a temporary determination module, a screening module, a correction module, an adjustment module, and a locking module; The collection module is used for collecting the transmission light intensity, the temperature inside the radio frequency cavity and the atmospheric pressure of the environment corresponding to each candidate frequency point in real time in the process of radio frequency sweep at a preset C-field current value and a preset radio frequency power in a high-altitude outdoor area. The candidate determination module is connected with the collection module and is used for determining a plurality of temporary frequency points according to each candidate frequency point, a preset ideal frequency and a preset radio frequency noise model. The temporary determination module is connected with the candidate determination module and is used for determining a plurality of temporary frequency points according to the frequency offset of each candidate frequency point and the radio frequency noise model. The screening module is connected with the temporary determination module and the collection module respectively, and is used for screening a plurality of concerned frequency points according to the time sequence variation characteristics of the transmission light intensity of each temporary frequency point. The correction module is connected with the screening module and the collection module respectively, and is used for correcting all concerned frequency points according to the temperature corresponding to each arbitrary adjacent two concerned frequency points, so as to determine a plurality of target frequency points. The adjustment module is connected with the correction module and the collection module respectively, and is used for adjusting the preset C-field current value according to the target frequency point and a preset center frequency, and adjusting the preset radio frequency power based on the adjusted preset C-field current value according to the time sequence variation characteristics of the temperature and the atmospheric pressure. The locking module is connected with the correction module, and is used for applying a radio frequency field to each target frequency point re-determined after the preset radio frequency power is adjusted, measuring the Zeeman transition resonance peak frequency of the target frequency point, inversely obtaining the actual bias magnetic field value, and determining the radio frequency source output frequency according to the matching degree of the actual bias magnetic field value of each target frequency point and a preset theoretical magnetic field.

[0073] By integrating the package shell, the radio frequency cavity, the C-field coil, the Zeeman coil and the multi-functional processing unit, the compact structure and the function integration are realized, and the automatic control and dynamic compensation capabilities of the system are effectively improved. Especially in the high-altitude field environment, the environmental parameters such as the transmission light intensity, the temperature and the air pressure are collected in real time, and through the multi-level processing procedures such as the candidate screening, the time sequence change analysis, the temperature correction, the power regulation and the magnetic field inversion, the locked radio frequency output frequency is closer to the best working point of the atomic resonance, so that the atomic coherent population efficiency and the transition peak stability are improved. Through the linkage adjustment mechanism of the temperature and the air pressure to the radio frequency power, the adaptability of the system to the external disturbance is enhanced, and through the mapping relationship between the C-field current and the frequency offset, a more fine feedback regulation channel is established. At the same time, combined with the dynamic correction method of the temperature difference between the target frequency points, the signal frequency point with more representative physical meaning is identified, and the frequency locking precision and the robustness are further improved. Therefore, the device can significantly improve the frequency stability and the magnetic field locking precision of the atomic system in the complex environment, and is beneficial to improving the overall performance level of the quantum sensor, the atomic clock or the atomic interference equipment.

[0074] The above only describes the preferred embodiments of the present application and is not used to limit the present application; for those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for improving the efficiency of atomic coherent population trapping, characterized in that: include: During the RF frequency sweep at a preset C-field current value and preset RF power in a high-altitude field area, the transmitted light intensity corresponding to each frequency point to be determined, the temperature inside the RF cavity, and the ambient air pressure are collected in real time; Determining a plurality of candidate frequency points according to the transmitted light intensity, the temperature, the air pressure, and a preset contrast threshold; Determine a number of temporary frequency points according to the candidate frequency points, the preset ideal frequency and the preset radio frequency noise model; Selecting a number of frequency points of interest based on the temporal variation characteristics of the transmitted light intensity of each of the temporary frequency points; Correcting all the frequency points of interest according to the temperatures corresponding to any two adjacent frequency points of interest to determine a number of target frequency points; Adjusting the preset C-field current value according to the target frequency and the preset center frequency, and adjusting the preset radio frequency power according to the time-series variation characteristics of the temperature and the air pressure based on the adjusted preset C-field current value; Sequentially applying a radio frequency field to each of the target frequency points re-determined after adjusting the preset radio frequency power, and measuring the Zeeman transition resonance peak frequency of the target frequency point to invert and obtain an actual bias magnetic field value; The output frequency of the radio frequency source is determined according to the degree of matching between the actual bias magnetic field value at each target frequency point and the preset theoretical magnetic field.

2. The method for improving atomic coherent population trapping efficiency according to claim 1, characterized in that: The process of determining a plurality of candidate frequency points according to the transmitted light intensity, the temperature, the air pressure, and a preset contrast threshold comprises: determining a plurality of contrast values ​​according to the transmitted light intensity, the temperature, and the air pressure corresponding to each of the to-be-determined frequency points; A plurality of candidate frequency points are determined based on a comparison result between the contrast value and the preset contrast threshold.

3. The method for improving atomic coherent population trapping efficiency according to claim 2, characterized in that: The process of determining a plurality of temporary frequency points according to the candidate frequency points, the preset ideal frequency, and the preset radio frequency noise model includes: Determining a number of frequency deviations according to the absolute difference between the candidate frequency point and the preset ideal frequency; Inputting each of the frequency deviations into the preset radio frequency noise model to obtain a number of frequency stabilities; A plurality of temporary frequency points are determined based on a comparison result between the frequency stability and a preset stability threshold.

4. The method for improving atomic coherent population trapping efficiency according to claim 3, characterized in that: The process of selecting a number of frequency points of interest based on the temporal variation characteristics of the transmitted light intensity of each temporary frequency point includes: Obtaining a data sequence of changes in the intensity of the transmitted light over time corresponding to each temporary frequency point within a preset screening period; Calculating the time series statistical characteristics of the change data sequence to obtain the time series change characteristics; Based on the comparison result of the time series change feature and the preset time series change threshold, a number of the focus frequency points are screened out from all the temporary frequency points.

5. The method for improving atomic coherent population trapping efficiency according to claim 4, characterized in that: The process of correcting all the frequency points of interest according to the temperatures corresponding to any two adjacent frequency points of interest to determine a plurality of target frequency points includes: Determine a plurality of temperature differences based on the temperature of each of the frequency points of interest and the temperature of the next frequency point of interest adjacent thereto; determining a plurality of temperature fluctuation values ​​according to the temperature difference within a preset correction period; The target frequency points are determined based on a comparison result between the temperature fluctuation value and a preset temperature fluctuation threshold.

6. The method for improving atomic coherent population trapping efficiency according to claim 5, characterized in that: The process of adjusting the preset C-field current value according to the target frequency point and the preset center frequency threshold includes: Determining a plurality of target deviations based on an absolute difference between the target frequency point and a preset center frequency; Based on a preset sensitivity model of the atomic transition energy level response to the C field, a mapping relationship between the target deviation and the C field current change is established to obtain a number of C field current correction values; The C-field current correction value is superimposed on the preset C-field current value to obtain an adjusted C-field current value.

7. The method for improving atomic coherent population trapping efficiency according to claim 6, characterized in that: The process of adjusting the preset radio frequency power according to the temporal variation characteristics of the temperature and the air pressure includes: Determining a plurality of temperature determination values ​​according to the temperature from the initial moment to each moment within a preset power adjustment period; Determining a plurality of air pressure determination values ​​according to the air pressure from the initial moment to each moment within the preset power adjustment period; The preset radio frequency power is adjusted according to all the temperature determination values ​​and all the air pressure determination values.

8. The method for improving atomic coherent population trapping efficiency according to claim 7, characterized in that: The process of adjusting the preset radio frequency power according to all the temperature judgment values ​​and all the air pressure judgment values ​​includes: determining a degree of change synchronization based on all of the temperature determination values ​​and all of the air pressure determination values; The preset radio frequency power is adjusted based on a comparison result between the changed synchronization degree and a preset standard synchronization degree.

9. The method for improving atomic coherent population trapping efficiency according to claim 8, characterized in that: The process of determining the output frequency of the RF source according to the degree of matching between the actual bias magnetic field value at each target frequency point and the preset theoretical magnetic field includes: The target frequency point corresponding to the minimum value of the difference between the actual bias magnetic field value and the preset theoretical magnetic field is determined to be the output frequency of the radio frequency source.

10. A device for improving atomic coherent population trapping efficiency, constructed based on the method for improving atomic coherent population trapping efficiency according to any one of claims 1 to 9, characterized in that: include: The packaging shell houses a processing unit, a radio frequency cavity located in its central area, and a C-field coil arranged around the radio frequency cavity to integrate and protect the internal components; a Zeeman coil attached to both sides of the outer wall of the packaging shell, with its magnetic field direction perpendicular to the magnetic field direction of the C-field coil, for applying a radio frequency field; a processing unit, which is disposed inside the packaging shell and includes a collection module, a candidate determination module, a temporary determination module, a screening module, a correction module, an adjustment module, and a locking module; The acquisition module is used to collect the transmitted light intensity corresponding to each frequency point to be determined, the temperature inside the RF cavity, and the ambient air pressure in real time during the process of performing RF frequency sweeping with a preset C field current value and a preset RF power in a high-altitude field area; The candidate determination module is configured to determine a plurality of temporary frequency points based on the candidate frequency points, a preset ideal frequency, and a preset radio frequency noise model; The temporary determination module is used to determine a number of temporary frequency points according to the frequency offset of each candidate frequency point and the radio frequency noise model; The screening module is used to screen out a number of focus frequencies according to the time series variation characteristics of the transmitted light intensity of each temporary frequency; The correction module is configured to correct all the frequency points of interest according to the temperatures corresponding to any two adjacent frequency points of interest, so as to determine a plurality of target frequency points; The adjustment module is configured to adjust the preset C-field current value according to the target frequency and the preset center frequency, and adjust the preset RF power according to the time-series variation characteristics of the temperature and the air pressure based on the adjusted preset C-field current value; The locking module is used to sequentially apply an RF field to each of the target frequency points re-determined after adjusting the preset RF power, and to measure the Zeeman transition resonance peak frequency of the target frequency point to invert and obtain the actual bias magnetic field value, and to determine the output frequency of the RF source based on the degree of matching between the actual bias magnetic field value of each target frequency point and the preset theoretical magnetic field.

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