Apparatus and implementation method for improving atomic coherent population trapping efficiency

Abstract

The present application relates to the technical field of quantum measurement, and especially relates to a device and method for improving atomic coherent population trapping efficiency, which comprises the following steps: data acquisition; candidate frequency point screening; temporary frequency point determination; concerned frequency point extraction; target frequency point correction; C field and power adjustment; RF field application and frequency locking output. The present application realizes multi-level and multi-angle screening of target frequency points from original undetermined frequency points by carrying out RF sweep operation with preset C field current value and preset RF power in high-altitude field area, and realizes dynamic adjustment of C field current and RF power according to the target frequency points, and further realizes high-precision locking of RF output frequency, which can significantly improve the trapping efficiency of atomic coherent population, enhance the adaptability and compensation ability of the system to external disturbance, and has strong environmental robustness and frequency stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of quantum measurement, and in particular to a device and method for improving atomic coherent population trapping efficiency. BACKGROUND

[0002] With the rapid development of modern precision measurement technology and quantum information science, atomic frequency standards, as the core devices of high-precision time and frequency reference, are widely used in navigation and positioning, communication synchronization, and basic physics research. However, due to the complex environmental conditions, especially in high-altitude outdoor areas, the frequency locking accuracy and system stability in the atomic coherent population trapping process face many challenges, which seriously affect the short-term stability and overall performance of the frequency standard.

[0003] Chinese patent application publication No. CN104410416A discloses a coherent population trapping atomic frequency standard and a method for improving its short-term stability, which comprises: detecting the system relaxation time Δt of the atomic frequency standard; generating a microwave search signal using the output frequency of a voltage-controlled crystal oscillator; generating a two-color coherent laser under the modulation of the microwave search signal, and the two-color coherent laser interacts with the atoms to generate an optical detection signal; after the optical switch in the control physical unit is opened for N Δt time length, the control servo loop synchronously phase detects the optical detection signal generated by the physical unit to generate a synchronous phase detection signal, N is an odd number greater than 0; and generating a correction voltage according to the synchronous phase detection signal and acting on the voltage-controlled crystal oscillator.

[0004] It can be seen that the coherent population trapping atomic frequency standard and the method for improving its short-term stability have the following problems: the method is strongly dependent on the system relaxation time Δt, and it is difficult to accurately measure and control 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 a microwave search signal, and the frequency adjustment range and response speed are limited, which can easily lead to insufficient sensitivity of frequency adjustment and difficulty in real-time response to frequency drift caused by environmental changes; the synchronous phase detection process depends on the fixed time length 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 detection signal; the entire system does not fully consider the combined effect of various complex factors such as temperature and pressure of the external environment, which limits the short-term stability of the frequency standard in complex environments; and the correction voltage acting on the voltage-controlled crystal oscillator can easily have the problems of lag and insufficient adjustment precision, which limits the adaptability and stability of the frequency standard in dynamic environments. SUMMARY

[0005] Therefore, the present application provides a device and method for improving atomic coherent population trapping efficiency, which overcomes the problem of inaccurate frequency locking due to environmental changes and system response lag in the prior art by means of multi-parameter data acquisition and frequency offset dynamic analysis.

[0006] To achieve the above object, in one aspect, the application provides an implementation method for improving atomic coherent population trapping efficiency, comprising:

[0007] In the process of performing radio frequency sweep in a high-altitude field area with preset C-field current value and preset radio frequency power, 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;

[0008] 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;

[0009] A plurality of temporary frequency points are determined according to each of the candidate frequency points, a preset ideal frequency and a preset radio frequency noise model;

[0010] A plurality of concerned frequency points are screened out according to the time sequence variation characteristics of the transmission light intensity of each of the temporary frequency points;

[0011] All concerned frequency points are corrected according to the temperature corresponding to each of any two adjacent concerned frequency points, so as to determine a plurality of target frequency points;

[0012] The preset C-field current value is adjusted according to the target frequency points and a preset center frequency, and the preset radio frequency power is adjusted according to the time sequence variation characteristics of the temperature and the atmospheric pressure based on the adjusted preset C-field current value;

[0013] A radio frequency field is sequentially applied to each of the target frequency points re-determined after the preset radio frequency power is adjusted, and the Zeeman transition resonance peak frequency of the target frequency point is measured, so as to obtain an actual bias magnetic field value by inversion;

[0014] The matching degree of the actual bias magnetic field value of each target frequency point and a preset theoretical magnetic field is determined to determine the output frequency of a radio frequency source.

[0015] Further, the process of determining a plurality of candidate frequency points according to the transmission light intensity, the temperature, the atmospheric pressure and a preset contrast threshold value comprises:

[0016] A plurality of contrast values are determined according to the transmission light intensity, the temperature and the atmospheric pressure corresponding to each of the to-be-determined frequency points;

[0017] A plurality of candidate frequency points are determined based on the comparison result of the contrast values and the preset contrast threshold value.

[0018] Further, the process of determining 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 comprises:

[0019] A plurality of frequency deviation amounts are determined according to the absolute difference between the candidate frequency points and the preset ideal frequency;

[0020] inputting each of the frequency offset amounts into the preset radio frequency noise model to obtain a plurality of frequency stabilities;

[0021] determining a plurality of temporary frequency points based on a comparison result of the frequency stabilities and a preset stability threshold.

[0022] Further, the process of screening a plurality of concerned frequency points according to a time sequence variation feature of the transmitted light intensity of each of the temporary frequency points comprises:

[0023] obtaining a data sequence of the variation of the transmitted light intensity of each of the temporary frequency points over time within a preset screening period;

[0024] calculating a time sequence statistical feature of the data sequence to obtain the time sequence variation feature;

[0025] screening a plurality of the concerned frequency points from all of the temporary frequency points based on a comparison result of the time sequence variation feature and a preset time sequence variation threshold.

[0026] Further, the process of correcting all of the 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 comprises:

[0027] determining a plurality of temperature difference values according to the temperature of each of the concerned frequency points and the temperature of the next concerned frequency point adjacent thereto;

[0028] determining a plurality of temperature fluctuation values according to the temperature difference values within a preset correction period;

[0029] determining a plurality of the target frequency points based on a comparison result of the temperature fluctuation values and a preset temperature fluctuation threshold.

[0030] Further, the process of adjusting the preset C-field current value according to the target frequency points and a preset center frequency threshold comprises:

[0031] determining a plurality of target offset amounts according to an absolute difference between the target frequency points and a preset center frequency;

[0032] establishing a mapping relationship between the target offset amounts and C-field current variation based on a preset sensitivity model of C-field response to atomic transition energy level to obtain a plurality of C-field current correction values;

[0033] superimposing the C-field current correction values on the preset C-field current value to obtain an adjusted C-field current value.

[0034] Further, the process of adjusting the preset radio frequency power according to the time sequence variation features of the temperature and the air pressure comprises:

[0035] determining a plurality of temperature determination values according to the temperature from an initial time to each time within a preset power adjustment period;

[0036] determining a plurality of pressure determination values according to the air pressure at the initial time and each time within the preset power adjustment period;

[0037] adjusting the preset radio frequency power according to all the temperature determination values and all the pressure determination values.

[0038] Further, the process of adjusting the preset radio frequency power according to all the temperature determination values and all the pressure determination values comprises:

[0039] determining a change synchronization degree according to all the temperature determination values and all the pressure determination values;

[0040] adjusting the preset radio frequency power based on the comparison result of the change synchronization degree and a preset standard synchronization degree.

[0041] Further, the process of 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 the preset theoretical magnetic field comprises:

[0042] determining 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 as the radio frequency source output frequency.

[0043] On the other hand, the present application also provides a device for improving the efficiency of atomic coherent population trapping, comprising:

[0044] an encapsulation shell, which 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 integrating and protecting the internal components;

[0045] a Zennal coil, which is attached to the outer wall of the encapsulation shell 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;

[0046] a processing unit, which is arranged inside the encapsulation 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;

[0047] The collection module is used to collect the transmission light intensity corresponding to each to-be-determined frequency point, the temperature inside the radio frequency cavity and the air pressure of the environment 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 outdoor area.

[0048] 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;

[0049] 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;

[0050] The screening module 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.

[0051] The correction module is used for correcting all the 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.

[0052] The adjustment module is used for adjusting the preset C-field current value according to the target frequency point and the preset center frequency, and adjusting the preset radio frequency power according to the time sequence variation characteristics of the temperature and the air pressure based on the adjusted preset C-field current value.

[0053] The locking module is used for sequentially 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 an actual bias magnetic field value, and determining a 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.

[0054] Compared with the prior art, the beneficial effects of the present application are that by collecting multiple source physical parameters such as transmission light intensity, radio frequency cavity temperature and environmental air pressure in real time in a high-altitude outdoor area, a frequency point selection and adjustment mechanism is dynamically constructed, factors such as contrast threshold, frequency offset, radio frequency noise model and time sequence stability are comprehensively considered, target frequency points are selected step by step, and the actual bias magnetic field value is inversely deduced combined with the sensitivity model of the magnetic field change to the atomic transition frequency, 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 a complex and changeable outdoor environment, 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 coherence population and the trapping efficiency, and improving the overall performance and stability of the application system such as atomic frequency standard or quantum sensor.

[0055] Further, by coupling the local extreme value calculation of the transmission 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 point 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 effective suppression of misjudgment 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 realized in physics, and finally the physical accuracy and environmental adaptability of frequency point identification are improved, thereby providing more reliable foundation support for subsequent frequency point locking and magnetic field inversion.

[0056] Further, by introducing the deviation 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 spectral 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 combines the statistical characteristics of the frequency domain noise distribution, realizing the evaluation transformation from "optical response intensity" to "system stable operation ability". Through the quantitative processing of the mapping relationship between the frequency deviation and the noise model, the false frequency point response caused by the 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 screening are improved, providing a high confidence frequency point basis for subsequent frequency fine adjustment and magnetic field matching.

[0057] 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 affected by external disturbance or system noise can be effectively screened out, thereby retaining the frequency points with high signal stability and low volatility as the concerned frequency points. This screening mechanism reflects the close relationship between the dynamic change of the transmission light intensity and the time stability, and the frequency point stability is quantified using the statistical volatility 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.

[0058] 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 disturbance or local heating effect, ensuring that the finally 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 the frequency point selection and the long-term operation stability of the system as a whole.

[0059] Further, by converting the degree of 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 amount 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 integrates the behavior characteristics of multiple representative frequency points, thereby effectively reducing the influence of instantaneous interference on 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.

[0060] Further, by dynamically monitoring the change amplitude of temperature and air pressure within the preset power adjustment period, the standard deviation is calculated to obtain the temperature judgment value and the air pressure judgment value, and the preset radio frequency power is adaptively adjusted accordingly, which can realize fast response and compensation to external environmental disturbance. 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 statistical change trend can accurately reflect the potential influence of the current environmental state on system stability, so that the adjustment of radio frequency power is more targeted and adaptive, and the frequency scanning accuracy and resonance recognition efficiency of the system in complex environment are improved, and the stability of atomic signal transmission and detection sensitivity are guaranteed.

[0061] Further, by introducing the 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, 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.

[0062] Further, 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 the multi-target frequency point as the output, so that the radio frequency signal is more in line with the sensitive response condition of the atomic energy level to the 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 operating point changes.

[0063] Further, by integrating the packaging shell, the radio frequency cavity, the C-field coil, the Zeeman coil and the multi-functional processing unit, the system's automatic control and dynamic compensation capability is effectively improved while realizing compact structure and functional integration. Especially in high-altitude field environment, environmental parameters such as transmitted 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 operating point of atomic resonance, thereby improving the atomic coherent population efficiency and transition peak stability. Among them, through the linkage adjustment mechanism of temperature and air pressure on radio frequency power, the adaptability of the system to external disturbances is enhanced; through the mapping relationship between C-field current and frequency offset, a more refined feedback regulation channel is established; at the same time, combined with the dynamic correction method of temperature difference between target frequency points, it is helpful to identify the signal frequency point with more representative physical meaning, further improving the accuracy and robustness of frequency locking. Therefore, the device can significantly improve the frequency stability and magnetic field locking precision of the atomic system in complex environment, which is conducive to improving the overall performance level of quantum sensors, atomic clocks or atomic interference devices. BRIEF DESCRIPTION OF DRAWINGS

[0064] Figure 1 Flowchart of the implementation method for improving the atomic coherent population trapping efficiency of the present embodiment;

[0065] Figure 2 Determination logic diagram for determining a plurality of candidate frequency points of the present embodiment;

[0066] Figure 3 Determination logic diagram for determining a plurality of temporary frequency points of the present embodiment;

[0067] Figure 4 Structural schematic diagram of the device for improving the atomic coherent population trapping efficiency of the present embodiment. DETAILED DESCRIPTION

[0068] In order to make the objects and advantages of the present application clearer, the following further describes the present application with reference to the 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.

[0069] The preferred embodiments of the present application are 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.

[0070] Please refer to Figure 1 As shown in the flowchart of the implementation method for improving the atomic coherent population trapping efficiency, on the one hand, the present embodiment provides an implementation method for improving the atomic coherent population trapping efficiency, which comprises the following steps:

[0071] In the process of performing radio frequency sweeping in a high-altitude outdoor area with a preset C-field current value and a preset radio frequency power, 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;

[0072] According to the transmission light intensity, the temperature, the atmospheric pressure, and a preset contrast threshold, a plurality of candidate frequency points are determined;

[0073] According to each of the candidate frequency points, a preset ideal frequency, and a preset radio frequency noise model, a plurality of temporary frequency points are determined;

[0074] According to the time sequence variation characteristics of the transmission light intensity of each of the temporary frequency points, a plurality of concerned frequency points are screened out;

[0075] According to the temperature corresponding to each of any two adjacent concerned frequency points, all concerned frequency points are corrected to determine a plurality of target frequency points;

[0076] According to the target frequency points and a preset center frequency, the preset C-field current value is adjusted, and based on the adjusted preset C-field current value, according to the time sequence variation characteristics of the temperature and the atmospheric pressure, the preset radio frequency power is adjusted;

[0077] The radio frequency field is sequentially applied to each of the target frequency points 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 obtain the actual bias magnetic field value by inversion;

[0078] According to the matching degree of the actual bias magnetic field value of each target frequency point and a preset theoretical magnetic field, the output frequency of the radio frequency source is determined.

[0079] In this embodiment, when performing radio frequency sweeping in high-altitude outdoor areas, a photodetector integrated in the packaging shell is used to collect the transmitted light intensity through the 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 the 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 change inside the radio frequency cavity, and the environmental air pressure is measured by a miniature air pressure sensor (such as a MEMS air pressure gauge) installed on the outer wall of the shell. The output signals of the above-mentioned sensors are collected and recorded in real time by the acquisition module connected to the processing unit, ensuring that the light intensity, temperature, and air 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.

[0080] In this embodiment, the preset radio frequency noise model uses 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 training, a dataset containing 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 (such as the stability index based on phase noise and frequency jitter) corresponding to each frequency point 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.

[0081] 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.

[0082] The preset frequency step interval refers to the frequency difference between two adjacent scanning frequency points during radio frequency sweeping or radio frequency signal application. 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 650Hz and 750Hz. 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 1Hz, which can ensure measurement efficiency while accurately capturing the Zeeman transition resonance peak and improving the reliability of the inverted magnetic field value.

[0083] The preset action time parameter refers to the duration of applying the radio frequency signal to each frequency point, and 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, and a too short time may result in an unobvious resonance signal, and a too long time increases the measurement period. In the embodiment, the preset action time parameter is set to 2 ms, which can speed up the frequency point traversal speed on the premise of ensuring the sufficient response of the atomic system, thereby improving the overall detection efficiency.

[0084] The preset contrast threshold is a judgment standard for screening the light signal response intensity of the candidate frequency point, and depends on the sensitivity of the system to the change in the transmitted light intensity and the noise tolerance, and is usually set between 0.1 and 0.5 (unit: normalized contrast). In the embodiment, it is set to 0.25, which can effectively exclude the frequency points with large background light interference or unclear signal edges, and ensure that the selected frequency point has sufficient signal recognition degree and physical response reliability.

[0085] The preset ideal frequency is an ideal resonance frequency determined based on the atomic transition energy 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, the preset ideal frequency is set to 6.834682610 GHz in the embodiment, which can provide an accurate theoretical reference benchmark for frequency point screening and frequency stability evaluation.

[0086] The preset theoretical magnetic field is a reference magnetic field value for matching judgment with the actual bias magnetic field obtained by inversion, and depends on the C field coil design parameters, the driving current, and the atomic energy level Zeeman splitting model, and is usually set between 1 mG and 10 mG (mG is milligauss). In the 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 in the final frequency locking process, thereby improving the physical consistency and long-term stability of the frequency output.

[0087] 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 point selection and adjustment mechanism is dynamically constructed, and factors such as the contrast threshold, the frequency offset, the radio frequency noise model, and the timing stability are comprehensively considered, the target frequency point is selected step by step, and the actual bias magnetic field value is inversely deduced combined with the sensitivity model of the atomic transition frequency to the change in the magnetic field, and then the radio frequency source output frequency is optimized. This method can adaptively compensate for the disturbance to the system stability caused by temperature and air pressure in complex and variable outdoor 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 coherence population and the trapping efficiency, and improving the overall performance and stability of the application system such as the atomic frequency standard or the quantum sensor.

[0088] Please refer toFigure 2 As shown, it is a determination logic diagram for determining a plurality of candidate frequency points in the embodiment. In the embodiment, the process of determining a plurality of candidate frequency points according to the transmission light intensity, the temperature, the air pressure, and a preset contrast threshold value includes: determining a plurality of contrast values according to the transmission 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 a maximum value of the transmission light intensity in a preset local window, Imin is a minimum value of the transmission light intensity in the preset local window, ΔT is a difference value of the temperature and a preset temperature threshold value, ΔP is a difference value of the air pressure and a preset air pressure threshold value, α is a preset temperature adjustment coefficient, and β is a preset air pressure adjustment coefficient; and determining the to-be-determined frequency point as a candidate frequency point when the contrast value is greater than the preset contrast threshold value, so as to determine a plurality of candidate frequency points.

[0089] The preset local window refers to a set of frequency points in a fixed range extending forward and backward from the current to-be-determined frequency point in the spectrum scanning process, which depends on the system resolution, the frequency sampling accuracy, and the spectrum change trend. It is usually set in a range of ±2 to ±10 frequency points, and is set to ±5 frequency points in the embodiment, which can effectively capture the local transmission light intensity change, thereby improving the sensitivity and accuracy of the contrast value calculation.

[0090] The preset temperature threshold value refers to a reference temperature value for measuring the temperature deviation degree when the frequency point is collected, which depends on the system internal temperature control stability requirement and the sensitivity of atomic transition to thermal drift. It is usually set between 65°C and 90°C, and is set to 70°C in the embodiment, which can be used as an important benchmark for correcting the influence of temperature disturbance on contrast calculation, thereby improving the stability of frequency point determination.

[0091] The preset air pressure threshold value refers to a standard value for evaluating the air pressure change amplitude of the frequency point sampling under a specific altitude area, which depends on the average air pressure level of the measurement site and the tolerance of the system to air pressure change. It is usually set between 80 kPa and 100 kPa, and is set to 90 kPa in the embodiment, which can be used to compensate for the influence of air pressure change on light propagation characteristics and resonance stability, thereby ensuring the reliability of contrast determination.

[0092] The temperature adjustment coefficient is used to characterize the suppression strength of temperature change 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 design of the cavity stability, etc. It is usually set between 0.01 / °C and 0.2 / °C, and the larger the value, the more sensitive to temperature changes. In this embodiment, it is set to 0.05 / °C, which can appropriately suppress the 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.

[0093] The air pressure adjustment coefficient is used to describe the influence adjustment strength of environmental air pressure change on the contrast of transmitted light, which depends on the influence degree of external air pressure on the cavity sealing, the change of gas refractive index, 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.

[0094] 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 screening of candidate frequency points not only reflects the strength characteristics of optical response, but also 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 non-resonant frequency point misjudgment 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.

[0095] Please refer to Figure 3 As shown in FIG. 8, which is a determination logic diagram for determining a plurality of temporary frequency points in this embodiment. In this embodiment, the process of determining a plurality of temporary frequency points according to a plurality of candidate frequency points, a preset ideal frequency, and a preset radio frequency noise model includes: determining a plurality of frequency deviation amounts according to the absolute difference between the candidate frequency points and the preset ideal frequency; inputting each of the frequency deviation amounts into the preset radio frequency noise model to obtain a plurality of frequency stabilities; and determining a plurality of temporary frequency points based on the comparison result that the frequency stability is greater than a preset stability threshold.

[0096] The preset stability threshold is a reference parameter for determining whether the frequency deviation corresponds to stability in the radio frequency noise model meets the system requirements, depends on the phase noise characteristics of the frequency source, the tolerance of the system to frequency drift, and the line width characteristics of the target atomic transition, and 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 large noise influence, and ensure that the temporarily selected frequency points have higher frequency retention capability and signal consistency in actual operation.

[0097] By introducing the deviation 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 spectral 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 combines the statistical characteristics of the frequency domain noise distribution, realizing the evaluation transformation from "optical response strength" to "system stable operation ability". Through the quantitative processing of the mapping relationship between the frequency deviation and the noise model, false frequency point response 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 screening are improved, providing a high-confidence frequency point basis for subsequent frequency fine adjustment and magnetic field matching.

[0098] Specifically, the process of screening a plurality of attention frequency points according to the time sequence variation characteristics of the transmission light intensity of each temporary frequency point includes: obtaining the change data sequence of the transmission light intensity corresponding to each temporary frequency point over time within a preset screening period; calculating the standard deviation of the change data sequence after first-order difference processing, and combining the deviation mean of each data point in the preset sliding window to 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, the temporary frequency point is determined as an attention frequency point, to screen a plurality of attention frequency points.

[0099] The preset screening period refers to the total length of time for statistical analysis of the transmission light intensity variation of the temporary frequency point, and depends on the response time of the system to external disturbances and the evaluation needs of the frequency point stability, and is usually set between 200 ms and 2 s, and is set to 1 second in the embodiment, which 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.

[0100] The preset sliding window refers to the width of the continuous time period for local mean calculation within the screening period, and depends on the data sampling rate and the local fluctuation feature recognition requirement, and is usually set between 50 ms and 500 ms, and is set to 200 milliseconds in the embodiment, which can smooth the short-time peak noise while retaining the local dynamic information, and is helpful to accurately reflect the short-time stability of the frequency point.

[0101] The preset timing change threshold is a change characteristic numerical lower limit for determining whether the frequency point is stable, depends on the system noise level and the frequency point fluctuation tolerance, and is usually set between 0.01 and 0.1 (unit: normalized dimensionless value), and is set to 0.03 in the embodiment, can effectively eliminate the frequency points with large transmission light intensity fluctuations in a short time, and only keep the frequency points with stable response for subsequent inversion and regulation.

[0102] By performing first-order difference and sliding statistical processing on the transmission light intensity change data sequence of each temporary frequency point in the preset screening period, and comparing the obtained timing 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 high signal stability and low fluctuation as the concerned frequency points. This screening mechanism reflects the close relationship between the dynamic change of the transmission light intensity and the time stability, quantifies the frequency point stability by using the statistical fluctuation index, 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.

[0103] Specifically, 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: 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.

[0104] 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 value is less than a preset temperature fluctuation threshold, it is determined that the corresponding concerned frequency point is a target frequency point, to determine a plurality of target frequency points.

[0105] The preset correction period refers to the length of the time window for statistical temperature difference standard deviation in the concerned frequency point correction process, depends on the change rate of the environment temperature where the system is located and the temperature control response ability, and is usually set between 5s and 60s, and is set to 30s in the embodiment, 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 thermal stability identification precision of the target frequency point.

[0106] The preset temperature fluctuation threshold refers to the temperature difference standard deviation threshold for determining whether the adjacent concerned frequency points meet the thermal stability requirement, depends on the sensitivity requirement of the system to the frequency stability and the temperature measurement accuracy of the sensor, and is usually set between 0.01℃ and 0.1℃, and is set to 0.05℃ in the embodiment, which can effectively exclude unreliable frequency points caused by short-time temperature fluctuations, and enhance the environmental robustness of the finally locked frequency point.

[0107] By statistically analyzing the temperature difference between any adjacent target frequency points and calculating the standard deviation of the temperature difference value within a preset correction period, the degree of local temperature fluctuation between frequency points can be quantified. Further, by comparing the temperature fluctuation value with a 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 disturbance or local heating effect, ensuring that the finally 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 the frequency point selection and the long-term running stability of the system as a whole.

[0108] Specifically, 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 deviation amounts according to the absolute difference between the target frequency point and the preset center frequency, Δfi=∣fi-f0∣, where Δfi is the i-th target deviation amount, fi is the i-th target frequency point, and f0 is the preset center 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, a plurality of C-field current correction values are obtained, ΔIi=Δfi / S, where ΔIi is the i-th C-field current correction value, and S is the 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, 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.

[0109] The preset center 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. It is usually set between tens of hertz (Hz) and hundreds of hertz, and is set to 700 Hz in this embodiment, which can provide a stable physical reference for frequency point selection and ensure that the subsequent C-field regulation process is based on the core physical mechanism, improving the accuracy of resonance recognition and frequency locking.

[0110] 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, with a unit of megahertz per ampere (MHz / A), and depends on factors such as 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 uniformity of the magnetic field in the experimental environment. 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 this 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.

[0111] 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 approximately linear, that is, the change of transition frequency is proportional to the change of C field current within a certain range, and the proportional coefficient is the preset response sensitivity, which represents the change of atomic transition frequency 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.

[0112] 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.

[0113] Specifically, the process of adjusting the preset radio frequency power according to the time sequence variation 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.

[0114] The preset power adjustment period refers to the time window length of the system for statistical temperature and air pressure variation trend and adjustment of 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, the period 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 altitudes or fields in time, improving the consistency and resonance detection efficiency of the radio frequency signal.

[0115] 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 achieved. 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.

[0116] 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:

[0117] 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 of 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 × [1 + r × (P - P0) / P0], wherein U' is the increased preset radio frequency power, U is the preset radio frequency power before the increase, P is the change synchronization degree, P0 is the preset standard synchronization degree, and r is a preset synchronization degree adjustment coefficient.

[0118] 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.

[0119] 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 ability of the system under environmental disturbances.

[0120] 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 high synchronous 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.

[0121] 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:

[0122] Determining the target frequency corresponding to the minimum value of the difference between the actual bias magnetic field value and the preset theoretical magnetic field as the output frequency of the radio frequency source.

[0123] 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, the frequency point with the most consistent physical response can be accurately selected from multiple target frequency points as the output, making the radio frequency signal 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 changes in operating points.

[0124] 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:

[0125] 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 integrating and protecting the internal components;

[0126] 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;

[0127] 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.

[0128] The acquisition module is used to acquire the transmission light intensity corresponding to each candidate frequency point, the temperature inside the radio frequency cavity and the atmospheric pressure of the environment in real time during 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.

[0129] The candidate determination module is connected with the acquisition module and used to determine a plurality of temporary frequency points according to each candidate frequency point, a preset ideal frequency and a preset radio frequency noise model.

[0130] The temporary determination module is connected with the candidate determination module and used to determine a plurality of temporary frequency points according to the frequency offset of each candidate frequency point and the radio frequency noise model.

[0131] The screening module is connected with the temporary determination module and the acquisition module respectively and used to screen a plurality of concerned frequency points according to the time sequence variation characteristics of the transmission light intensity of each temporary frequency point.

[0132] The correction module is connected with the screening module and the acquisition module respectively and used to correct 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.

[0133] The adjustment module is connected with the correction module and the acquisition module respectively and used to adjust the preset C-field current value according to the target frequency point and a preset center frequency, and adjust the preset radio frequency power according to the time sequence variation characteristics of the temperature and the atmospheric pressure based on the adjusted preset C-field current value.

[0134] The locking module is connected with the correction module and used to apply a radio frequency field to each target frequency point re-determined after the preset radio frequency power is adjusted, measure the Zeeman transition resonance peak frequency of the target frequency point, obtain the actual bias magnetic field value by inversion, and determine 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.

[0135] 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. Among them, 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; 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 accuracy and the robustness of the frequency locking are further improved. Therefore, the device can significantly improve the frequency stability and the magnetic field locking accuracy of the atomic system in the complex environment, and is beneficial to improve the overall performance level of the quantum sensor, the atomic clock or the atomic interference equipment.

[0136] 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, comprising: The method comprises the following steps: real-time collection of transmission light intensity corresponding to each to-be-determined frequency point, temperature inside a radio frequency cavity, and atmospheric pressure of an environment during radio frequency sweep at a preset C-field current value and a preset radio frequency power in a high-altitude field area; determination of a plurality of candidate frequency points according to the transmission light intensity, the temperature, the atmospheric pressure, and a preset contrast threshold value; determination of 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; screening of a plurality of concerned frequency points according to time sequence variation characteristics of the transmission light intensity of each of the temporary frequency points; correction of all the 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; adjustment of the preset C-field current value according to the target frequency points and a preset center frequency, and adjustment of the preset radio frequency power based on the adjusted preset C-field current value according to time sequence variation characteristics of the temperature and the atmospheric pressure; successive application of a radio frequency field to each of the target frequency points re-determined after the preset radio frequency power is adjusted, and measurement of Zeeman transition resonance peak frequency of the target frequency points to inversely obtain an actual bias magnetic field value; determination of a radio frequency source output frequency according to a matching degree of the actual bias magnetic field value of each target frequency point and a preset theoretical magnetic field; the process of determining 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 comprises: determination of a plurality of frequency deviation amounts according to absolute difference values of the candidate frequency points and the preset ideal frequency; input of each of the frequency deviation amounts into the preset radio frequency noise model to obtain a plurality of frequency stabilities; determination of a plurality of temporary frequency points based on a comparison result of the frequency stabilities and a preset stability threshold value; the process of correcting all the 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 comprises: determination of a plurality of temperature difference values according to the temperature of each of the concerned frequency points and the temperature of the next concerned frequency point adjacent thereto; determination of a plurality of temperature fluctuation values according to the temperature difference values within a preset correction period; determination of a plurality of the target frequency points based on a comparison result of the temperature fluctuation values and a preset temperature fluctuation threshold value; the process of adjusting the preset C-field current value according to the target frequency points and a preset center frequency threshold value comprises: determination of a plurality of target deviation amounts according to absolute difference values of the target frequency points and a preset center frequency; establishment of a mapping relationship between the target deviation amounts and C-field current changes based on a preset sensitivity model of C-field response to atomic transition energy level to obtain a plurality of C-field current correction values; superposition of the C-field current correction values on the preset C-field current value to obtain an adjusted C-field current value.

2. The implementation 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 transmission light intensity, the temperature, the atmospheric pressure, and a preset contrast threshold value comprises: determination of a plurality of contrast values according to the transmission light intensity, the temperature, and the atmospheric pressure corresponding to each of the to-be-determined frequency points; determination of a plurality of the candidate frequency points based on a comparison result of the contrast values and the preset contrast threshold value.

3. The method of claim 2, wherein the method comprises: the process of screening a plurality of concerned frequency points according to time sequence variation characteristics of the transmission light intensity of each of the temporary frequency points comprises: Obtaining the change data sequence of the transmission light intensity corresponding to each temporary frequency point in a preset screening period over time; Calculating the time sequence statistical characteristics of the change data sequence to obtain the time sequence change characteristics; Based on the comparison result of the time sequence change characteristics and the preset time sequence change threshold, a plurality of concerned frequency points are screened out from all the temporary frequency points.

4. The implementation method for improving atomic coherent population trapping efficiency according to claim 3, characterized in that, The process of adjusting the preset radio frequency power according to the time sequence change characteristics of the temperature and the air pressure includes: Determining a plurality of temperature judgment values according to the temperature at the initial time and at each time within a preset power adjustment period; Determining a plurality of air pressure judgment values according to the air pressure at the initial time and at each time within the preset power adjustment period; Adjusting the preset radio frequency power according to all the temperature judgment values and all the air pressure judgment values.

5. The method of claim 4, wherein the method comprises: 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 the change synchronization degree according to all the temperature judgment values and all the air pressure judgment values; Adjusting the preset radio frequency power based on the comparison result of the change synchronization degree and the preset standard synchronization degree.

6. The implementation method for improving atomic coherent population trapping efficiency according to claim 5, characterized in that, 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 includes: Determining the output frequency of the radio frequency source as 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.

7. An apparatus for improving the efficiency of atomic coherent population trapping, constructed on the basis of the method for improving the efficiency of atomic coherent population trapping according to any one of claims 1 to 6, characterized in that, It includes: A packaging shell, which is internally 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 Zener coil attached to the outer wall of the packaging shell, with its magnetic field direction perpendicular to that of the C-field coil, for applying a radio frequency field; A processing unit arranged inside the packaging shell, including 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 corresponding to each to-be-determined frequency point, the temperature inside the radio frequency cavity, and the air 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; The candidate determination module is used to determine 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 used to determine 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 used to screen a plurality of concerned frequency points according to the time sequence change characteristics of the transmission light intensity of each temporary frequency point; The correction module is used to correct 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; The adjustment module is used to adjust the preset C-field current value according to the target frequency point and the 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 air pressure; The locking module is used to sequentially apply a radio frequency field to each of the target frequency points re-determined after the preset radio frequency power is adjusted, and measure the Zeeman transition resonance peak frequency of the target frequency point to inversely obtain an actual bias magnetic field value, and 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.

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