CN-122017374-A - Closed loop locking detection method and system based on AT split signals of Redberg atoms

CN122017374ACN 122017374 ACN122017374 ACN 122017374ACN-122017374-A

Abstract

The application relates to the technical field of quantum precision measurement and automatic control, and discloses a closed-loop lock detection method and system based on a Redberg atom AT split signal. The method comprises the steps of obtaining EIT signals under the condition of no microwave field, locking the frequency of coupled laser AT a preset reference point to establish a frequency reference, enabling the coupled laser and detected laser to pass through an air chamber in a collinear mode after being combined, controlling the frequency of the coupled laser to be switched among preset target frequency points by a laser frequency shifter when an AT splitting is generated by applying a microwave field to be detected to the air chamber, carrying out phase-sensitive detection on transmission intensity signals of a detected laser light path by using a lock-in amplifier, generating error voltage signals based on the AT splitting signals, locking error voltage zero crossing points corresponding to two AT splitting peaks by a servo controller, and calculating the intensity of a microwave electric field to be detected according to a feedback control quantity difference value of the locking points. The application improves the measurement precision, enhances the anti-interference capability, improves the working stability and realizes the rapid and stable detection of the microwave electric field.

Inventors

XUE HONGBO
MA MUFU
SONG WEI
YANG ANQI
Ren Chenmo
WANG JINDONG
SHI JUN

Assignees

中国科学院国家空间科学中心

Dates

Publication Date: 20260512
Application Date: 20260415

Claims (7)

1. A closed loop lock detection method based on a Redberg atom AT split signal comprises the following steps: Acquiring an electromagnetic induction transparent EIT signal under the condition of no microwave field, and locking the frequency of the coupled laser output by the coupled laser at a preset reference point to establish a frequency reference; the coupled laser and the detection laser emitted by the detection laser are combined and then pass through the air chamber in a collinear way, and a microwave field to be detected is applied; when a microwave field to be detected is applied to the air chamber to enable the atomic energy level to generate AT splitting, the frequency of the coupled laser is controlled to be switched between two preset target frequency points through a laser frequency shifter; Phase-sensitive detection is carried out on a transmission intensity signal of a detection laser light path by using a phase-locked amplifier, an error voltage signal is generated based on an AT split signal, and the error voltage signal is fed back to a servo controller; Outputting control signals through the servo controller, respectively locking the system AT error voltage zero crossing points corresponding to two AT split peaks, and recording and maintaining feedback control amounts of the two locking points; And calculating the intensity of the microwave electric field to be detected according to the difference value of the feedback control amounts of the two locking points.
2. The AT split signal closed loop lock detection method according to claim 1, wherein the preset reference point is a frequency position corresponding to a peak value of an electromagnetic induction transparent EIT signal under a microwave field-free condition.
3. The AT split signal closed loop lock detection method of claim 1, wherein the laser frequency shifter is driven by a sine wave generated by a driver.
4. The AT split signal closed loop lock detection method according to claim 1, wherein the preset target frequency point is a frequency position corresponding to a peak value of two AT split signals.
5. The AT split signal closed loop lock detection method of claim 1, wherein the error voltage signal is zero crossing AT a frequency location of a peak of the AT split signal and has a voltage-frequency slope near the zero crossing.
6. The AT split signal closed loop lock detection method of claim 1, wherein the servo controller is a digital PID servo controller.
7. A closed loop lock detection system based on a reed-burg atom AT split signal for performing the method of any of claims 1-6, comprising: The laser comprises a detection light laser and a coupling light laser, wherein the detection light laser and the coupling light laser are used for emitting detection laser and coupling laser; The laser frequency shifter is arranged on the light path of the coupling laser and is used for locking the frequency of the coupling laser emitted by the coupling laser AT a preset reference point to establish a frequency reference, and after the AT splitting is generated by applying the microwave field to be detected, the frequency of the coupling laser is controlled to be switched between preset target frequency points through the laser frequency shifter; A microwave antenna for applying a microwave field to the gas chamber; A dichroic mirror including a first dichroic mirror and a second dichroic mirror for combining the detection laser light and the coupled laser light and passing through the gas cell; A gas cell for containing a Redberg atom; the photoelectric detector is used for receiving the detection laser after passing through the air chamber and outputting photoelectric signals; the input signal selection module is connected with the photoelectric detector and is used for inputting photoelectric signals to the two phase-locked amplifiers; the two phase-locked amplifiers are used for respectively carrying out phase-sensitive detection on the transmission intensity signals of the detection laser light path and generating corresponding error signals; the two servo controllers are respectively connected with the two phase-locked amplifiers and are used for generating control signals according to the corresponding error signals; The two frequency source modules are respectively connected with the two servo controllers and used for outputting driving signals with adjustable frequency under the control of the corresponding servo controllers; the output signal selection module is connected with the two frequency source modules and is used for selecting one path of driving signals and outputting the driving signals to the driver; the driver is connected with the laser frequency shifter and is used for generating a sine wave signal to drive the laser frequency shifter; an electric field strength calculating module for calculating the electric field strength of the microwave to be measured according to the control amounts of the two locking points, and And the central controller is used for coordinating the system to work and calculating the intensity of the microwave electric field.

Description

Closed loop locking detection method and system based on AT split signals of Redberg atoms Technical Field The application relates to the technical field of quantum precision measurement and automatic control, in particular to a closed-loop locking detection method and system based on a Redberg atom AT split signal. Background The Redberg atoms have extremely high sensitivity to microwave electric fields due to the huge electric dipole moment, so that the electric field measurement technology based on the Electromagnetic Induction Transparency (EIT) and Autler-Townes (AT) splitting effect of the Redberg atoms becomes a front hot spot in the field of quantum precision measurement. Autler-Townes (AT) splitting refers to the phenomenon that atoms split energy levels under the action of a strong resonant electromagnetic field. However, accurate detection and stable locking of the AT split signal has been a technical difficulty. The current mainstream methods include: The manual scanning method is characterized in that the frequency of the coupled laser is manually adjusted, the whole AT splitting spectrum is slowly scanned, the frequency difference (splitting) is calculated after the positions of two peaks are recorded, the method is low in efficiency, real-time measurement cannot be realized, the method is seriously dependent on the experience of operators, personal errors are easy to introduce, and the repeatability is poor. The automatic peak locking method is to directly lock the peak value of the AT split signal by adopting an analog circuit or a software algorithm. Although automation is achieved, the method has inherent defects that firstly, the signal-to-noise ratio is poor, the amplitude of a direct locking signal is very sensitive to the intensity noise of a laser, the low-frequency drift of a light beam and other amplitude noise, secondly, the locking precision is low, the derivative (namely the slope) of the signal intensity to the frequency change is close to zero near the peak point of a spectrum, the locking point is fuzzy, the sensitivity and the precision of frequency tracking are limited, and finally, the stability is poor, and any factor causing the fluctuation of the light intensity can be directly converted into the drift of the frequency locking point. The method is characterized in that the amplitude modulation is carried out on a microwave field to be detected to obtain a dispersion signal of EIT-AT spectrum on the frequency of detection light, two zero crossing points appear on the dispersion signal AT the moment, and the intensity of the microwave field can be obtained by measuring the distance between the zero crossing points of the dispersion signal, but the method only scans and does not realize closed-loop locking on AT split signals. Therefore, a method is needed to meet the real-time dynamic measurement requirements of high precision, high speed and high anti-interference capability on the microwave electric field. Disclosure of Invention The application aims to overcome the defect that the prior art is difficult to meet the real-time dynamic measurement requirement of high precision, high speed and high anti-interference capability on a microwave electric field, and further provides a closed-loop locking detection method and system based on a Redberg atom AT split signal, which have high measurement precision, high response speed and high anti-interference capability. In order to solve the technical problems, the technical scheme of the application provides a closed loop lock detection method based on a Redberg atom AT split signal, which comprises the following steps: Acquiring an electromagnetic induction transparent EIT signal under the condition of no microwave field, and locking the frequency of the coupled laser output by the coupled laser at a preset reference point to establish a frequency reference; the coupled laser and the detection laser emitted by the detection laser are combined and then pass through the air chamber in a collinear way, and a microwave field to be detected is applied; when a microwave field to be detected is applied to the air chamber to enable the atomic energy level to generate AT splitting, the frequency of the coupled laser is controlled to be switched between two preset target frequency points through a laser frequency shifter; Phase-sensitive detection is carried out on a transmission intensity signal of a detection laser light path by using a phase-locked amplifier, an error voltage signal is generated based on an AT split signal, and the error voltage signal is fed back to a servo controller; Outputting control signals through the servo controller, respectively locking the system AT error voltage zero crossing points corresponding to two AT split peaks, and recording and maintaining feedback control amounts of the two locking points; And calculating the intensity of the microwave electric field to be detected according to the difference valu