CN-121978399-A - Broadband measurement system and method based on Redburg atoms

CN121978399ACN 121978399 ACN121978399 ACN 121978399ACN-121978399-A

Abstract

The invention relates to a broadband measurement system and method based on a Redberg atom, and belongs to the technical field of spectrum measurement. The system of the invention continuously collects the frequency spectrum of the obtained intermediate frequency signal by scanning the frequency of the local oscillator field applied to the atomic air chamber, finally splices to obtain the broadband frequency spectrum information, solves the technical problem existing in the optical frequency comb mode locking process, and can realize the electromagnetic spectrum monitoring of the cross-multi-frequency broadband. The invention can measure electromagnetic spectrum through the Redberg probe. The microstrip line structure can generate a stronger electric field on the surface and has small volume, so that the microstrip line structure is combined with the atomic probe to form the integrated atomic probe. Therefore, the heterodyne method is utilized to expand the measuring range of the Redberg atoms from a resonance point to a non-resonance point, and the optimal sensitivity is-100 dBm/Hz.

Inventors

ZHAO PENGJU
MIAO YINXIAO
ZHANG TIELI
GE MENG
HU HUIJIE
WANG ZONGJUN
LIU HAO
ZHANG YONGCHAO

Assignees

北京航天计量测试技术研究所

Dates

Publication Date: 20260505
Application Date: 20251120

Claims (10)

1. A broadband measurement system based on a Redberg atom is characterized by comprising a coupling light laser, a detection light laser, a photoelectric detector, a local oscillation signal source, an atomic probe and a frequency spectrograph, wherein the atomic probe is integrated with an atomic air chamber and a microstrip line structure, the atomic air chamber is filled with atomic steam, the microstrip line structure is used for transmitting microwaves and generating a local electric field on the surface, the coupling light laser is used for generating coupling light, the detection light laser is used for generating detection light, the coupling light and the detection light coincide in the atomic air chamber to excite atoms to a Redberg state, the local oscillation signal source is used for generating a local oscillation field and acts on the atoms in the atomic air chamber through the microstrip line structure, the photoelectric detector is used for detecting a detection light signal passing through the atomic air chamber and converting the detection light signal into an electric signal to be sent to the frequency spectrograph, and the frequency spectrograph is used for measuring the frequency spectrum of the electric signal, wherein the frequency of the detection light signal is scanned and the corresponding intermediate frequency spectrum is acquired, and the broadband electromagnetic spectrum is obtained through splicing.
2. The system of claim 1, wherein the local oscillator signal source is frequency tunable and the intermediate frequency signal collected by the spectrometer during the local oscillator frequency sweep is in a frequency range between 50kHz and 150 kHz.
3. The system according to claim 1 or 2, wherein the system is configured to optimize the intensity of the local oscillator field before measuring, in particular to output the local oscillator field and the signal field to the microstrip line structure simultaneously, keep the frequency difference between them at a fixed intermediate frequency, adjust the intensity of the local oscillator field such that the intermediate frequency signal intensity is maximized, and save the correspondence between the local oscillator frequency and the optimal local oscillator field intensity.
4. The system of claim 1, wherein the microstrip line structure is a microstrip line integrated on an atomic probe for generating a localized microwave electric field at a surface of the atomic gas cell to enhance electric field strength and form a compact structure with the atomic probe.
5. A broadband measurement method based on a Redburg atom is characterized by adopting the system as claimed in any one of claims 1 to 4, and comprises the following steps of locking detection light on resonance frequencies of an atomic ground state and an excited state, locking coupling light on an electromagnetic induction transparent peak so as to excite the atom to the Redburg state, optimizing local field intensity, namely outputting the local field and a signal field to a microstrip line structure at the same time, keeping the frequency difference between the local field and the signal field at a fixed intermediate frequency, adjusting the intensity of the local field to enable the intermediate frequency signal intensity to be maximum, optimizing the size of the local field point by point in a measurement frequency band, and storing the corresponding relation between the local frequency and the optimal local field intensity, fixing one local frequency during measurement, collecting the intermediate frequency spectrum of a spectrometer, continuously changing the local frequency, repeating the step three, collecting intermediate frequency spectrums corresponding to a plurality of local frequencies, and splicing all collected intermediate frequency spectrums to obtain a broadband electromagnetic wave spectrum.
6. The method of claim 5, wherein in the fourth step, the local oscillation frequency is changed in a frequency hopping manner to avoid low-frequency noise of the photodetector, the frequency hopping manner is specifically that the local oscillation frequency is changed from an initial state according to a predetermined sequence, and the intermediate frequency signal acquired after each change covers a frequency spectrum part with a frequency greater than or less than the local oscillation frequency.
7. The method according to claim 5 or 6, wherein the fixed intermediate frequency is 100kHz and the acquisition range of the intermediate frequency spectrum is 50kHz to 150kHz.
8. The method of claim 5, wherein the broadband electromagnetic spectrum coverage ranges from 0.2GHz to 40GHz, and the scan time is on the order of 10 seconds per GHz.
9. The method according to claim 5, wherein in the second step, the optimization of the local field strength so that the intermediate frequency signal strength is maximized is based on an intrinsic gain coefficient of the atomic superheterodyne measurement model, the intrinsic gain coefficient being affected by the local field strength and having an optimal value.
10. The method of claim 5, wherein the method is adapted for non-resonant point measurement, and wherein the high frequency microwave signal is down-converted to an intermediate frequency signal by heterodyning to achieve electromagnetic spectrum monitoring across multiple frequency ranges.

Description

Broadband measurement system and method based on Redburg atoms Technical Field The invention relates to a broadband measurement system and method based on a Redberg atom, and belongs to the technical field of spectrum measurement. Background Electric field measurement based on the reed-burg atoms is the leading direction in the field of quantum precision measurement in recent years. Because of the characteristic of great polarization rate of the Redberg atoms and very sensitive to an external electric field, the Redberg atomic polarization detector has been widely studied in the application fields of electric field intensity measurement, communication reception and the like. In particular, in the field of spectrum monitoring, it is difficult for a conventional radio receiver based on a metal antenna to measure signals of a plurality of frequency ranges at the same time due to structural limitations. The Redberg atoms can receive microwave electric fields across multiple frequency ranges due to the rich energy level structure. However, the current problem is that the instantaneous bandwidth of receiving the reed-burg atoms is narrow, and breakthroughs based on the spectrum monitoring of the reed-burg atoms are needed. Disclosure of Invention In view of the foregoing, the present invention provides a system and method for wideband measurement based on the reed-burg atom, which can implement electromagnetic spectrum monitoring across multiple frequency bands. In order to achieve the purpose of the invention, the following technical scheme is provided. A broadband measurement system based on a Redberg atom comprises a coupling light laser, a detection light laser, a photoelectric detector, a local oscillation signal source, an atomic probe and a spectrometer, wherein the atomic probe is integrated with an atomic air chamber and a microstrip line structure, the atomic air chamber is filled with atomic steam, the microstrip line structure is used for transmitting microwaves and generating a local electric field on the surface, the coupling light laser is used for generating coupling light, the detection light laser is used for generating detection light, the coupling light and the detection light coincide in the atomic air chamber to excite atoms to a Redberg state, the local oscillation signal source is used for generating a local oscillation field and acts on the atoms in the atomic air chamber through the microstrip line structure, the photoelectric detector is used for detecting the detection light signal after passing through the atomic air chamber and converting the detection light signal into an electric signal to be sent to the spectrometer, and the spectrometer is used for measuring the frequency spectrum of the electric signal, wherein the frequency of the local oscillation signal is scanned, the corresponding intermediate frequency spectrum is acquired, and the broadband electromagnetic spectrum is obtained through splicing. 2. The frequency of the local oscillation signal source is adjustable, and in the process of local oscillation frequency scanning, the frequency range of the intermediate frequency signal acquired by the frequency spectrograph is between 50kHz and 150 kHz. The system is configured to optimize the intensity of the local oscillator field before measurement, specifically, the local oscillator field and the signal field are simultaneously output to the microstrip line structure, the frequency difference between the local oscillator field and the signal field is kept at a fixed intermediate frequency, the intensity of the local oscillator field is adjusted to enable the intensity of the intermediate frequency signal to be maximum, and the corresponding relation between the local oscillator frequency and the optimal local oscillator field intensity is saved. The microstrip line structure is a microstrip line integrated on the atomic probe and is used for generating a local microwave electric field on the surface of the atomic gas chamber so as to enhance the electric field intensity and form a compact structure with the atomic probe. The invention also provides a broadband measurement method based on the Redberg atoms, which comprises the following steps of locking detection light on resonance frequencies of an atomic ground state and an excited state, locking coupling light on an electromagnetic induction transparent peak so as to excite atoms to the Redberg state, optimizing local oscillator field strength, namely, simultaneously outputting the local oscillator field and a signal field to a microstrip line structure, keeping the frequency difference between the local oscillator field and the signal field at a fixed intermediate frequency, adjusting the strength of the local oscillator field to enable the intermediate frequency signal strength to be maximum, optimizing the size of the local oscillator field point by point in a measurement frequency band, storing the corresponding relati