CN-122016073-A - In-situ measurement system and method for temperature sensitivity in optical frequency standard

CN122016073ACN 122016073 ACN122016073 ACN 122016073ACN-122016073-A

Abstract

The application discloses an in-situ measurement system and method for temperature sensitivity in an optical frequency standard, and relates to the technical field of quantum precision measurement and optical frequency standard. The device comprises a quantum trapping device, a radiation field modulation subsystem, an optical detection subsystem and a comprehensive control and demodulation unit, wherein the quantum trapping device is arranged in a vacuum system and comprises a quantum probe, a light absorber and a temperature measurement module, the radiation field modulation subsystem comprises a mid-infrared laser, a light intensity modulator and a light path guiding system, and the optical detection subsystem comprises an ultra-stable Zhong Jiguang device, a fluorescence collection and detection module and a frequency measurement module. The method is used for solving the technical problem of in-situ and direct measurement of response sensitivity of transition frequency to temperature at an atom/ion trapping position.

Inventors

Shang Haosen
LIN ZAISHENG
XUE XIAOBO
ZHANG SHENGKANG
GE JUN

Assignees

北京无线电计量测试研究所

Dates

Publication Date: 20260512
Application Date: 20251225

Claims (10)

1. The in-situ measurement system for temperature sensitivity in the optical frequency standard is characterized by comprising a quantum trapping device, a radiation field modulation subsystem, an optical detection subsystem and a comprehensive control and demodulation unit, wherein the quantum trapping device, the radiation field modulation subsystem, the optical detection subsystem and the comprehensive control and demodulation unit are arranged in a vacuum system, and the in-situ measurement system is characterized in that: the quantum trapping device comprises a quantum probe, a light absorber and a temperature measuring module, the radiation field modulation subsystem comprises a mid-infrared laser, a light intensity modulator and a light path guiding system, and the optical detection subsystem comprises an ultra-stable Zhong Jiguang device, a fluorescence collection and detection module and a frequency measuring module; The intermediate infrared laser is sequentially connected with a light intensity modulator and a light path guiding system, and the light path guiding system guides the modulated intermediate infrared laser to a specific area of the quantum trapping device; The temperature measuring module is integrated on or close to the light absorber and is used for monitoring temperature fluctuation of the light absorber caused by middle infrared laser modulation in real time and in situ and inputting temperature data to the comprehensive control and demodulation unit; The output beam of the ultra-stable Zhong Jiguang device acts on the quantum probe; the fluorescence collection and detection module is used for collecting fluorescence generated by the quantum probe, converting the fluorescence into an electric signal and inputting the electric signal to the comprehensive control and demodulation unit; the frequency measurement module is used for measuring the frequency of the ultra-stable Zhong Jiguang device and inputting frequency data to the comprehensive control and demodulation unit; The modulation signal output end of the integrated control and demodulation unit is connected to the light intensity modulator and is used for generating a modulation signal to drive the light intensity modulator, taking the modulation signal as a reference, carrying out digital phase-sensitive demodulation on the frequency data of the frequency measurement module and the temperature data of the temperature measurement module, and resolving the frequency-temperature sensitivity at the current system reference temperature.
2. The system of claim 1, wherein the quantum trapping device is configured to stably trap single or multiple atoms or ions using a magneto-optical trap, a linear ion trap, a toroidal ion trap, an end cap ion trap, or a chip ion trap.
3. The system of claim 1, wherein the light absorber is made of silicon nitride, doped silicon, or graphene.
4. The system of claim 1, wherein the light absorber is configured as a suspended microbridge, thermal isolation film, or back side absorber layer of a chip fabricated by a micro-nano process.
5. The system of claim 1, wherein the temperature measurement module employs a micro-resistance temperature detector, thermistor or thermocouple sized and material compatible with the ultra-high vacuum and electrical environment of the quantum confinement device, and a signal output connected to the integrated control and demodulation unit through a vacuum electrical feedthrough.
6. The system of claim 1, wherein the optical path directing system employs vacuum compatible mid-infrared optical fibers and fiber optic feedthroughs.
7. The system of claim 1, wherein the ultra-stable Zhong Jiguang employs a narrow linewidth laser whose frequency is locked onto the narrow linewidth Zhong Yue transition of the quantum probe.
8. The system of claim 1, wherein the fluorescence collection and detection module comprises a high numerical aperture objective, a spectral filter, and a photodetector employing a photomultiplier tube for quantum-hopping detection of a single quantum probe or employing an electron-multiplying charge-coupled device camera for spatially resolved imaging of a quantum probe ensemble.
9. The system of claim 1, wherein the frequency measurement module employs an optical frequency comb for comparing the optical frequency of the ultra-stable Zhong Jiguang with other frequency standards to achieve accurate measurement of absolute frequency.
10. A method of using the temperature-sensitive in-situ measurement system of any of claims 1-9, comprising: S1, starting a vacuum system, a quantum trapping device and an optical detection subsystem, stably trapping and laser cooling a quantum probe in the quantum trapping device, locking the frequency of an ultra-stable Zhong Jiguang device in the optical detection subsystem on a clock transition spectrum line of the quantum probe, and continuously measuring the frequency of the Zhong Jiguang device by utilizing a frequency measuring module; S2, generating a periodic modulation signal with the frequency omega by the comprehensive control and demodulation unit, inputting the modulation signal to a light intensity modulator of the radiation field modulation subsystem, and periodically modulating the light intensity of the intermediate infrared laser to ensure that the temperature of the light absorber and the local effective temperature T eff of the quantum probe generate periodic fluctuation with the same frequency; s3, inputting the frequency signal of the Zhong Jiguang device and the temperature signal from the temperature measurement module which are continuously measured into the comprehensive control and demodulation unit at the same time, and respectively carrying out digital phase-sensitive demodulation on the frequency signal and the temperature signal of the Zhong Jiguang device by taking the periodic modulation signal as a reference signal to obtain a demodulation result; S4, according to the demodulation result, respectively calculating the amplitude delta v of clock transition frequency fluctuation and the amplitude delta T of light absorption body temperature fluctuation at the modulation frequency omega, and obtaining the frequency-temperature sensitivity at the current system reference temperature by calculating the response ratio S=delta v/delta T.

Description

In-situ measurement system and method for temperature sensitivity in optical frequency standard Technical Field The application relates to the technical field of quantum precision measurement and optical frequency standard, in particular to an in-situ measurement system and method for temperature sensitivity in an optical frequency standard. Background The optical frequency standard, especially the caged ion optical clock and the neutral atomic optical lattice clock, is the most accurate physical measuring device at present, the uncertainty of the device is 10 -18 orders of magnitude, and the device has great application value in the fields of basic physical research (such as checking basic physical constants, detecting dark substances), relativistic geometrics, next-generation time keeping, navigation positioning and the like. With the increasing precision of optical clocks, zhong Yueqian frequency stark shift caused by ambient thermal radiation (i.e., blackbody radiation, BBR) has become one of the major bottlenecks limiting the total uncertainty. The magnitude of the BBR frequency shift is proportional to the fourth power of the effective temperature of the environment in which the atoms are located. In the traditional BBR frequency shift calibration method, a plurality of temperature sensors are usually arranged on the cavity wall of a vacuum system, and the effective temperature of the position of atoms/ions is indirectly calculated by measuring the temperature of the cavity wall and combining a complex heat conduction model filled with uncertainty. The ex-situ calculation method has two fundamental defects that firstly, a significant thermal gradient exists in a vacuum system, particularly in devices with complex structures such as an ion trap and the like, a laser window, an electrical feed-through, a supporting structure and the like can become a heat source or a cold source, so that the difference between the effective temperature and the cavity wall temperature is difficult to model accurately, secondly, laser used for trapping and detecting atoms/ions is inevitably absorbed by nearby structures, a dynamic and local laser heating effect is generated, and the effect cannot be perceived accurately by a remote thermometer. The evaluation caused by these factors together is subject to great uncertainty, severely limiting the final accuracy of the optical clock. Therefore, developing a device that can measure the response sensitivity of transition frequency to temperature in situ and directly at the atomic/ion trapping site is a key technical problem to be solved in the art. Disclosure of Invention The application aims to provide an in-situ measurement system and method for temperature sensitivity in an optical frequency standard, which are used for solving the technical problem of in-situ and direct measurement of response sensitivity of transition frequency to temperature at an atomic/ion trapping position. In order to achieve the above purpose, the application adopts the following technical scheme: in one aspect, the application provides an in-situ measurement system for temperature sensitivity in an optical frequency standard, comprising a quantum trapping device, a radiation field modulation subsystem, an optical detection subsystem and a comprehensive control and demodulation unit, wherein the quantum trapping device, the radiation field modulation subsystem, the optical detection subsystem and the comprehensive control and demodulation unit are arranged in a vacuum system, and the in-situ measurement system comprises: the quantum trapping device comprises a quantum probe, a light absorber and a temperature measuring module, the radiation field modulation subsystem comprises a mid-infrared laser, a light intensity modulator and a light path guiding system, and the optical detection subsystem comprises an ultra-stable Zhong Jiguang device, a fluorescence collection and detection module and a frequency measuring module; The intermediate infrared laser is sequentially connected with a light intensity modulator and a light path guiding system, and the light path guiding system guides the modulated intermediate infrared laser to a specific area of the quantum trapping device; The temperature measuring module is integrated on or close to the light absorber and is used for monitoring temperature fluctuation of the light absorber caused by middle infrared laser modulation in real time and in situ and inputting temperature data to the comprehensive control and demodulation unit; The output beam of the ultra-stable Zhong Jiguang device acts on the quantum probe; the fluorescence collection and detection module is used for collecting fluorescence generated by the quantum probe, converting the fluorescence into an electric signal and inputting the electric signal to the comprehensive control and demodulation unit; the frequency measurement module is used for measuring the frequency of the ultra-stable Zhong