Table of Content

15 October 2024, Volume 44 Issue 5

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Faraday Lasers for Quantum Metrology Applications

ZHANG Jia, SHI Hangbo, WANG Zhiyang, QIN Xiaomin, LIU Zijie, GUAN Xiaolei, GAO Xun, WANG Yu, SHI Tiantian, CHEN Jingbiao

2024, 44(5):  1-7.  doi:10.12060/j.issn.1000-7202.2024.05.01

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High-precision frequency-stabilized lasers are an important foundation and component for realizing the realization of quantum precision measurement.Faraday laser utilizes atomic filter for frequency selection,and the output wavelength is limited to the transmission spectrum near the atomic transition frequency,which has significant advantages such as automatic correspondence between wavelength and atomic spectral line,narrow linewidth,and resistance to laser diode current and temperature fluctuations.Faraday lasers have many applications in the field of quantum metrology,such as atomic clocks,atomic gravimeters,and atomic magnetometers.Starting from the research background and basic principle of Faraday lasers,we introduce the practical applications and important values of Faraday lasers in such fields as cesium atomic clock,atomic gravimeter,and optical communication are introduced.In the future,with the continuous maturity and innovation,Faraday lasers are expected to realize a wide range of applications in more fields,such as high-power laser weapons,Reedburg atomic radar,etc.,which are expected to play a greater role in the field of national defense and military industry measurement.

The Research Advancements and Trends in Chip-integrated Metrology within the Framework of the New International System of Units (SI)

GUO Linbao, ZHAO Zhao, LI Daozheng, LI Yajie, SHA Changtao, ZHANG Hong

2024, 44(5):  8-15.  doi:10.12060/j.issn.1000-7202.2024.05.02

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Chip-integrated metrology serves as an implementation method,possessing the advantages of high efficiency and low cost.The significant revolution of the International System of Units (SI) has freed metrological work from the trouble of physical benchmark and made the methods of reproducing values more flexible.Along with the development of quantum measurement methods,a number of chip-scale metrological standard device have been born.Micro-Electro-Mechanical System (MEMS),microfluidics,and chip-integrated laser are key supporting technologies for chip-integrated metrology.Based on quantum measurement technology,the realization of some fundamental units in the SI,like time,length,temperature,and current,has already taken the shape of chipization.Overall,chip-integrated metrology is still in its infancy,mainly in the form of chip-based sensing elements.In the future,continuous efforts should be made to develop chip-integrated metrological standards instruments and gradually construct a chip-integrated traceability chain to fulfill chip-integrated metrology.

A Review of Mid-infrared Gas Detection Technology Based on Quantum Precision Measurement

ZHU Tianyi, FENG Dianying, XU Feng, DONG Yazhuo, ZHANG Wenshen, HOU Qianqian, LIU Xia, WANG Wei

2024, 44(5):  16-24.  doi:10.12060/j.issn.1000-7202.2024.05.03

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This article reviews mid-infrared gas detection technology based on quantum precision measurements.With the development of the semiconductor industry,the requirements for the purity of electronic process gases continue to increase.Traditional mid-infrared gas detection technology faces sensitivity and accuracy challenges in trace gas detection.This article analyzes in detail the characteristics,application status and limitations of technologies such as fiber evanescent waves,photoacoustic spectroscopy,Fourier transform infrared spectroscopy,tunable diode laser absorption spectroscopy and optical cavity ring-down spectroscopy,and focuses on the introduction of quantum correlation spectroscopy.Mid-infrared gas detection technology breaks through the performance bottleneck of traditional mid-infrared detectors by utilizing photon quantum detectors and frequency up-conversion technology,significantly improving detection sensitivity and signal-to-noise ratio.This technology will become a key research direction in the future and This technological breakthrough provides an important reference for achieving higher-precision trace gas detection.

Evaluation Method and Verification of Uncertainty in THz Antenna Pattern Measurement Based on Planar Near Field

HUANG Chengzu, LIU Xingxun, LIU Ting, XU Xingming

2024, 44(5):  25-31.  doi:10.12060/j.issn.1000-7202.2024.05.04

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Facing with the demand for Tera Hertz(THz) antenna pattern calibration,analyzes and evaluates the measurement uncertainty of planar near field measurement based on the measurement device of THz antenna pattern and the classic planar near field measurement uncertainty analysis model of NIST.And the measurement uncertainty is verified through comparative method.The experimental results indicate that the evaluation method is feasible in the set frequency band and is expected to remain applicable in higher bands.This paper introduces a THz antenna pattern measurement device based on planar near field first,then analyzes the sources of measurement uncertainty one by one,compares and verifies results through far field measurement.And then looks forwards to the future work.

Accurate Measurement of Transfer Impedance and MCM Uncertainty Assessment of Communication Cables

DING Xiang, ZHU Menghan, DENG Xiaoqian

2024, 44(5):  32-38.  doi:10.12060/j.issn.1000-7202.2024.05.05

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To solve the problem that the outer cylinder distribution parameters,joint connection parameters and other tests seriously affect the accuracy of value traceability in the process of testing communication cable transfer impedance using the tri-coaxial method in the field of high-precision measurement and calibration.By separately measuring the S parameters of the fixture calibrator and the cable under test,using the network cascade algorithm to calculate the shielding attenuation,and finally calculating the transfer impedance,the error can be effectively eliminated,aiming to improve the accuracy of the transfer impedance measurement.Starting from the measurement principle of the tri-coaxial method,the standard test plan is analyzed,the two-port S matrix and A matrix conversion and network cascade algorithm are discussed in detail,and an accurate measurement plan for transfer impedance is derived.It was verified through experiments and the Monte Carlo Method (MCM) was used to evaluate the measurement uncertainty,and the evaluation result was U_r=8%（k=2）.

A Method for Intelligently Setting Parameters of the PID Control System of Hydrogen Atomic Frequency Standard

LI Ang, ZHOU Tiezhong, XUE Xiaobo, YI Hang, CHEN Dehao

2024, 44(5):  39-44.  doi:10.12060/j.issn.1000-7202.2024.05.06

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The stable operation of the hydrogen atomic frequency standard is the prerequisite for its important role,and the role of the Proportion Integration Differentiation (PID) control system is to adjust the output frequency of the crystal oscillator part of the hydrogen atomic frequency standard as close to its nominal value as possible,which is an important part of ensuring the stable operation of the hydrogen atomic frequency standard.Although the parameters of the PID control system will not change over time,their values are still mainly adjusted manually or decisions are made based on accumulated knowledge and a large amount of experimental data.Therefore,this paper adopts a new intelligent technology based on the Back Propagation (BP) neural network.The core of this algorithm is feedback adjustment based on the deviation between the output of the PID control system and the expected output.That is,in the back propagation process,feedback functions are used to better adapt to the situation in actual applications,and they are used as learning objects,so that the best performance can be achieved without external interference and the possibility and scope of deviation from expectations can be effectively reduced.The optimization of parameters in the PID control system is achieved through signal forward propagation and error reverse transmission.The final simulation result is that the daily frequency stability of the hydrogen atomic frequency standard is 1.51E-15.After experimental comparison,this method obtained optimal simulation data,thereby improving the stability of the hydrogen atomic frequency standard operation.

Research on On-wafer Calibration Method for PCM Equipment Current Parameters

DING Chen, LIU Yan, QIAO Yue, ZHAI Yuwei, WU Aihua

2024, 44(5):  45-49.  doi:10.12060/j.issn.1000-7202.2024.05.07

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An on-wafer calibration method was provided to solve the problem that the current parameters of the PCM equipment could not to be calibrated on probe end.The on-wafer sampling resistance standards were developed by thin-film sputtering and ion implantation method of semiconductor process.A calibrating system with temperature control function was established,which could calibrate the standards.The calibration results could be traced to the highest national standard of DC resistance parameters.PCM equipment applied voltage to on-wafer sampling resistance standards and parallel connection standard voltmeter.The on-wafer calibration of current parameters 1 nA~100 mA by applying voltage to measure current.The method could carry out effective on-wafer calibration of current parameters for PCM equipment and ensured the accuracy of the current parameters of the PCM equipment on probe end.

Cold-atom Optical Frequency Standard Based on Long-strip Diffuse Laser Cooling

GUAN Xiaolei, ZHANG Jia, GAO Xun, WANG Yu, SHI Tiantian, CHEN Jingbiao

2024, 44(5):  50-54.  doi:10.12060/j.issn.1000-7202.2024.05.08

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Optical frequency standards stabilized by sub-Doppler laser spectroscopy have achieved short-term frequency stability better than 10^-13 level in different atomic and molecular ensembles.However,further improvement in the long-term frequency stability of existing thermal-atom optical frequency standards is challenging due to the influence of collision and Doppler frequency shifts.To address this issue,a cold-atom optical frequency standard based on long-strip diffuse laser cooling is proposed.It innovatively combines cold atoms with the frequency modulation spectroscopy (FMS) stabilization technique,and uses diffuse laser cooling to prepare cold atomic cloud up to 50 cm in length,which significantly increases the number of effective atoms.By probing the cold-atom FMS and locking the output frequency of a 780 nm external cavity diode laser to the ⁸⁷Rb 5²S_1/2（F=2）→5²P_3/2（F=3） cycling transition,the cold-atom optical frequency standard ultimately achieves an in-loop short-term frequency stability of 5×10^-15/τ.In the future,this cold-atom optical frequency standard is expected to be developed into a space cold-atom clock or a wavelength standard,promoting continuous progress in the field of precision measurement.


The Torque Calibration Technology Research of Micro Electromagnetic Components

QI Hongli, MA Xianglong, LI Tao

2024, 44(5):  55-60.  doi:10.12060/j.issn.1000-7202.2024.05.09

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Torque is one of the most important parameters of the micromagnetic devices of inertial navigation system,which is usually from the milli-Nm to 10^-6 Nm.In order to measure 10^-6 Nm torque value of micromagnetic devices,this paper researches a standard torque device,which has a torque calibration and measurement range reaching to 10^-6 Nm.The device adopts the new torque calibration and measurement technology based on the flexure suspension and zero-stiffness theory,designs the ultra-thin,one-piece flexure suspension protection structure,realizes the zero-stiffness suspension structure of the device,and solves the multi-degrees-of-freedom torsional deformation problem of the flexure suspension,so make the micro-torque measurement range expand to 10^-6Nm consequently.Simultaneously,this paper realizes the small torque automatic loading technology,puts forward the idea of automatic loading of milligram (mg) level weights step by step,solves the automatic loading problem of heterogeneous weights,eliminates the impact influence generated by manual loading of traditional small-torque devices,realizes the device's full-range automatic calibration and measurement,and enhances the quantity transmission reliability.Experiments shown that the device has a measurement range from 10^-6 Nm to 10^-4 Nm,and a relative measurement uncertainty better than 1% (k=2).

Design and Implementation of Agile Vector Signal Generator

TIAN Yunfeng, HU Bin, WANG Zhiqiao, WANG Xinyang, HE Wei, JIA Lin

2024, 44(5):  61-67.  doi:10.12060/j.issn.1000-7202.2024.05.10

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In order to meet the needs of wide band agile vector signals for the test of radar systems,communication equipment and the construction of complex electromagnetic environment，using many kinds of ways simultaneously to generate the signal,such as Direct Analog Synthesis(DAS),Phase-Locked Loop(PLL)synthesis,Direct Digital Synthesis(DDS),I/Q digital vector modulate etc.，agile vector signal generate technology is researched.Many key technologies,such as frequency agility,amplitude agility,modulation agility,high speed time synchronization and control,complex electromagnetic signals generation etc.，are broken through.The agile vector signal generator is combinated with the advantages of vector signal generator,agile signal generator and low phase noise signal generator.The advanced technical indicators,such as 40 GHz frequency range,100 ns agile time,1 GHz instantaneous bandwidth etc.，are realized.

Second-order Doppler Frequency Shifts of Ions in Paul Traps

MIAO Shengnan, ZHENG Ying, ZHANG Shengkang, CHEN Haijun, ZHANG Jianwei, WANG Lijun

2024, 44(5):  68-75.  doi:10.12060/j.issn.1000-7202.2024.05.11

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The evaluation of the second-order Doppler frequency shift (SODFS) of trapped ions in Paul traps has been studied in this paper.The motion of confined ions in a Paul trap consists of three components:secular motion,micromotion,and excess micromotion.This paper focused on the ion excess micromotion,which is rarely discussed when evaluating the SODFS of ions.Based on the hypothesis that the ion density is uniformly distributed in the radial direction,a model was proposed to evaluate the total SODFS for an ion ensemble with temperature less than 100 mK in this paper,which consists of three contributions of ion motion.The effectiveness of the model has been verified by molecular dynamics simulations and experiments.The model in this paper offers advantages in accurately evaluating the SODFS for the ion trap,which is appliable for optical clocks based on ions and microwave clocks based on ions,especially those of laser-cooled ion microwave clocks based on large ion clouds.

Research on Quantum Coherence Based Polarization Characteristics of Laser Metrology for Co Directional Transmission in Rubidium Atomic Gas

JIA Yunfeng, LIU Weiping, LI Dong, YU Bing, ZHANG Yunlong, YOU Yue, WANG Nanxi, CHEN Jiejing, LIU Yize

2024, 44(5):  74-80.  doi:10.12060/j.issn.1000-7202.2024.05.12

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To address the issue of polarization metrology during the transmission of laser in the gas medium,a solution is proposed that utilizes the quantum coherence effect of two laser beams propagating in the same direction within the rubidium atomic gas medium.Through the Stokes polarization inversion method to detect the intensity distribution of one of the laser beams,the polarization distribution of the other laser beam can thus be obtained.The specific implementation involves simultaneously passing the two laser beams through the rubidium atomic gas.By altering the polarization direction and ellipticity of one of the laser beams,the intensity and polarization variations of the other detection laser beam after passing through the rubidium atomic gas are investigated.The experimental results were verified by replacing a laser beam with mixed vector light and angular vector light.It is discovered that when the polarization azimuth and ellipticities of the two laser beams are the same,the intensity of the laser reaches its maximum,yet the polarization distribution remains unchanged.For this,a mathematical model of quantum coherence is proposed for explanation,and ultimately,the feasibility of the proposed quantum coherence mathematical model is verified through experiments on the detection of the coherent time of transition energy levels.

IoT and Blockchain Technology Empower the Digital Transformation of Measurement

ZHENG Jianghui, LI Jingrui, GUO Hongyan, WU Hongxia, WANG Liang

2024, 44(5):  81-85.  doi:10.12060/j.issn.1000-7202.2024.05.13

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A metrology management system supported by the Internet of Things and blockchain is proposed to address the quality management issues in the aerospace field and adapt to the development direction of digital transformation in metrology.The main research objective is to improve testing efficiency and ensure data security,focusing on the transmission of out of range values and customer data privacy issues.By integrating IoT technology and blockchain technology,the system achieves real-time data collection,device interconnection,and remote monitoring,while ensuring data immutability and privacy protection.Introduced smart contracts to automate the testing process,and combined with intelligent anomaly detection algorithms and equipment monitoring systems,the problem of out of range value transmission in the measurement process is effectively solved.The measurement management system empowered by the Internet of Things and blockchain technology can capture and process abnormal values in real time,and prevent potential risks of customer data leakage through the privacy protection mechanism of blockchain.This solution provides an efficient,safe,and automated feasible approach for quality management in the aerospace field,creating practical application value for enhancing the competitiveness of metrology testing and customer trust.

The Study on the Measurement of the Ambient Dose Equivalent of Gamma Radiation in n,γ Mixed Radiation Fields Using a G-M Counter

WANG Yuchen, XU Xinyu, LI Chunjuan, LIU Yina, WANG Zhiqiang, DUAN Junyi, LUO Hailong

2024, 44(5):  86-91.  doi:10.12060/j.issn.1000-7202.2024.05.14

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Based on the mechanisms of neutron production and reactions,neutron reference radiation fields are n,γ mixed fields,where the gamma component primarily originates from gamma rays accompanying neutron production and those generated by the interaction of neutrons with materials in the radiation field environment.This paper investigates the application of an energy-compensated Geiger-Müller(G-M) counter in n,γ mixed radiation fields.Using the Monte Carlo (MC) particle transport code MCNP,the energy response of the G-M counter was simulated,and experimental validation was conducted in a gamma reference radiation field.The validation demonstrated that the energy compensation scheme effectively suppresses the over-response in the low-energy region.Utilizing this energy-compensated G-M counter,the ambient dose equivalent of gamma radiation in laboratory radioactive nuclide neutron source fields was measured.This improves the parameters of the reference radiation field and provides support for addressing calibration issues arising from the gamma response characteristics of neutron instruments.

Application of Continuous Thermocouple Temperature Measuring System in High Temperature Aging System

SUN Qiang, HUANG Xianwu, JIN Ran, LI Yinchuan, FU Jie

2024, 44(5):  92-96.  doi:10.12060/j.issn.1000-7202.2024.05.15

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In order to realize the real-time monitoring of the temperature in the effective working area of the high temperature aging system,and avoid the failure and damage of the chip or electronic component caused by abnormal temperature,according to the principle that the output thermoelectric potential of the continuous thermocouple is always corresponding to the highest temperature in the temperature sensing section,a set of real-time temperature measurement system using the continuous thermocouple as the temperature sensing element is built.The system is simple in layout and low in cost.The real-time temperature measurement system is used to verify the test data of the constant state and the temperature gradient state respectively,and the expected effect can be achieved.The system can effectively monitor the aging system working area temperature,achieve centralized monitoring,and according to the chip or electronic components aging temperature,be free to set early warning and alarm temperature points.