基于原子的射频识别标签近场散射场矢量测量

基于原子的时间/频率、长度以及磁场、微波电场等方面的量子精密测量近年来引起广泛关注。里德堡原子作为微波精密测量工具，具有可溯源性好、空间分辨率高以及探测灵敏度高等优势。通过室温铯里德堡原子的电磁诱导透明光谱特征分析实现了微波电场矢量空间高分辨测量。利用铯原子蒸气池中共线的耦合光和探测光形成了6S_1/2-6P_3/2-51D_5/2的阶梯型三能级系统，5.365 GHz微波电场将诱导相邻里德堡态51D_5/2-52P_3/2的共振跃迁，导致阶梯型三能级系统的电磁诱导透明光谱发生Autler-Townes分裂。通过计算光谱的分裂间隔可得到可溯源至普朗克常数的微波电场强度，微波电场测量的空间分辨率达到1/31被测微波波长。特别是提出一种新的微波电场极化方向测量方法，解决了基于里德堡原子进行微波电场极化方向测量时无法分辨互补角的问题。通过对射频识别标签的近场散射场进行矢量测量，实现了标签角度的有效识别，角度分辨率达到1.64°，测量结果与有限元分析方法仿真结果吻合地很好。该研究对于微波电场空间高分辨成像、射频识别标签的设计和识别以及电磁兼容测试等方面具有重要价值。

Atom-Based Vector Measurement of Near Field Scattering Field of Radio Frequency Identification Tag

Atom-based quantum precision measurement of time,frequency,length,magnetic field and other physical quantities has attracted widespread attention in recent years.As a precision microwave measurement sensor,Rydberg atoms have the advantages of good traceability,high detection sensitivity and spatial resolution.In this paper,the cesium Rydberg atoms at room temperature are used to realize high-resolution vector measurement of microwave electric field based on the characteristic of the electromagnetically induced transparency spectroscopy.The microwave electric field with the frequency of 5.365 GHz couples the Rydberg transition of 51 D_5/2-52 P_3/2.The electromagnetically induced transparency spectrum of a 6 S_1/2-6 P_3/2-51 D_5/2 ladder system will split because of the Autler-Townes effect.The intensity of the microwave electric field is obtained by calculating the splitting separation.The spatial resolution reaches 1/31 of the measured microwave wavelength.A new method for measuring the polarization direction of microwave electric field is proposed,which solves the problem that the complementary angle cannot be identified in the measurement of the polarization direction of microwave electric field.Through the near-field vector measurement of the scattering field of a radio frequency identification tag,the effective angular resolution of the tag is achieved and reaches 1.64°.The measurement results are in good agreement with the simulation results of the finite element analysis method.This paper present the valuable explore for the microwave electric field spatial high-resolution imaging,offer the evaluation tools for the design and identification of radio frequency identification tags,and electromagnetic compatibility testing.