基于冷里德堡原子电磁感应透明的微波电场测量  

Measurement of microwave electric field based on electromagnetically induced transparency by using cold Rydberg atoms

作　　者：周飞 贾凤东 刘修彬 张剑 谢锋 钟志萍 Zhou Fei;Jia Feng-Dong;Liu Xiu-Bin;Zhang Jian;Xie Feng;Zhong Zhi-Ping(School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Institute of Nuclear and New Energy Technology,Collaborative Innovation Center of Advanced Nuclear Energy Technology,Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education,Tsinghua University,Beijing 100084,China;China and CAS Center for Excellence in Topological Quantum Computation,University of Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]中国科学院大学物理科学学院,北京100049 [2]清华大学核能与新能源技术研究院,先进核能技术协同创新中心,先进反应堆工程与安全教育部重点实验室,北京100084 [3]中国科学院大学,中国科学院拓扑量子计算卓越中心,北京100190

出　　处：《物理学报》2023年第4期185-192,共8页Acta Physica Sinica

基　　金：北京市自然科学基金(批准号:1212014);中国科学院重点研究计划(批准号:XDPB08-3);中央高校基本科研业务费专项资金;国家重点研发计划(批准号:2017YFA0304900,2017YFA0402300)资助的课题。

摘　　要：在磁光阱中利用冷原子温度低,多普勒展宽小的优势获得了窄线宽的里德堡电磁感应透明(EIT)谱峰,结合Autler-Townes分裂效应(EIT-AT分裂)分别测量了多个频率的微波电场强度.结果显示,EIT-AT分裂间距与微波电场强度呈很好的线性关系,EIT-AT分裂方法可测量的微波电场强度线性区的下限可达222μV/cm,这个下限比传统热原子蒸汽池中EIT-AT分裂线性区的下限5 mV/cm提高了大约22倍,这对极弱微波电场的绝对校准非常有帮助.我们进一步利用EIT共振处探测光透过率的变化测量微波电场强度,对应的最小测量值可以小于1μV/cm,相应的灵敏度可达到1μV·cm-1.Hz-1/2.这些结果展示了冷原子样品在微波电场测量及其绝对校准方面的优势.Microwave electric fields are measured by using cold Rydberg atoms.We obtain spindle-shaped cold atomic clouds in a magneto-optical trap and then pump the cold atoms to quantum state 5S1/2,F=2,mF=2 by using an optical-pump laser.We obtain the Rydberg electromagnetic induction transparency(EIT) spectrum peak with narrow linewidth by the low temperature and small residual Doppler broadening.The results show that the typical EIT linewidth with 16 μK cold atoms is about 460 kHz which is 15 times narrower than that of7 MHz obtained in the thermal vapor cell.The microwave electric field amplitude is measured by AntlerTownes splitting(EIT-AT splitting) in the cold atoms at frequencies of 9.2,14.2 and 22.1 GHz,receptively.The results show that there is a good linear relationship between the EIT-AT splitting interval and the microwave electric field amplitude.The lower limit of the microwave electric field amplitude that can be measured in the linear region can reach as low as 222 μV/cm,which is about 22 times larger than the lower limit in the traditional thermal vapor cell about of 5 mV/cm.The improvement of the lower limit by EIT-AT splitting method is roughly proportional to the narrowing EIT line width by cold atom samples.This demonstrates that benefiting from the smaller residual Doppler effect and the narrower EIT linewidth in cold atoms,the cold atom system is more advantageous in the experimental measuring of the weak microwave electric field amplitude by using the EIT-AT splitting method.This is of great benefit to the absolute calibration of very weak microwave electric fields.Furthermore,the lower limit of the microwave electric field amplitude that can be measured is smaller than 1 μV/cm by using the change of transmittance of the prober laser at the EIT resonance,and the corresponding sensitivity can reach 1 μV·cm-1·Hz-1/2.These results demonstrate the advantages of cold atomic sample in microwave electric field measurement and its absolute calibration.

关 键 词：微波电场传感器 里德堡原子 电磁感应透明 

分 类 号：O441.3[理学—电磁学]