里德堡原子微波调幅信号解调系统原子汽室高灵敏工作点分析  

High Sensitivity Operating Point of Atom Cell in Rydberg Atom Microwave Amplitude Modulation Signal Demodulation System

作　　者：喻强 饶睿坚 吴金云 张引发[1] Yu Qiang;Rao Ruijian;Wu Jinyun;Zhang Yinfa(College of Information and Communication,National University of Defense Technology,Wuhan 430035,Hubei,China)

机构地区：[1]国防科技大学信息通信学院,湖北武汉430035

出　　处：《光学学报》2024年第20期269-276,共8页Acta Optica Sinica

基　　金：国家自然科学基金专项项目(62341126);国防科技大学基金(YJKT-RC-2112,ZBZH-ZH-2311,24ZZCXJDZ41)。

摘　　要：研究基于里德堡原子的微波调幅信号解调系统中,原子汽室的高灵敏工作点与耦合光、微波、里德堡原子能级参数之间的关系。首先,为了描述在解调微波调幅信号过程中,原子汽室对调幅微波中基带信号的敏感程度,定义原子汽室透射率对微波电场强度幅值一阶导数的绝对值为原子汽室增益系数,并推导出原子汽室增益系数的理论表达式。其次,通过数值仿真和理论分析得到:在里德堡原子能级固定且频率零失谐的条件下,通过调整耦合光和微波载波的电场强度,可以使原子汽室增益系数出现极大值,此时原子汽室处于高灵敏工作点。最后,当微波处于C波段范围内,在原子汽室频率零失谐且原子主量子数小于70的条件下,通过数值仿真计算得到C波段微波所有|3〉、|4〉能级参数和对应的原子汽室增益系数的极值,同时分析影响原子汽室增益系数的因素;该结果可为实现原子汽室处于高灵敏工作点提供理论依据。仿真表明:在微波C波段,当^(133)Cs的|1〉、|2〉、|3〉、|4〉能级分别为6S_(1/2)、6P_(3/2)、60D_(3/2)、61P_(1/2),并且在零失谐条件下,微波频率为4.03012 GHz,耦合光和微波载波电场强度分别为3.929343×10^(4)V m和2.144006×10^(-4)V m时,1 cm长的原子汽室增益系数最大值为1688.2 m/V。Objective The Rydberg atom system,through the effects of electromagnetically induced transparency(EIT)and AutlerTownes(AT)splitting,can strongly respond to weak microwave signals.This makes it a promising candidate for receiving and demodulating microwaves with greater sensitivity than traditional systems.Currently,two methods exist for demodulating amplitude modulation(AM)microwave signals:the indirect method and the direct method.In the indirect method,the process involves scanning the probe or coupling laser frequency near the zerodetuning point and measuring the frequency separation between the split peaks in the probe transmission spectrum.This separation is proportional to the microwave electric field(Efield)strength,which allows for the calculation of the microwave Efield intensity.The direct method,on the other hand,involves detecting variations in the probe laser transmission intensity using a photodetector while the Rydberg atom system is at zerodetuning.The resulting photogenerated current approximates the baseband signal.In this process,the transmittance of the Rydberg atom cell varies with the amplitude of the AM signal.The sensitivity of the atom cell to the baseband signal is reflected in how the atom cell’s transmittance changes with variations in microwave amplitude.A small change in the baseband signal amplitude that leads to a significant change in the atom cell’s transmittance indicates high sensitivity.In this study,we focus on exploring the relationship between the Rydberg atom cell transmittance and the coupling laser,microwave field,and Rydberg atom energy levels to identify the highsensitivity operating points of the Rydberg atom cell during direct demodulation.To our knowledge,no prior research has explored the relationship between the coupling laser,microwave carrier,and the highsensitivity operating points of the Rydberg atom cell.In addition,there is no research on enhancing atom cell sensitivity by selecting appropriate atom energy levels,microwave frequencies,and coupling laser

关 键 词：里德堡原子 调幅信号 跃迁偶极矩 拉比频率 透射率 

分 类 号：TN852[电子电信—信息与通信工程]