超冷铯Rydberg原子的Autler-Townes分裂  

Autler-Townes splitting of ultracold cesium Rydberg atoms

作　　者：薛咏梅 郝丽萍[1] 焦月春[1,2] 韩小萱 白素英[1] 赵建明 贾锁堂[1,2] 

机构地区：[1]量子光学与光量子器件国家重点实验室,山西大学激光光谱研究所,太原030006 [2]山西大学极端光学协同创新中心,太原030006

出　　处：《物理学报》2017年第21期276-281,共6页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2017YFA0304203);国家自然科学基金(批准号:11274209,61475090,61775124),国家自然科学基金重点项目(批准号:11434007);长江学者和创新团队发展计划(批准号:IRT13076);山西省留学基金(批准号:2014-009)资助的课题~~

摘　　要：主要研究超冷铯Rydberg原子阶梯型三能级系统的Autler-Townes(A-T)分裂.铯原子基态6S_(1/2)、第一激发态6P_(3/2)和Rydberg态形成阶梯型三能级系统,强耦合光共振作用于6P_(3/2)(F′=5)→34D_(5/2)的跃迁,探测光由偏振光谱锁定在6S_(1/2)(F=4)→6P_(3/2)(F′=5)的跃迁,并由双通的声光调制器在其共振跃迁附近扫描,形成的Rydberg原子A-T分裂谱由单光子计数器探测.A-T光谱的双峰间距与耦合光的拉比频率成正比,实验结果与理论计算在耦合光拉比频率Ω_c<2π×9 MHz时符合得很好,在拉比频率Ω_c>2π×9 MHz时,测量的A-T分裂比理论计算值小13%.产生偏差的主要原因是由于较大的耦合光拉比频率Ω_c增加了激发的Rydberg原子数,Rydberg原子间的相互作用产生了较大的退相干率所致.Autler-Townes（A-T） splitting, known as an AC Stark effect, shows a change of an absorption/emission spectral line of a probe beam when an oscillating field is tuned in resonance with the atomic or molecular transition. The A-T splitting is observed in different three-level atoms and widely investigated in a vapor cell and in a magneto-optical trap（MOT）. The A-T splitting plays an important role in the atom-based microwave electric-field measurements where a cascade three-level system involving Rydberg state is adopted.In this work, an A-T splitting is observed in an ultracold cesium Rydberg gas, which is cooled down to about 100 μK and center density is about 10^（10） cm^（-3） in a conventional MOT by using the laser cooling technology. We present the A-T spectrum in a ladder three-level atomic system involving a 34 D（5/2） Rydberg state. The cesium ground state（6 S（1/2））,excited state（6 P（3/2）） and Rydberg state（34 D（5/2）） constitute a Rydberg three-level system. A coupling laser, locked to the Rydberg transition by using a Rydberg electromagnetically induced transparency signal that is obtained from a cesium room-temperature vapor cell, couples 6 P（3/2）（F′=5）→34 D（5/2） Rydberg transition. A weak probe laser, stabilized to a ground-state transition by using a polarization spectroscopy, is swept, covering the transition 6 S（1/2）（F=4）→6 P（3/2）（F′=5） with a double-passed acousto-optic modulator. The probe and coupling lasers are counter-propagated through the MOT center. The power of probe light is 200 pW, corresponding Rabi frequency Ωp=2π×1.05 MHz. During the experiment, 50 μs after turning off the trapping laser, both the coupling and probe beams are switched on and last100 μs. The A-T spectrum as a function of the probe detuning is detected with a single-photon counter module detector.We use Gaussian multiple peak fitting to obtain the positions of the A-T peaks and the A-T splitting. The measured A-T splitting is proportional to

关 键 词：RYDBERG原子 Autler-Townes分裂 阶梯型三能级系统 

分 类 号：O562[理学—原子与分子物理]