铯原子里德伯态精细结构测量  

Measurement of the fine structure of cesium Rydberg state

作　　者：裴栋梁 何军[1,2,3] 王杰英 王家超 王军民[1,2,3] 

机构地区：[1]山西大学光电研究所,太原030006 [2]山西大学量子光学与光量子器件国家重点实验室,太原030006 [3]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19期62-68,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61475091;61227902);国家重点研发计划(批准号:2017YFA0304502);山西省高等学校科技创新项目(批准号:2017101)资助的课题~~

摘　　要：里德伯态光谱是测量里德伯态能级结构和中性原子间相互作用的常用技术手段,特别是高精度的里德伯光谱,可以测量室温原子气室中由偶极相互作用等导致的原子能级频移.在实验中利用反向的852 nm激光和509 nm激光实现了室温原子气室中铯原子6S_(1/2)—6P_(3/2)—57S(D)跃迁的级联双光子激发,实现了里德伯态原子的制备.基于阶梯型电磁诱导透明获得了铯原子里德伯态的高分辨光谱.实验中,基于速度选择的射频边带调制技术,对光谱信号进行了频率标定,测量了铯原子里德伯态57D_(3/2)和57D_(5/2)的精细分裂,分裂间隔为(354.7±2.5)MHz,与理论计算结果基本一致.速度选择的射频调制光谱可以实现里德伯态原子的能级分裂测量,其测量精度对于单光子跃迁的绝对激光频率不敏感;实验中影响57D_(3/2)和57D_(5/2)精细分裂间隔测量精度的主要因素是功率加宽导致的电磁感应透明信号的展宽和509 nm激光频率扫描的非线性.The spectra of Rydberg atoms are of great significance for studying the energy levels of Rydberg atoms and the interaction between neutral atoms, especially, the high-precision spectra of Rydberg atoms can be used to measure the energy level shifts of Rydberg atoms resulting from the dipole-dipole interactions in room-temperature vapor cells. In this paper we report the preparation of cesium Rydberg states based on the cascaded two-photon excitation of 509 nm laser and 852 nm laser in opposite, and the measurements of the fine structure of cesium Rydberg states. In this experiment,the 509 nm laser is generated by the cavity-enhanced second-harmonic generation from 1018 nm laser with a periodicallypoled KTP crystal and has a maximum power of about 1 W, and the 852 nm probe laser is provided by an external-cavity diode laser with a maximum output power of 5 mW and a typical line width of 1 MHz. By scanning the frequency of509 nm coupling laser, it is presented that the Doppler-free spectra based on electromagnetically-induced transparency（EIT） of 509 nm coupling laser and 852 nm probe laser. The velocity-selective EIT spectra are used to study the spectral splitting of 6S（1/2）—6P（3/2）—57S（D） ladder-type system of cesium Rydberg atoms in a room-temperature vapor cell. The powers of 852 nm probe laser and 509 nm coupling laser are 0.3 μW and 200 mW, respectively. Their waist radii are both approximately 50 μm. The intervals of hyperfine splitting of the intermediate state 6P（3/2）（F＇ = 3,4,5） and fine splitting of 57D（3/2） and 57D（5/2） Rydberg states are measured by a frequency calibrating. Concretely, the velocity-selective spectrum with a radio frequency（RF） modulation of 30 MHz is used as a reference to calibrate the Rydberg fine-structure states in the hot vapor cell, where the RF frequency precision is smaller than a hertz on long time scales and the EIT linewidth is smaller than 13 MHz. The experimental value of the fine structure splitting of 57D3/2 and 57D5/2 Rydberg

关 键 词：里德伯态 电磁感应透明 精细结构 超精细结构 

分 类 号：O562[理学—原子与分子物理]