物理学报2017，Vol.66Issue(19)：68-75,8.DOI:10.7498/aps.66.193701
铯原子里德伯态精细结构测量
Measurement of the fine structure of cesium Rydberg state
摘要
Abstract
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 periodically-poled 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 linewidth of 1 MHz. By scanning the frequency of 509 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 6S1/2—6P3/2—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 6P3/2(F′ = 3, 4, 5) and fine splitting of 57D3/2 and 57D5/2 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 states is (354.7 ± 2.5) MHz, that is in consistence with the value of 346.8 MHz calculated by Rydberg-Ritz equation and quantum defects of 57D3/2 and 57D5/2 Rydberg states. The experimental values of hyperfine splitting of intermediate state 6P3/2(F′ = 3, 4, 5) are also coincident with the theoretical calculated values. The dominant discrepancy existing between the experimental and calculated results may arise from the nonlinear correspondence of the PZT while the 509 nm wavelength cavity is scanned, and the measurement accuracy influenced by the spectral linewidth. The velocity-selective spectroscopy technique can also be used to measure the energy level shifts caused by the interactions of Rydberg atoms.关键词
里德伯态/电磁感应透明/精细结构/超精细结构Key words
Rydberg state/electromagnetically induced transparency/fine structure/hyperfine structure引用本文复制引用
裴栋梁,何军,王杰英,王家超,王军民..铯原子里德伯态精细结构测量[J].物理学报,2017,66(19):68-75,8.基金项目
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)和山西省高等学校科技创新项目(批准号: 2017101)资助的课题.Project supported by the National Nature Science Foundation of China (Grant Nos. 61475091, 61227902), the National Key Research and Development Program of China (Grant No. 2017YFA0304502), and the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province, China (Grant No. 2017101). （批准号: 61475091, 61227902）
