不稳定原子核的基本性质反映了核的内在结构和有效相互作用，可用于研究不稳定核的奇特结构。激光核谱技术通过测量核外电子光谱的超精细结构和同位素移位，可以核模型无关地提取原子核的多个基本性质，是研究不稳定核性质和结构的有力工具之一。多步激光共振电离方法是测量原子或离子超精细结构和同位素移位的方法之一。基于此，国际上发展了多种共振电离谱实验技术，用于放射性核束装置上开展不稳定核基本性质和结构研究。本文首先介绍了激光共振电离方法，以及由此发展的各种共振电离激光谱实验技术。随后详细讨论了近十年来刚发展起来的共线共振电离谱技术。此技术可同时实现超精细结构谱的高分辨和高灵敏度测量，正在核素版图大质量范围内的不稳定核性质和结构研究中发挥重要作用。最后分析了用于国内放射性核束装置的共振电离激光谱技术的发展现状及应用前景。

We report the measurement of the electromagnetically induced transparency (EIT) with Rydberg states in ultracold K40 Fermi gases, which is obtained through a two-photon process with the ladder scheme. Rydberg–EIT lines are obtained by measuring the atomic losses instead of the transmitted probe beam. Based on the laser frequency stabilization locking to the superstable cavity, we study the Rydberg–EIT line shapes for the 37s and 35d states. We experimentally demonstrate the significant change in the Rydberg–EIT spectrum by changing the principal quantum number of the Rydberg state (n=37/52 and l=0). Moreover, the transparency peak position shift is observed, which may be induced by the interaction of the Rydberg atoms. This work provides a platform to explore many interesting behaviors involving Rydberg states in ultracold Fermi gases.

In this article, taking advantage of the special magnetic shieldings and the optimal coil design of a transportable Rb atomic fountain clock, the intensity distribution in space and the fluctuations with time of the quantization magnetic field in the Ramsey region were measured using the atomic magneton-sensitive transition method. In an approximately 310 mm long Ramsey region, a peak-to-peak magnetic field intensity of a 0.74 nT deviation in space and a 0.06 nT fluctuation with time were obtained. These results correspond to a second-order Zeeman frequency shift of approximately (2095.5±5.1)×10-17. This is an essential step in advancing the total frequency uncertainty of the fountain clock to the order of 10-17.

We present a method to precisely determine the hyperfine structure constants of the rubidium 5D5/2 and 7S1/2 states in a cascade atomic system. The probe laser is coupled to the 5S1/2→5P3/2 hyperfine transition, while the coupling laser is scanned over the 5P3/2→5D5/2(7S1/2) transition. The high-resolution double-resonance optical pumping spectra are obtained with two counter-propagating laser beams acting on rubidium vapor. The hyperfine splitting structures are accurately measured by an optical frequency ruler based on the acousto-optic modulator, thus, the magnetic dipole hyperfine coupling constant A and quadrupole coupling constant B are determined. It is of great significance for the atomic hyperfine structure and fundamental physics research.

We report the recent progress of our pulsed optically pumped (POP) vapor cell rubidium clock with dispersive detection. A new compact physics package is made. A rubidium cell with a high precision buffer gases mixing ratio is obtained, and the temperature controlling system is renovated to reduce fractional frequency sensitivity to temperature variation. The resolution of the servo control voltage is also optimized. With these improvements, a clock frequency stability of 3.53×10 13 at 1 s is obtained, and a fractional frequency stability of 4.91×10 15 is achieved at an average time of τ=2000 s.