Physical Review A
Rydberg excitation spectrum of K40 ultracold Fermi gases
Donghao Li, Guoqi Bian, Jie Miao, Pengjun Wang, Zengming Meng, Liangchao Chen, Lianghui Huang, Jing Zhang
Abstract
We report the measurement of the Rydberg excitation spectrum by two-photon process in ultracold $^{40}\mathrm{K}$ Fermi gases. Two different methods are employed to measure the Rydberg excitation spectrum, depending on the power of the probe laser. One scheme is to reduce atomic losses by means of electromagnetically induced transparency. The other is to enhance the atomic losses by spontaneous avalanche ionization due to the strong Rydberg-Rydberg interactions. We verify the consistency of both of the methods. The highest Rydberg states detectable in our experiment are limited to $n\ensuremath{\le}62$ due to the competition between the long Rydberg blockade effective range and the limited atomic cloud size.