Rydberg electromagnetically induced transparency in 40K ultracold Fermi gases

Abstract

We report the measurement of the electromagnetically induced transparency (EIT) with Rydberg states in ultracold 40 K 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.

Optimal preparation of Bose and Fermi atomic gas mixtures of 87Rb and 40K in a crossed optical dipole trap

“…It is shown that the atomic numbers of 87 Rb and 40 K decrease simultaneously at each stage of the evaporation in the crossed ODT, and the atoms 87 Rb still exist even the number of 40 K atoms is at its maximum, which ensures that we can obtain a standard atomic sample number by optimizing all steps in the ODT. Nearly N = 2.6 × 10 6 ultracold 40 K atoms 063402-3 are prepared at a temperature of 0.35 T F during the process of sympathetic cooling with 87 Rb, where T F = h ω is the Fermi temperature, [57] ω = (ω x ω y ω z ) 1/3 2π × 80 Hz is the geometric mean of the optical trap in our experiment, N is the particle number of 40 K atoms, and k B is Boltzmann's constant. As we decrease the intensity of the ODT step by step shown in Fig.…”