Experimental Study Of Quantum Interference Effects In Coupled Cold Atom-Cavity System

Cavity Quantum Electrodynamics is an important means to study dynamics of quantum systems, and it provides a system to observe quantum behavior of microscopic objects in a laboratory environment. In this paper, laser cooling and trapping of rubidium atoms, combined with the optical resonator is used to study the cold atoms in an optical cavity coupled system of quantum interference effects. The main contents include:1. An experimental system based on cold atoms coupled Fabry-Perot cavity is designed and implemented. The number of cold Rb atoms captured in the magneto-optical trap of this system is 2×106, and the empty cavity finesse is 300.2. We propose that Raman pump-probe spectroscopy method can be utilized to extract temperature information of the cold atoms. The proposed scheme is applied for the magneto-optical trap of the 85Rb atoms. In the experiment, the existence of dispersion-like subnatural profile is interpreted in terms of stimulated Raman processes as the trapping and probe lasers interact with the cold atoms simultaneously. By analyzing the dispersion-like narrow Raman profile with the theoretical model, we estimate the temperature of the trapped cold 85Rb atoms, which is about 230?K. Compared to the time-of-flight method, this scheme provides a relatively simple method to estimate cold atom temperature.3. We present the experimental observation of the Fano-type interference in a coupled cavity-atom system by confining the laser-cooled 85Rb atoms in an optical cavity. The asymmetric Fano profile is obtained through quantum interference in a three-level atomic system coherently coupled to a single mode cavity field. The observed Fano profile can be explained by the interference between the intra-cavity dark state and the polariton state of the coupled cavity-atom system. The possible applications of our observations include all-optical switching, optical sensing and narrow band optical filter.