Optical nonreciprocity of a single two-level atom in a cavity

Abstract

We analyze the transmission character of a single-mode cavity containing a resonant two-level atom. Such a simple structure exhibits optical nonlinearity and spatial symmetry breaking, as well as time-reversal symmetry breaking. We perform a detailed analysis in the Purcell regime and find out that there is giant optical nonreciprocity in proper parameter space. Therefore, it is feasible to assemble such a simple atom–cavity structure to realize an acceptable optical nonreciprocal device after carefully designing.