Two-channel pulse propagation in a tripod four-level atomic medium
摘要
In this paper, we study the pulse propagation in a four-level tripod scheme of the 87Rb atomic system excited by two strong controlling fields (coupling and signal fields) and one weak probe field under electromagnetically induced transparency (EIT). By adjusting the frequency or the intensity of the two controlling laser fields appropriately, the response of the atomic system can exhibit single or double EIT windows. In the EIT spectral domain, we find a stable probe pulse propagation as a soliton without considering the nonlinearities as in the conventional medium. In particular, in this four-level tripod configuration with the simultaneous appearance of two EIT windows, we also obtain two different probe frequency domains simultaneously where the probe pulse propagates as solitons. The influence of the controlling laser frequency and intensity on the soliton-like pulse shape of the probe laser beam are also investigated. This study may be useful for studies on multi-channel all-optical switching and optical memory.