Department of Physics and Laboratory for Quantum Optics, East China Normal University, Shanghai 200062, China; Department of Electronics, Fuzhou University, Fuzhou 350002, China
Abstract:
The experimentally observed special line-shape induced by the interaction between two counter-propagating equal-frequency fields and an Y-type four-level system with two mixed upper levels has been analyzed theoretically. Serious line-shape variations of the two-photon transitions due to the quantum interference are discussed and predicted.