Full Quantum Theory of Transient-State Electromagnetically Induced Transparency**The project supported by National Fundamental Research Program under Grant No. 2001CB309310, National Natural Science Foundation of China under Grant Nos. 10325523, 90203018, and 10075018, and the Key Projects of the Education Ministry of China and the Educational Committee of Human Province of China under Grant Nos. 03094 and 02A026

Abstract

We develop a full quantum theory of transient-state electromagnetically induced transparency (EIT) in the vapor of three-level -type atoms interacting with probe and coupling lasers. As applications of the full quantum theory, we show that transient-state EIT medium exhibits normal dispersion and find that group velocities of both coupling and probe lasers are greatly reduced. It is shown that the group velocity of the probe laser in the transient-state EIT case is equal to that in the adiabatic EIT case and that the coupling laser group velocity in the transient-state EIT is generally less than that in the adiabatic EIT.