Abstract

We study the propagation of two partially overlapping laser pulses E_1,2(t) in an absorbing medium of three-level A system with energy levels E₀< E₂ < E₁, which are initially in the lower stare. A probe pump laser pulse resonantly connects levels 0 and 1 and the coupling pulse E₂(t) connects levels 1 and 2. The probe laser intensity is comparable to that of the coupling laser. The interaction of the coupling pulse with atoms begins and ends earlier than the interaction with probe laser. It is assumed that a pulse duration is short enough to neglect damping of atomic states. It is known that complete transfer of population into excited atomic state 2 can be achieved if both fields are changing sufficiently slowly (see e.g. [1]). This phenomena, which is closely related with coherent population trapping, is named adiabatic population trapping (APT) [1.2].

© 1998 IEEE