Abstract

The possibility to render optically thick media transparent for coherent laser radiation via electromagnetically induced transparency (EIT) gained considerable interest over the last years [1,2]. Here we study a propagation of two short laser pulses in an absorbing three-level medium (Fig.1a) under conditions of EIT. We consider two cases: the coherent population trapping (CPT) and the adiabatic population transfer (APT). In the first case the duration of the coupling pulse G₂ is larger than the duration of probe pulse G₁ (Fig. 1b). In the second case both pulses have identical form, but they switch on and switch off in counterintuitive sequence (Fig.1c). It is assumed that envelopes of pulses vary slowly enough and satisfy the criterion of adiabaticity |G_1,2|T_1,2 ≫ 1 (G_1,2 — the Rabi frequencies; T_1,2 — the durations of interacting pulses). This adiabaticity condition can be achieved for strong enough pulses even if the pulses duration is shorter than the relaxation time of an intermediate resonant state.

© 2000 IEEE