Physical Review A
Electromagnetically induced absorption in a bichromatic laser field
A. A. Zhukov, Sergei A. Zibrov, G. V. Romanov, Yaroslav O. Dudin, Vitali V. Vassiliev, Vladimir L Velichansky, Valery P. Yakovlev
Abstract
In this paper we describe experimentally and theoretically the increase in the electromagnetically induced absorption (EIA) resonance under the influence of an additional optical field. EIA was observed on the cycling transition of the rubidium ${\text{D}}_{2}$ line in the Hanle configuration in the presence of the second-laser field acting on an open transition coupled with a cycling one via a common ground state. We present results obtained for different polarization orientations and propagation directions of the two laser beams. A systematic theoretical analysis based on the optical Bloch equations explains most of the experimental data. A lot of attention is also paid to a qualitative understanding of the EIA---its resonance shape, amplitude, and the response to the additional optical fields.