Parametric resonances in a gas of three-level atoms in an external field

Nadeem A. Ansari, Muhammad Suhail Zubairy, Julio R. Gea-Banacloche

We have studied the amplification of a single-mode electromagnetic field by an atomic system with a three-level cascade structure in two-photon resonance conditions when the top and bottom levels are mixed coherently by a strong external resonant field. We find different kinds of phase-sensitive amplification for different values of the driving field strength. For a very high driving field and near one-photon resonance, the system approaches an ideal parametric amplifier.

L. G. Malyshev, L. N. Novikov

Michael Z. Smirnov

The parametric resonances and the quasi-level structure of an atom strongly driven by a near-resonant amplitude-modulated optical field are studied theoretically. An approximate analytical solution of the density-matrix equations of motion is obtained for two-level and three-level atoms. Based on this solution the quasi-level shifts are analyzed, and the conditions for the quasi-levels to cross each other are derived. Expressions are given for the probe-wave absorption/gain spectrum near the parametric resonance and far from it. It is pointed out that the parametric resonances appear when the pumping field sidebands are tuned to resonance with some transitions among the quasi-levels.

I. P. Zapesochny, О. Б. Шпеник

Denis A. Demidov, N. K. Solovarov

Sergey Siparov

The probe-wave absorption spectrum calculation is presented for the case when a two-level atom or ion in the resonant field of laser radiation is subjected to low-frequency external action in such a way that parametric resonance takes place and the fine structure appears on the probe-wave absorption coefficient plot.