The results of theoretical research of the propagation effect of an ultrashort optical pulse under the conditions of coherent interaction with two resonant transitions are presented. One of the transitions is tuned to exact resonance with the pulse carrier frequency; the other is distanced by much more than the pulse spectral width, thus the adiabatic following approximation may be applied to it. The interaction between the pulse and the far-from-resonance transition is described by the wave equation with the nonlinear index of refraction in the form of the Lorentz function of the field amplitude. This wave equation is solved together with the Bloch equations for the exact resonant transition. The solution in the form of the stationary phase-modulated pulse is obtained, and (pi) -pulse of self-induced transparency is the special case of this solution. The obtained solution has the area under the pulse envelope less than (pi) , and with increasing the absorption coefficient of the far-from-resonance transition the pulse area decreases. The effect can be used for reducing the transparency threshold of the resonant medium below (pi) .

Date Published: 10 June 1997
PDF: 7 pages
Proc. SPIE 3177, CIS Selected Papers Nonlinear Dynamics of Laser and Optical Systems, (10 June 1997); doi: 10.1117/12.276183

Published in SPIE Proceedings Vol. 3177:
CIS Selected Papers Nonlinear Dynamics of Laser and Optical Systems
Valery V. Tuchin, Editor(s)