Sergei V. Sazonov

Dynamics of Ultimately Short Pulses in Partially Absorbing Media

Propagation of broad-band ultimately short light pulses in a partially absorbing medium is analyzed in the framework of the three-level model. Nonlinear wave equations are obtained describing propagation of light pulses in media with quadratic (all three transitions are allowed) or cubic (one of the transitions is forbidden) nonlinearity in the range of optical transparency or with the sine-Gordon-type nonlinearity in the region of absorption. Using the averaged variational principle, the approximate solutions of equations in the form of unipolar soliton-like signals are found and conditions of their transverse stability are determined. A stable propagation of a broad-band pulse is shown to be possible under conditions when monochromatic signals exhibit self-focusing.

Photon echo excited in multilevel quantum media by ultimately short pulses

The photon echo excitated in a multilevel quantum medium by two or more ultimately short pulses with duration down to one period of optical oscillations is studied theoretically. It is shown that the number of echo responses formed in the system depends on the number of quantum levels covered by the spectrum of the exciting pulses and strongly increases with this number. General equations for the spatio-temporal characteristics of the multipulse echo signals are obtained.

Multifrequency photon echo generated by extremely short pulses

A photon echo in a multilevel quantum medium excited by two extremely short pulses with durations of less than one period of oscillation of the light is investigated theoretically. It is shown thatQ echo signals (Q is the number of allowed transitions) can form at each frequency of the allowed transitions, and the number of echo responses for all the allowed transitions equalsQ2. Of these,Q(Q−1) signals are separated in both time and space. The otherQ echo signals of all the allowed frequencies all arise at the time 2τ21 (τ21 is the time interval between application of the first and second pulses to the medium) and are collinear with one another.