Phase memory in conditions of optical instability development

Abstract

Regularities in the transformation of optical coherence in the model three-level system, resulting from instability development and emission of a superradiance pulse, are considered. It is shown that the superradiance eliminates optical coherence on the adjacent optically allowed transitions and induces optical coherence on the optically forbidden transition. This, in turn, makes it possible to observe new effects of photon-echo type, some of which are described in the present paper.

Phase Memory Preserving Harmonics from Abruptly Autofocusing Beams

“…Our model is based on two coupled equations for monochromatic fields of the fundamental and its second harmonic [5]. In the coupling terms we assumed perfect phase matching and the second order susceptibility, χ (2) , equal to 4 × 10 −12 m/V [30]. The corresponding numerical simulations, shown in Figs.…”

“…Introduction.-The preservation of wave packet phase, after the action of nonlinear or other phase deteriorating effects, is often referred to as "phase memory" [1][2][3]. Phase memory in general leads to a coherent wave packet behavior [1] while its physical origin is quite diverse ranging from quantum-mechanical physical system configurations [2,3], to optical wave packet distributions [1]. Optical wave packets that exhibit phase memory present exciting applications in strong field physics, like in higher harmonics and attosecond pulses [4].…”

“…where χ (2) is the nonlinear susceptibility. By using wellknown approximations of the Airy function [9] we reach to an analytical expression of the square of the Airy function term that appears in Eq.…”

“…where function [21]. Figure 1 shows a comparison Ai(ρ) 2 to the approximation Ai a 2 (ρ). Using the approximation of Eq.…”