On the theory of frequency chirped pulse coherent amplification in inhomogeneously broadened gain medium

Abstract

Frequency chirped pulse interaction with inhomogeneously broadened two-level active medium when the pulse width is shorter than the homogeneous relaxation time T2 (coherent interaction) is studied theoretically. It is shown that, unlike the case of incoherent interaction when only half an energy stored can be converted into field, in the nonlinear coherent regime full extraction of active medium energy is possible. The analogy of the effect with Landau–Zener transition between crossing molecular curves is pointed out. Giving high-energy output at relatively low peak intensities, this nonlinear mechanism of energy extraction can be useful for excimer lasers.

New kinds of acoustic solitons

“…In this paper, we investigate the nonlinear dynamics of the acoustic extremely short pulses in the low-temperature paramagnetic crystal in the external magnetic field presence. In accordance with above-mentioned parallels between coherent optics and physical acoustics, we apply here the spectral overlap approximation [16]. This approximation is based on condition ε ≡ (ω 0 τ p ) 2 1,…”

Soliton mode of terahertz radiation generation using picosecond laser pulses with tilted wave fronts

“…In this regard, we note that a similar situation was considered in [30] when a terahertz signal was generated by the laser pulse with tilted wavefronts in the presence of multiphoton ionization. Note also that the nonlinear optics of unipolar pulses has been actively developing since the early 90s of the last century to the present day [4][5][6][31][32][33][34][35][36][37][38].…”

On the nonlinear optics of extremely short pulses

“…Here one should single out the theoretical works [24][25][26], in which both the SVE (3) approximation and the approximation of a low medium density (10) were not used. Instead of them, in the nonlinear optics of ESP, it was proposed to use the approximations of sudden perturbations (SPs)…”

“…As shown in [24], under condition (12) the ESP dynamics is described by an SG equation of the form (5). Only here, in contrast to QMP, the truncated " area" θ is the integral not of the envelope ψ, but of the electric field E of the pulse itself: θ ∼ t −∞ Edt ′ .…”

“…In contrast to (12), condition (13) corresponds to weak excitation of the medium and weak dispersion. In this case, the ESP dynamics is described by the modified Korteweg-de Vries (MKdV) equation [25,26]…”