Ultrashort Pulses in Metamaterial and Plasmonic Structures

Abstract

Electromagnetic spin-dipole and magnetostatic (spin-dipole) extremely short pulses in ferrite films are considered. The methods of nonlinear evolution equations (for waves) in layered structures (NEELS) and of Vainshtein equivalent nonlinear sources (VENS) form the basis for the corresponding modeling. Higher-order nonlinear equations for extremely short GHz pulses in ferrite films are reconsidered, and an important extra term describing self-steepening effect for the magnetostatic waves is found. The evolution of bullets (spatio-temporal nonlinear pulses/solitons, strongly localized in two dimensions) and collapsing pulses in ferrite and metamaterial (plasmonic) waveguides, accounting for higherorder linear and nonlinear effects, is modeled. The combined effect of linear and nonlinear diffraction and dispersion on the propagation and nonlinear instability of the bullets is found and investigated. The conditions, when the collapse of nonlinear spin-dipole waves of the millimeter wave range is possible, are found. Ultra-short baseband pulses in ferroelectrics and effect of 2D ultra compression in the linear lensing and nonlinear focusing-defocusing media are searched. It is possible to realize the propagation of baseband bright pulses and an analog of modulation instability for relatively long (10–20) ps input baseband pulses, without any carrier frequency. Due to modulation instability, it is possible to form the regular sequences of envelope pulses shorter than 5 ps at the carrier frequencies (0.4 - 0.8) THz. The baseband ultrashort pulses without a carrier frequency possess the durations less than 1 ps.