Laser beam deflector based generation of few-cycle electromagnetic pulses in a circular nonlinear medium

Abstract

We study theoretically a novel possibility for the emission of few-cycle pulses via excitation of nonlinear oscillators arranged in a thin circular string by a spot of light moving along the string. Such excitation can be realized by a beam emitted from a source at some distance, when the beam rotates with high constant angular velocity. Here we analyze the possibility to realize such setup using ultrafast beam deflectors and a diffractive optical element (DOE). We show that the pulse duration, amplitude and spectrum can be controlled by the spot velocity, the resonance frequency of the medium as well as by the parameters of the DOE. Remarkably, the electric field area of the generated field does not depend on DOE characteristics. These theoretical predictions open novel opportunities in generation of few cycle pulses with controllable duration and waveshape.