Control of spatial four wave mixing efficiency in Bessel beams using longitudinal intensity shaping

TL;DR

This paper explores how shaping the spatial spectral phase of Bessel beams can control four wave mixing efficiency, reducing nonlinear instabilities and enabling better management of ultrashort pulse propagation in nonlinear media.

Contribution

It introduces a method to control nonlinear instabilities in Bessel beams by shaping their spectral phase, advancing the manipulation of nonlinear optical processes.

Findings

Spectral phase shaping suppresses nonlinear frequency growth.

Control of four wave mixing enhances beam stability.

Potential applications in material processing and ultrashort pulse management.

Abstract

Diffraction-free Bessel beams have attracted major interest because of their stability even in regimes of nonlinear propagation and filamentation. However, Kerr nonlinear couplings are known to induce significant longitudinal intensity modulation, detrimental to the generation of uniform plasma or for applications in the processing of transparent materials. These nonlinear instabilities arise from the generation of new spatio-spectral components through an initial stage of continuous spectral broadening followed by four wave mixing. In this paper, we investigate analytically and numerically these processes and show that nonlinear instabilities can be controlled through shaping the spatial spectral phase of the input beam. This opens new routes for suppressing the nonlinear growth of new frequencies and controlling ultrashort pulse propagation in dielectrics.