Observation of three-dimensional discrete X-waves in femtosecond laser-written waveguide arrays

Abstract

In this paper, we report on the experimental observation of discrete X-waves in a two-dimensional waveguide array fabricated by femtosecond laser direct writing technique in fused silica. This type of optical wave spontaneously emerges from a compact pulse injected into a single site due to the interplay of the lattice's discrete diffraction as well as normal dispersion and focusing Kerr nonlinearity.