Photorefractive writing and probing of anisotropic linear and non-linear lattices

TL;DR

This paper experimentally investigates the writing and probing of anisotropic photorefractive lattices, analyzing their transient behavior, wave dynamics, and nonlinear phenomena like soliton formation, with results aligning well with theoretical predictions.

Contribution

It provides new experimental insights into the transient regime of photorefractive lattice writing and explores wave dynamics and nonlinear effects in these lattices.

Findings

Agreement between measurements and theory on drift-diffusion ratio

Observation of Bragg reflection and band structure in wave propagation

Detection of modulational instability and soliton formation

Abstract

We study experimentally the writing of one- and two-dimensional photorefractive lattices, focusing on the often overlooked transient regime. Our measurements agree well with theory, in particular concerning the ratio of the drift to diffusion terms. We then study the transverse dynamics of coherent waves propagating in the lattices, in a few novel and simple configurations. For focused linear waves with broad transverse spectrum, we remark that both the intensity distributions in real space ("discrete diffraction") and Fourier space ("Brillouin zone spectroscopy") reflect the Bragg planes and band structure. For non-linear waves, we observe modulational instability and discrete solitons formation in time domain. We discuss also the non-ideal effects inherent to the photo-induction technique : anisotropy, residual nonlinearity, diffusive term, non-stationarity.