Immobilization of photorefractive solitons by charge anchoring on conductive walls

Abstract

Spatial solitons have shown great promise for various applications, but their limited stability in terms of beam movement has been a significant hindrance. This limitation is especially prominent in the conventional configuration where the bias electric field is oriented perpendicular to the soliton propagation direction, leading to instability caused by the drift–diffusion processes. To address this issue, we explore a novel, to the best of our knowledge, approach where solitons are propagated from one bias plate to the other, with a tilted angle with respect to the field and to the optical axis of the photorefractive crystal. By directing the solitons toward the bias electrodes, we observe an intriguing anchoring effect that immobilizes the soliton beam, resulting in reduced self-bending. The charge distribution on the conductive walls is numerically investigated as a function of the crystallographic orientation of the c-axis. The immobilization of the soliton beams is a fundamental issue for their technological applications as waveguides in integrated photonic circuits, which would result in an addressable but perfectly stable waveguide over time.