# Temporal dynamics of light-written waveguides in unbiased liquid crystals

## TL;DR

This paper investigates the temporal formation dynamics of light-written waveguides in nematic liquid crystals, revealing that higher powers cause fluctuations and longer formation times due to self-steering effects.

## Contribution

It provides a theoretical analysis of the temporal dynamics of light-written waveguides in liquid crystals, highlighting the effects of spatial walk-off and nonlocality on formation time.

## Key findings

- Higher power induces beam fluctuations before stabilization.
- Longer formation times occur at increased power levels.
- Spatial walk-off influences waveguide formation dynamics.

## Abstract

The control of light by light is one of the main aims in modern photonics. In this context, a fundamental cornerstone is the realization of light-written waveguides in real time, resulting in all-optical reconfigurability of communication networks. Light-written waveguides are often associated with spatial solitons, that is, non-diffracting waves due to a nonlinear self-focusing effect in the harmonic regime. From an applicative point of view, it is important to establish the temporal dynamics for the formation of such light-written guides. Here we investigate theoretically the temporal dynamics in nematic liquid crystals, a material where spatial solitons can be induced using continuous wave (CW) lasers with few milliWatts power. We fully address the role of the spatial walk-off and the longitudinal nonlocality in the waveguide formation. We show that, for powers large enough to induce light self-steering, the beam undergoes several fluctuations before reaching the stationary regime, in turn leading to a much longer formation time for the light-written waveguide.