Deep optical penetration dynamics in photo-bending

TL;DR

This paper models the behavior of photo-sensitive liquid crystalline sheets under illumination, revealing how light penetration dynamics influence tilt, curvature, and phenomena like overshoot and eclipsing, with implications for understanding photo-bending.

Contribution

It introduces a model capturing both stationary and dynamic responses of photo-sensitive sheets, emphasizing the role of light penetration fronts and eclipsing phenomena.

Findings

Maximum curvature occurs at the sheet's middle under intense light.

Overshoot and self-eclipsing phenomena are observed in the dynamics.

Eclipsing behavior aligns qualitatively with previous experiments.

Abstract

We model both the photo-stationary state and dynamics of an illuminated, photo-sensitive, glassy liquid crystalline sheet. To illustrate the interplay between local tilt $\theta$ of the sheet, effective incident intensity, curvature and dynamics, we adopt the simplest variation of local incident light intensity with angle, that is $\cos\theta$. The tilt in the stationary state never overshoots the vertical, but maximum curvature could be seen in the middle of the sheet for intense light. In dynamics, overshoot and self-eclipsing arise, revealing how important moving fronts of light penetration are. Eclipsing is qualitatively as in the experiments of Ikeda and Yu (2003).