General in situ feedback control of cascaded liquid crystal spatial light modulators for structured field generation

TL;DR

This paper introduces a real-time, in situ feedback control method for cascaded liquid crystal spatial light modulators, improving structured light and matter field generation by compensating for experimental imperfections dynamically.

Contribution

The authors develop a physically informed, manifold-constrained gradient-descent control scheme enabling real-time error correction without modifying the experimental setup.

Findings

Effective correction of optical aberrations demonstrated

Enhanced stability of structured fields over time shown

Method applicable to complex vectorial aberrations

Abstract

Cascaded liquid crystal spatial light modulators provide a versatile strategy for the generation of structured light and matter fields, with applications including optical communications, photonic computing, and topological field engineering. However, experimental imperfections, such as temperature-dependent liquid crystal response, variations between individual pixels, and alignment errors, present significant engineering challenges in generating high-quality fields. Moreover, changes in experimental conditions over time mean that calibrating each component once is insufficient for maintaining long-term, high-quality field generation. To address this, we present a general engineering approach based on a bespoke, physically informed, and manifold-constrained gradient-descent scheme that enables in situ feedback control, compensating for such errors in real time without the need to alter the experimental setup. We further demonstrate the correction efficacy of our proposed strategy through experiments in both spatially varying light and matter field generation, including scenarios in which complex vectorial aberrations are artificially introduced into the setup. Together, these demonstrations underscore the practicality of our method and its suitability for deployment in real-world experimental environments, paving the way for robust operation of cascaded architectures for structured field generation.