Vortex beams with tunable "all-with-visible-light" dye-doped liquid crystal q-plates for broadband application

TL;DR

This paper presents a comprehensive analysis and experimental demonstration of dye-doped liquid crystal q-plates capable of generating broadband optical vortices with tunable properties using simple fabrication techniques.

Contribution

It introduces a novel approach for creating achromatic, tunable vortex-generating devices in the visible spectrum using dye-doped liquid crystal q-plates and a straightforward fabrication process.

Findings

Effective generation of high-quality optical vortices across the visible spectrum.

Diattenuation effects do not hinder device performance in broadband applications.

Simple fabrication method using commercial Variable Spiral Plate achieves tunable vortex generation.

Abstract

The photoalignment technique for liquid crystal (LC) device fabrication, despite being a well-established method, remains of significant relevance because of its broad applicability. Among its applications, one of particular interest is the generation of structured light, specifically the manufacturing of Pancharatman-Berry (PB) devices, capable of generating optical vortices with angular momentum. In this work, we propose a thorough theoretical and experimental analysis of the optical response of dye-doped liquid crystal (DDLC) devices by examining their performance in terms of tunability and achromaticity across the whole visible spectrum, considering diattenuation effects and how they affect the efficiency of the devices. We experimentally demonstrate the fabrication of photoaligned devices in the visible range with 532 nm laser light and the robust generation of high-quality optical vortices, achieved by a straightforward and accessible technique using a commercial Variable Spiral Plate (VSP), avoiding the need for complex rotational systems or programmable spatial light modulators. Our results demonstrate that diattenuation effects do not prevent the functionality of the devices across the whole visible spectrum and with extended ranges of achromaticity.