All-Optical tunability of metalenses infiltrated with liquid crystals

TL;DR

This paper demonstrates an all-optical, reconfigurable metalens embedded with liquid crystals, enabling dynamic focal length tuning through thermo-plasmonic effects without mechanical or electrical adjustments.

Contribution

It introduces a novel liquid crystal infiltrated metalens with all-optical tunability, allowing reversible focal length control via thermo-plasmonic effects.

Findings

Achieved 80 μm reversible focal length tuning

Demonstrated control through thermo-plasmonic phase transition

Numerical simulations closely match experimental results

Abstract

Metasurfaces have been extensively engineered to produce a wide range of optical phenomena, allowing unprecedented control over the propagation of light. However, they are generally designed as single-purpose devices without a modifiable post-fabrication optical response, which can be a limitation to real-world applications. In this work, we report a nanostructured planar fused silica metalens permeated with a nematic liquid crystal (NLC) and gold nanoparticle solution. The physical properties of embedded NLCs can be manipulated with the application of external stimuli, enabling reconfigurable optical metasurfaces. We report all-optical, dynamic control of the metalens optical response resulting from thermo-plasmonic induced changes of the NLC solution associated with the nematic-isotropic phase transition. A continuous and reversible tuning of the metalens focal length is experimentally demonstrated, with a variation of 80 um (0.16% of the 5 cm nominal focal length) along the optical axis. This is achieved without direct mechanical or electrical manipulation of the device. The reconfigurable properties are compared with corroborating numerical simulations of the focal length shift and exhibit close correspondence.