Liquid crystal-integrated metasurfaces for an active photonic platform

Abstract

Metasurfaces have opened the door to next-generation optical devices due to their ability to dramatically modulate electromagnetic waves at will using periodically arranged nanostructures. However, metasurfaces typically have static optical responses with fixed geometries of nanostructures, which poses challenges for implementing transition to technology by replacing conventional optical components. To solve this problem, liquid crystals (LCs) have been actively employed for designing tunable metasurfaces using their adjustable birefringent in real time. Here, we review recent studies on LCpowered tunable metasurfaces, which are categorized as wavefront tuning and spectral tuning. Compared to numerous reviews on tunable metasurfaces, this review intensively explores recent development of LC-integrated metasurfaces. At the end of this review, we briefly introduce the latest research trends on LC-powered metasurfaces and suggest further directions for improving LCs. We hope that this review will accelerate the development of new and innovative LC-powered devices.