Dynamic MEMS-based optical metasurfaces

TL;DR

This paper introduces a novel electrically driven MEMS-based optical metasurface platform that enables dynamic, high-efficiency, broadband wavefront control for advanced optical applications.

Contribution

It combines a piezoelectric MEMS with a gap-surface plasmon OMS to achieve controllable phase and amplitude modulation, surpassing static metasurface limitations.

Findings

Achieved ~50% modulation efficiency

Demonstrated broadband operation (~20% near 800 nm)

Fast response time (<0.4 ms)

Abstract

Optical metasurfaces (OMSs) have shown unprecedented capabilities for versatile wavefront manipulations at the subwavelength scale, thus opening fascinating perspectives for next generation ultracompact optical devices and systems. However, to date, most well-established OMSs are static, featuring well-defined optical responses determined by OMS configurations set during their fabrication. Dynamic OMS configurations investigated so far by using controlled constituent materials or geometrical parameters often exhibit specific limitations and reduced reconfigurability. Here, by combining a thin-film piezoelectric micro-electro-mechanical system (MEMS) with a gap-surface plasmon based OMS, we develop an electrically driven dynamic MEMS-OMS platform that offers controllable phase and amplitude modulation of the reflected light by finely actuating the MEMS mirror. Using this platform, we demonstrate MEMS-OMS components for polarization-independent beam steering and two-dimensional focusing with high modulation efficiencies (~ 50%), broadband operation (~ 20% near the operating wavelength of 800 nm) and fast responses (< 0.4 ms). The developed MEMS-OMS platform offers flexible solutions for realizing complex dynamic 2D wavefront manipulations that could be used in reconfigurable and adaptive optical networks and systems.