# Electrically Tunable Optofluidic Metasurface

## TL;DR

This paper introduces a new type of metasurface that can be tuned with electricity and fluids, allowing precise control of light at the nanoscale.

## Contribution

The novel contribution is an all-dielectric optofluidic metasurface with low-voltage, high-efficiency tuning of light.

## Key findings

- The metasurface achieves a near-2π phase shift with a low voltage swing of ±3 V.
- It maintains strong resonance amplitude (R > 80%) using an all-pass filter configuration.

## Abstract

The dynamic control of light at the nanoscale has been
a longstanding
challenge in photonics. More recently, fluidics has been added to
the toolkit, leveraging liquid properties as an additional degree
of freedom for tunability. Here, we present a tunable metasurface
architecture that integrates an optofluidic layer. We use a guided
mode resonance platform, whereby a silicon nitride grating is coated
with indium tin oxide (ITO) as the active material, operating in the
visible-NIR wavelength range (∼800 nm). Our design employs
an all-dielectric structure with a fluidic gate to overcome the efficiency-loss
trade-off typical of other dynamic metasurfaces. We demonstrate spectral
and phase tuning, achieving a near-2π phase shift with a low
voltage swing (±3 V), as well as maintaining a strong resonance
amplitude (R > 80%) with an all-pass filter configuration.
These results establish a foundation for high-performance tunable
metasurfaces with broad cross-disciplinary applications.