Experimental Demonstration of Phase Modulation and Motion Sensing Using Graphene-Integrated Metasurfaces

TL;DR

This paper demonstrates a graphene-integrated metasurface capable of dynamically modulating the phase and ellipticity of reflected light at mid-infrared wavelengths, enabling ultra-fast, tunable optical applications.

Contribution

It introduces a novel graphene-based metasurface that achieves significant, electrically controlled phase shifts and ellipticity modulation at mid-infrared wavelengths.

Findings

Reflection phase can be tuned up to 55 degrees.

Phase can be changed by 28 degrees with nearly constant amplitude.

Potential application in ultra-fast laser interferometry with sub-micron accuracy.

Abstract

Plasmonic metasurfaces are able to modify the wavefront by altering the light intensity, phase and polarization state. Active plasmonic metasurfaces would allow dynamic modulation of the wavefront which give rise to interesting application such as beam-steering, holograms and tunable waveplates. Graphene is an interesting material with dynamic property which can be controlled by electrical gating at an ultra-fast speed. We use a graphene-integrated metasurface to induce a tunable phase change to the wavefront. The metasurface supports a Fano resonance which produces high-quality resonances around 7.7 microns. The phase change is measured using a Michleson interferometry setup. It is shown that the reflection phase can change up to 55 degrees. In particular the phase can change by 28 degrees while the amplitude is nearly constant. The anisotropic optical response of the metasurface is used to modulate the ellipticity of the reflected wave in response to an incident field at 45 degree. We show a proof of concept application of our system in potentially ultra-fast laser interferometry with sub-micron accuracy.