Ultrafast All-optical control of Multiple Light Degrees of Freedom through Mode-mixing in a Graphene Nanoribbon Metamaterial

TL;DR

This paper introduces a dual-stack graphene nanoribbon metamaterial enabling ultrafast, broadband control over multiple light properties such as amplitude, phase, polarization, and angular momentum through independent mode-mixing layers.

Contribution

It presents a novel design for a metamaterial that achieves dynamic, selective control of multiple light degrees of freedom using graphene's tunable optical properties.

Findings

Achieves broadband ultrafast control over light's properties.

Demonstrates independent control of two nanoribbon layers.

Enables high-speed, high-data-rate optical modulation.

Abstract

The evolution of optical technologies necessitates advanced solutions for selective and dynamic manipulation of light's degrees of freedom, including amplitude, phase, polarization, wavelength, and angular momentum. Metamaterials can offer such control through the interplay between the intrinsic material and geometrical properties of nanostructures or extrinsically through excitation and detection symmetry breaking, leading to customizable performance. However, achieving dynamic control over multiple light degrees of freedom remains a challenge. To address existing limitations, we present a novel dual-stack metamaterial design capable of broadband ultrafast control over amplitude, phase, polarization, spin angular momentum, and handedness of light mediated by two independently controlled nanoribbon layers that enable flexible and selective mode-mixing in both reflection and transmission. Through a combination of a thermal response model and Finite-Difference Time-Domain simulations, we investigate graphene as a suitable material for the metamaterial design, leveraging the intrinsic optical properties of graphene and its tunable conductivity through electrostatic gating and ultrafast optical excitation, achieving selective control over multiple light degrees of freedom at ultrafast timescales. This selective ultrafast mode-mixing significantly advances the capabilities of high-speed photonic systems, paving the way for compact, high data-rate optical technologies essential for future applications.