Graphene Nanobubble: A New Optical Nonlinear Material

TL;DR

This paper demonstrates that graphene nanobubbles can serve as a new optical nonlinear medium, enabling fast all-optical switching and overcoming the interaction length limitations of atomically thin graphene in nonlinear optical devices.

Contribution

It introduces the use of graphene nanobubbles as a novel nonlinear optical material with enhanced phase change capabilities for digital optical applications.

Findings

Graphene nanobubbles exhibit strong nonlinear dispersive effects.

Optical bistability achieved within tens of nanoseconds.

Nanobubbles enable larger nonlinear effects than flat graphene layers.

Abstract

Graphene is a rising star in nonlinear optics due to its saturable absorption and giant Kerr nonlinearity, these properties are useful in digital optics based on optical nonlinear devices. However, practical applications require large optical nonlinearities and these are inherently limited by the interaction length of atomically thin graphene. Here, we demonstrate optical bistability in a Fabry Perot cavity containing monolayer and bilayer graphene which have been restructured to form nanobubbles. We find that graphene nanobubble can act as a new type of optical nonlinear media due to its vertical side wall as well as added curvature, which enable strong non linear dispersive effects leading to a large optically induced phase change. Unlike thermally induced bistability, the all optical switching between two transmission states happens within a time scale of tens of nanoseconds. Nanobubble based optical devices with intrinsic optical nonlinearity help to overcome the optical path length limitation of atomically thin two dimensional films and allow us to explore the promise of using such elements as the building block of digital all-optical circuitry.