Light and Sound in Three-Dimensional Graphene

January 18th, 2017 STEFANO LUPI Department of Physics
Sapienza University of Rome

2-Dimensional (2D) graphene emerged as an outstanding material for plasmonic and photonic applications due to its huge charge-density tunability, high electron mobility, and optical transparency. Recently, novel fabrication processes allowed to obtain three-dimensional (3D) structures based on high-quality monolayer graphene which provide a third dimension to this material.

Actually, many different 3D structures have been produced, spanning from 3D nanoporous graphene and nano-onions to 3D micro-network and nano-sponges, all retaining the unique characteristics of 2D graphene including massless Dirac fermions with high mobility. In this talk, after a brief review on the different 3D structures of graphene, I will focalize the discussion on nanoporous and sponge materials.

In nanoporous graphene, we reveal the presence of intrinsic 2D Dirac plasmons in the 3D structure disclosing strong plasmonic absorptions tunable from terahertz to mid-infrared via controllable doping level and porosity. The observed broad plasmon linewidths allow to cover most of the molecular mid-infrared fingerprint region with a single plasmon excitation paving the way for novel and competitive nanoporous-graphene based plasmonic-sensors.

In 3D aerogel sponge instead, we have shown that intensity modulated light can be transduced in acoustic waves through a photo thermal-acoustic mechanism. The unique combination of thermal, mechanical and electronic properties of graphene sheets arranged in the 3D sponge structure allows to achieve a high sound generation efficiency being practically independent of the light wavelength from radio waves to ultraviolet. The present results suggest that light-driven graphene-sponge based-devices could be widely used in a variety of new technological applications spanning from high-fidelity loudspeaker to radiation detectors.

Seminar, January 18, 2017, 12:00. ICFO’s Seminar Room

Hosted by Prof. Javier García de Abajo