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Enhancing the Purcell factor with graphene multilayers

Speaker: 
Ashley DaSilva (U. Texas at Austin, USA)
Date: 
Wed, 15/01/2014 - 11:00am to 12:00pm
Location: 
S13-M01-11 (Physics Conference Room)
Host: 
Shaffique Adam
Event Type: 
Seminars

Abstract

Graphene's response to electromagnetic excitation shows promise for a variety of applications including near perfect light absorption and radiative energy transfer control. At the heart of this response are collective oscillations of the carriers of graphene, which are known as plasmons. I will discuss the plasmon modes of weakly coupled graphene multilayers. These plasmon modes are associated with peaks in the transmission coefficient of electromagnetic waves. A radiative molecule placed near to the surface of such a graphene multilayer will radiate into these modes, thus decaying more rapidly, provided the energy of the radiated modes match the energy range of the plasmon modes. This ability to control radiative energy transfer is quantified by the Purcell factor, which is greatly enhanced in graphene multilayer systems in the THz to IR regimes of the electromagnetic spectrum. I will compare this behavior to that of metallic superlattices, which show enhanced Purcell factor in the optical part of the electromagnetic spectrum. Tuning the graphene Fermi level provides a knob with which to control the plasmon energies. This tunabilitiy as well as the novel energy regime (THz to IR) makes graphene multilayers an exciting system in which to study optical properties.

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