Program
Physics and Astronomy
College
Arts and Sciences
Student Level
Doctoral
Start Date
7-11-2019 2:00 PM
End Date
7-11-2019 3:45 PM
Abstract
Radiative heat transfer is the mechanism by which objects, in absence of conduction and convection, reach thermal equilibrium with one another and their environment. This process involves the emission of photons whose wavelengths are determined by the temperature of the object, and is, at the macroscale, accurately described by Planck's law. However, when the dimensions of an object, or the distance separating it from others, is smaller than the thermal wavelength, this law breaks down; contributions from near-field modes, augmented by the presence of optical resonances, can produce drastically different emission spectra. A specific material that is of great interest to exploit this phenomenon is graphene, a two-dimensional material composed of carbon atoms in a honeycomb lattice. This is because it can be doped to support surface plasmons, the collective oscillations of conduction electrons, in the mid-infrared part of the spectrum, which is the most relevant set of wavelengths for radiative heat transfer at conventional temperatures. In addition, the plasmons supported by graphene are actively tunable, enabling real-time manipulation of the radiative transfer between neighboring nanostructures. Here, we exploit these extraordinary properties to study the time dynamics of the radiative transfer between graphene nanodisks and achieve new heat transfer scenarios relying on active control. These results serve both to advance fundamental understanding of near-field radiative heat transfer, and also to inspire the development of new thermophotovoltaic devices, thermal management techniques, and other technologies relying on the nanoscale manipulation of energy.
Temporal Control Over the Radiative Heat Transfer Between Graphene Nanodisks
Radiative heat transfer is the mechanism by which objects, in absence of conduction and convection, reach thermal equilibrium with one another and their environment. This process involves the emission of photons whose wavelengths are determined by the temperature of the object, and is, at the macroscale, accurately described by Planck's law. However, when the dimensions of an object, or the distance separating it from others, is smaller than the thermal wavelength, this law breaks down; contributions from near-field modes, augmented by the presence of optical resonances, can produce drastically different emission spectra. A specific material that is of great interest to exploit this phenomenon is graphene, a two-dimensional material composed of carbon atoms in a honeycomb lattice. This is because it can be doped to support surface plasmons, the collective oscillations of conduction electrons, in the mid-infrared part of the spectrum, which is the most relevant set of wavelengths for radiative heat transfer at conventional temperatures. In addition, the plasmons supported by graphene are actively tunable, enabling real-time manipulation of the radiative transfer between neighboring nanostructures. Here, we exploit these extraordinary properties to study the time dynamics of the radiative transfer between graphene nanodisks and achieve new heat transfer scenarios relying on active control. These results serve both to advance fundamental understanding of near-field radiative heat transfer, and also to inspire the development of new thermophotovoltaic devices, thermal management techniques, and other technologies relying on the nanoscale manipulation of energy.
