May 21, 2020

Our last publication Active temporal control of radiative heat transfer with graphene nanodisks has appeared in Physical Review Applied.

The ability to dynamically control the radiative transfer of heat at the nanoscale holds the key to the development of a diverse number of technologies, ranging from nanoscale thermal-management systems to improved thermophotovoltaic devices. Recently, graphene has emerged as an ideal material to achieve this goal, since it can be electrically doped to support surface plasmons, collective oscillations of the conduction electrons. These resonances produce large and spectrally narrow optical cross sections, which dictate the emission and absorption properties of the graphene nanostructure and, thus, the heat that it radiatively exchanges with other objects and the environment. For attainable levels of doping, the plasmons supported by graphene nanostructures naturally lie in the midinfrared part of the spectrum, which is the most relevant wavelength range for radiative heat transfer under realistic temperatures. Furthermore, these resonances are actively tunable, thus providing full dynamic control over the heat transfer. Motivated by this great potential, we present a comprehensive analysis of the temporal evolution of the radiative heat transfer between arrangements of graphene nanodisks, showing that it is possible to exploit the tunability of these structures to obtain actively controlled heat transfer scenarios not possible with conventional passive nanostructures. The results of this work provide a framework for achieving fully dynamical control over nanoscale radiative heat transfer and thus provide fundamental insights into this process.

April 8, 2020

We are very happy to receive an NSF Career Award for a project entitled: Transfer of Momentum and Energy in the Nanoscale Using Quantum and Thermal Fluctuations.

The interaction between light and matter in the nanoscale can be very different from our daily macroscopic experience. When the dimensions of material structures, or the space separating them, reach the range of nanometers, the quantum nature of light and matter emerges, giving rise to new phenomena. In that limit, Casimir interactions, which arise from quantum and thermal fluctuations of the electromagnetic field, play a dominant role and can overcome other interactions, such as gravitational forces, thus conditioning the dynamics of nanoscale objects. The fluctuations of the electromagnetic field are also at the origin of the radiative transfer of energy between bodies at different temperatures. In this context, and thanks to the enormous advances in nanofabrication technologies, we have reached the limit in which the effects caused by the quantum and thermal fluctuations of the electromagnetic field have important consequences for the mechanical and thermal dynamics of nanostructures. This has posed new challenges for the development of applications in nanotechnology. However, it also constitutes a unique opportunity to develop new approaches to manipulate the mechanical and thermal dynamics of nanostructures. In this project, we will tackle this research challenge by investigating the transfer of momentum and energy between nanoscale objects within the context of two novel concepts that have recently emerged in nanophotonics: structures with atomic thickness and spin-orbit interactions of light. The investigation of these phenomena within a common theoretical framework will allow us to establish the foundations for new paradigms enabling noncontact transfer of momentum and energy in the nanoscale, which can help to develop novel approaches to manipulate nanoscale objects, including biologically relevant structures. Furthermore, the results on the energy transfer will have an impact on the improvement of thermophotovoltaic devices and heat management strategies in nanoelectronics. At the same time, this project will be an opportunity to improve the recruitment and retention of STEM students, which is one of the most important structural problems that education in New Mexico currently faces, with a special emphasis on targeting first-generation and low-income students from underrepresented minorities. To that end, we will implement a range of activities targeting students from middle school to the graduate level, which aim to build interest in STEM disciplines, preserve that interest, and mold it into essential skills and experience