Temperature of a nanoparticle above a substrate under radiative heating and cooling

Controlling the temperature in architectures involving nanoparticles and substrates is a key issue for applications involving micro and nanoscale heat transfer. We study the thermal behavior of a single nanoparticle interacting with a flat substrate under external monochromatic illumination, and with thermal radiation as the unique heat loss channel. We develop a model to compute the temperature of the nanoparticle, based on an effective dipole-polarizability approach. Using numerical simulations, we thoroughly investigate the impacts of various parameters affecting the nanoparticle temperature, such as the nanoparticle-to-substrate gap distance, the incident light wavelength and polarization, or the material resonances. This study provides a tool for the thermal characterization and design of micro or nanoscale systems coupling substrates with nanoparticles or optical antennas.