Heat Radiation of Small Objects: Beyond Planck’s Equations

Objects that are smaller than the wavelength of thermal radiation cannot radiate heat efficiently. A generalized theory of thermal radiation has now been experimentally confirmed at the level of a single object at the Vienna University of Technology. All the objects around us emit thermal radiation. Usually, this radiation can be described very accurately using Planck's law. If, however, the radiating object is smaller than the thermal wavelength, it behaves according to different rules and cannot emit the energy efficiently. This has now been confirmed by a team of researchers at the Vienna University of Technology. These findings are important for heat management of nano-devices and also for the science of aerosols - microparticles suspended in air, which influence the climate.