Enhanced and near-unidirectional thermal emission based on cascaded particle phonon-polaritons (PhPs)

Micron-scale objects made of semiconductors can support highly localized photonic modes in the reststrahlen band regime known as particle or Mie phonon-polaritons (PhPs). We will discuss how these particle PhPs can serve as building blocks to construct platforms with enhanced near-unidirectional thermal emission that is directed to the upper hemisphere only. These systems are highly relevant to current applications such as the development of long-wavelength infrared (LWIR) sources, thermal photovoltaics and passive radiative cooling.