Measurements of Radiative Properties of Engineered Micro/Nanostructures

Radiative properties of micro-/nanostructures can be very different from those of the corresponding bulk materials and are important for a variety of applications from energy harvesting, to biomolecular sensing and detection, manufacturing and materials processing, and thermal management in space and microelectronics. Novel micro-/nanostructured materials have continuously been developed along with the advancement in microfabrication and nanotechnology. Measurements of the far-field radiative properties, i.e., the absorptance, emittance, reflectance, and transmittance, are critically important in understanding the underlying mechanisms as well as testing the particular design structures. This chapter provides an overview of the recent advances in the development of several important micro-/nanostructures, their potential applications, and experimental results on their unique radiative properties. The following four representative nano-/microstructured materials are addressed with a focus on the experimental techniques and results. The first is grating/thin film hybrid structures in which magnetic polaritons can be excited for applications as coherence thermal emission sources and thermophotovoltaic emitters. The second is obliquely aligned Ag nanorod arrays with anisotropic optical and radiative properties. The third is vertically aligned carbon nanotube arrays that have a near-unity absorptance or emittance for radiometric application. The fourth is Si nanowires or nanocones with enhanced absorption and their application in solar cells.