ABSTRACT
Thermal radiation spectrum can be designed using a perfect absorber based on a plasmonic metasurface, which is much thinner than the optical wavelength. Although many types of metasurface structures have been proposed over the past two decades, dynamic control of the thermal radiation spectrum remains challenging. A tunable metasurface with optical properties between perfect absorption and perfect reflection is required for adaptive thermal management. Active metasurfaces mediated by vanadium dioxide (VO2), a metal-insulator phase transition material, significantly bridge plasmonic and all-dielectric metasurfaces. In this chapter, the principle and metasurface structure for switchable absorptivity are described and subsequently demonstrated by including VO2 in a silicon metasurface. Switchable changes in absorptivity with respect to the transition temperature enabled us to achieve adaptive thermal radiation control for radiative cooling.
