Radiative cooling using plasmon resonant nanostrips

Optical (far infrared) and thermal properties of a copper nanostrip array on silicon substrate were investigated. It acted as a coupler between the radiation and heat on the surface as nonradiative components (phonon or plasmon polariton at the surface), aiming to enhance outward heat flux from the surface as a cooling device via radiation heat transfer. The emission spectrum of the heat radiation was controlled by the nanostrip array that was designed as the local plasmon and phonon resonant conditions. In the experiment, it generated the temperature gradient of 1.3 K across the substrate thickness (0.5 mm) when the substrate was contacted on the heater (42°C) in the atmosphere at 26°C.