Infrared-blocking plasmonic meta-glass for energy-saving passive windows.

Passive windows that can concurrently block infrared radiation while allowing transmission of visible radiation help in significantly reducing global energy usage by cooling and lighting systems deployed in buildings and vehicles. This Letter reports a design of plasmonic "meta-glass" that blocks up to ∼87% of infrared radiation over a spectral window of 750-1800 nm, predominantly responsible for indoor radiative heating, while maintaining an average visible transmission of 60% for providing indoor illumination. Our polarization-independent design comprises a two-dimensional hexagonal array of tungsten nanorings placed on top of a silica glass substrate. By virtue of surface plasmons excitation in the infrared regime, we achieve selective suppression in the transmission spectrum, which is tailorable by adjusting the dimension of the nanorings. The theoretically calculated figure-of-merit indicates that our proposed meta-glass designs outperform some of the recently reported window glass varieties in the literature.