LIGHT ABSORBER WITH AN ULTRA-BROAD FLAT BAND BASED ON MULTI-SIZED SLOW-WAVE HYPERBOLIC METAMATERIAL THIN-FILMS (Invited Paper)

Here we realize a broadband absorber by using a hyperbolic metamaterial composed of alternating aluminum-alumina thin fllms based on superposition of multiple slow-wave modes. Our super absorber ensures broadband and polarization-insensitive light absorption over almost the entire solar spectrum, near-infrared and short-wavelength infrared regime (500{2500nm) with a simulated absorption of over 90%. The designed structure is fabricated and the measured results are given. This absorber yields an average measured absorption of 85% in the spectrum ranging from 500nm to 2300nm. The proposed absorbers open an avenue towards realizing thermal emission and energy- harvesting materials.