Nearly Perfect Absorption by Bimetallic Surface Plasmonic Crystal and Its Application as Sensor

The author proposes and numerically investigates nearly perfect absorption in a bimetallic surface plasmonic crystal formed by two physically adjoined gold and silver nanohole array layers. The absorption over 99% at 650-nm wavelength is obtained and its high quality factor is preserved for oblique incidence. The structure is examined as a plasmonic sensor to measure the refractive indexes. The author achieves a very high modified figure-of-merit of 335.