Far-infrared quasi-monochromatic perfect absorption in a thin GaAs film on gold

Abstract

We study the far-infrared absorption properties of a thin GaAs film on Au. We show that a 1.2-mu m GaAs film on Au can completely absorb an electromagnetic wave of 7.9 THz and totally reflect the waves of frequencies not very close to 7.9 THz. The uniformity of the layered structure enables observation of a quasi-monochromatic, nearly perfect absorption of 96% in a 1.4-mu m GaAs film. The absorption can be high for a wide range of incident angles. (C) 2015 Optical Society of America