Ultrathin 2 nm gold as impedance-matched absorber for infrared light

Abstract

Long-term stability and broad spectral response are highly desired features of absorbers. Here, the authors report impedance matched absorbers based on 2 nm thick gold layer operating within the mid-infrared range from 2 to 20 μm, enabling stable long term absorptivity of 47(3) % which is mostly wavelength independent.