Infrared (IR) Absorber Based on Multiresonant Structure

In this letter, an absorber design is introduced that has a very wide absorption band at normal incidence over the midrange infrared (IR) wavelength regime. The proposed structure is comprises four layers, where the extra layer adds a degree of freedom in optimizing the response compared the conventional three-layered absorbers (dielectric spacer sandwiched between a ground thin film and a resonant conducting pattern). The simulations revealed a broadband absorption region that extends from 3 up to 12 mu m of light wavelength achieving more than 120% of full bandwidth at half-maximum (FWHM).