TE polarization selective absorber based on metal-dielectric grating structure for infrared frequencies

Abstract

The spectrum selective absorption effect in grating-based devices is studied. A TE polarization spectrum selective absorber exhibiting near 100% absorption at the resonant wavelength is investigated for infrared frequencies. A qualitative physical understanding of such perfect selective absorption effect is illustrated by investigating the electric field distributions and time-averaged power loss density. The influences of structure parameters on the absorption spectrum are studied in detail. Based on the study above, two multi-band absorbers with the vertically cascaded metal-dielectric grating structures are designed and investigated. The principle of such perfect absorption effects is attributed to guided mode resonance in different dielectric spacer layers. The designed absorber can be used in sub-diffraction-scale infrared pixels, high quality sensors and thermal emitters.