Optical Salisbury screen with design-tunable resonant absorption bands

Abstract

Growth of Au nanoparticle films and the effect of nanoparticle shape on plasmon peak wavelength A thin-film selective absorber at visible and near infra-red wavelengths is demonstrated. The structure consists of an optically thick layer of gold, a SiO 2 dielectric spacer and a partially transparent gold film on top. The optical cavity so formed traps and absorbs light at a resonance wavelength determined by the film thicknesses. Observed fundamental-resonance absorption strengths are in the range 93%-97%. The absorption red-shifts and broadens as the thickness of the top gold layer is decreased with little change in absorption strength. Thus, strong absorption with design-tunable wavelength and width is achieved easily by unstructured blanket depositions. Observed angle-dependent spectra agree well with the recent three-layer analytical model of Shu et al. [Opt. Express 21, 25307 (2013)], if effective medium approximation is used to calculate the permittivity of the top gold film when it becomes discontinuous at the lowest thicknesses. V C 2014 AIP Publishing LLC. [http://dx.

Far-infrared absorber based on standing-wave resonances in metal-dielectric-metal cavity

“…The band at 20 microns wavelength, which corresponds to secondary solutions for the λ(b,m) due to the strong dispersion of SiO 2 ,exists only for periods between 15 and 20 μm, before evidently blue-shifting out of the frame. This might be explained by a reduction in the effective index of the dielectric as the proportion of metal is decreased [38], which would decrease the resonance wavelength according to Eq. (4).…”

“…9 and widely reported by others. The mechanism proposed by Chen is similar to that used to describe Fabry-Perot type absorbers [43], such as the optical Salisbury screen [38].…”

Bilayer SiO2 Nanorod Arrays as Omnidirectional and Thermally Stable Antireflective Coating

“…One can attain zero reflectance condition at a specific wavelength when η 1 ¼ (η o η m ) 1/2 . [10,11] Different hybrid structures or their composites such as V 2 O 5 , SiC, SiO 2 , TiO 2 , MgF 2 , ZrO 2 , or Al 2 O 3 , are used for the fabrication of single-layer, bilayer or multilayer AR coatings. [4,8] Similarly, on a crown glass zero reflectance condition at 550 nm can be achieved by using a material having η ¼ 1.23 with a thickness of 112 nm.…”

Graphene-based optical absorbers

“…Up to now, different solutions based on the coherent perfect absorption (CPA) systems [3][4][5], onedimensional photonic crystals [6] and the Salisbury screen configuration [7][8][9][10], just to mention a few, have been proposed.…”