Optical properties of all-dielectric Fabry-Perot filter with Si-pillar-filled cavity

Employment of metasurfaces in interference optical filters yields additional flexibility to its design. Optical properties of such hybrid structures are ruled by the double nature of the interference effects occurring within... [ view full abstract ]

Employment of metasurfaces in interference optical filters yields additional flexibility to its design. Optical properties of such hybrid structures are ruled by the double nature of the interference effects occurring within the multilayer. While the planar layers may be described by conventional formalism of Fresnel coefficients, the included 3D nanostructures require application of full-wave Maxwell equation calculation, accounting for Mie scattering and/or possible plasmonic resonances induced in meta-atoms.
Single-cavity Fabry-Perot filter is one of the most known and widely used all-dielectric multilayer structures. Here we analytically investigate modification of this structure by inclusion of a metasurface of silicon pillars at the bottom of its cavity. We show how the geometry of the metasurface influences the optical properties of the device on terms of the transmission peak spectral position, the transmittance-at-peak value and the peak bandwidth value. The dependence of these parameters on the angle of incidence is also examined. Electric field profiles in the multilayers with different pillar geometries are drawn here as well.
We infer that the metasurface inclusion may serve as an instrument for fine tuning of the filter spectral characteristics. Their employment provides an important tool for micro-optics designers through enabling spatially local control of the optical performance of the filter. Additionally, some applications may gain from such hybrid structures thanks to dramatically lower concentration of light energy in the filter, and in particular in its cavity.
Electric file profiles in the multilayers with different pillar geometries are drawn here as well.
We infer that the metasurface inclusion may serve as an instrument for fine tuning of the filter spectral characteristics. Their employment provides an important tool for micro-optics designers through enabling spatially local control of the optical performance of the filter. Additionally, some applications may gain from such hybrid structures thanks to dramatically lower concentration of light energy in the filter, and in particular in its cavity.