Metal-based rugate filters with strong visible and near-infrared reflectivity

Abstract

Metallic rugate filters are theoretically investigated for the first time. Our model builds on randomly dispersed metallic nanorod arrays with sinusoidally varying porosities along the film thickness. It was found that metallic rugate filters can display strong optical response in the visible and near-infrared regions for both TE and TM polarizations and for a wide range of incident angles. Moreover, the optical features of a metallic rugate filter can be fine tuned by adjusting its structural features. Interestingly, multiplepeak rugate filters can be conveniently achieved by combining different periodicities in one rugate structure. The interesting optical behaviors of the novel metal-based reflectors, combined with the many desirable properties of metals (e.g. electric, thermal, magnetic, mechanical, and chemical properties) are bound to lead to various multi-functional optical devices.

Stacked Nanoporous Anodic Alumina Gradient-Index Filters with Tunable Multispectral Photonic Stopbands as Sensing Platforms

“…Photonic crystals (PCs) are a class of optical nanostructures with allowed and forbidden photonic bands that modify the movement of photons by altering the dispersion of electromagnetic waves when photons travel across the structure of PCs. These light–matter interactions can be tuned with accuracy by engineering the PCs’ structure, which features regularly distributed regions of high and low refractive index in one, two, or three dimensions. − PCs can be produced with different architectures and materials to attain light modulation across the broad range of spectral regions (from UV to IR), depending on the application needs. − …”

“…PCs modulate the flow of light when photons travel across the material. These light-matter interactions can be tuned with accuracy by engineering the PC´s structure, which features regularly distributed regions of high and low refractive index in one, two or three dimensions [8][9][10][11][12][13][14][15][16] . PCs can be produced with different architectures and materials to attain light modulation across the broad range of spectral regions (from UV to IR), depending on the application needs [17][18][19][20][21][22] .…”

Facile Fabrication of Porous Nickel Films with Tunable Colors

“…Theoretical studies have revealed that rugate structures made from heavily absorptive metals display weaker reflection features than those from metals of lower absorption. 28,29 Photonic crystal-based optical sensors offer the promise of low power consumption, high signal to noise ratio, and a broad refractive index sensing range. Various photonic crystal systems, such as porous silicon photonic structures, 5,20,30 inverse opal photonic crystals, 31 and photonic-crystal waveguides, 32,33 have been studied for their potential applications in optical sensors.…”