Densely packed aluminum-silver nanohelices as an ultra-thin perfect light absorber

Abstract

Metals have been formed into nanostructures to absorb light with high efficiency through surface plasmon resonances. An ultra-thin plasmonic structure that exhibits strong absorption over wide ranges of wavelengths and angles of incidence is sought. In this work, a nearly perfect plasmonic nanostructure is fabricated using glancing angle deposition. The difference between the morphologies of obliquely deposited aluminum and silver nanohelices is exploited to form a novel three-dimensional structure, which is an aluminum-silver nanohelix array on a pattern-free substrate. With a thickness of only 470 nm, densely distributed nanohelices support rod-to-rod localized surface plasmons for broadband and polarization-independent light extinction. The extinctance remains high over wavelengths from 400 nm to 2000 nm and angles of incidence from 0° to 70°.

Bideposited silver nanocolloid arrays with strong plasmon-induced birefringence for SERS application

“…P-polarization and s-polarization refer to the direction of the oscillating electric field-along and perpendicular to the rods, respectively. The extinctance (E) is calculated through the equation E = 1 − R − T 17,18 . When silver nanorods are illuminated by an electromagnetic wave, p-polarized waves induce the longitudinal plasmonic mode and s-polarized waves induce the transverse plasmonic mode 19 .…”

Deposited ultra-thin titanium nitride nanorod array as a plasmonic near-perfect light absorber

“…The reflectance increases smoothly from = 400 nm to = 2000 nm at angles between θ = 40 • and θ = − 40 • . Unlike the p-polarized reflectance, the s-polarized reflectance has a minimum at angle of incidence 27,28 . The p-polarized extinctance has a high value of E = 78.1% at θ = − 60 • and = 685 nm ; in this direction, the electric field oscillates along the rods, inducing longitudinal plasmon resonance.…”

Tunable Plasmonic Resonances in TiN Nanorod Arrays

“…The finite-difference time-domain (FDTD) method is used to examine the variation of the localized field enhancement with the wavelength. High extinction of a nanostructured thin film indicates strong light coupling into the localized surface plasmon resonance [26]. The near field FDTD simulation was adopted to estimate the wavelength where strong local field intensity occurs and compare it with the far filed extinctance spectrum.…”