title: Mie resonance-enhanced light absorption in periodic silicon nanopillar arrays.
abstract: Mie-resonances in vertical, small aspect-ratio and subwavelength silicon nanopillars are investigated using visible bright-field µ-reflection measurements and Raman scattering. Pillar-to-pillar interactions were examined by comparing randomly to periodically arranged arrays with systematic variations in nanopillar diameter and array pitch. First- and second-order Mie resonances are observed in reflectance spectra as pronounced dips with minimum reflectances of several percent, suggesting an alternative approach to fabricating a perfect absorber. The resonant wavelengths shift approximately linearly with nanopillar diameter, which enables a simple empirical description of the resonance condition. In addition, resonances are also significantly affected by array density, with an overall oscillating blue shift as the pitch is reduced. Finite-element method and finite-difference time-domain simulations agree closely with experimental results and provide valuable insight into the nature of the dielectric resonance modes, including a surprisingly small influence of the substrate on resonance wavelength. To probe local fields within the Si nanopillars, µ-Raman scattering measurements were also conducted that confirm enhanced optical fields in the pillars when excited on-resonance.
authors: Francisco J
authors: FJ
authors: Bezares
authors: James P
authors: JP
authors: Long
authors: Orest J
authors: OJ
authors: Glembocki
authors: Junpeng
authors: J
authors: Guo
authors: Ronald W
authors: RW
authors: Rendell
authors: Richard
authors: R
authors: Kasica
authors: Loretta
authors: L
authors: Shirey
authors: Jeffrey C
authors: JC
authors: Owrutsky
authors: Joshua D
authors: JD
authors: Caldwell