title: Plasmonic amplifiers: engineering giant light enhancements by tuning resonances in multiscale plasmonic nanostructures.
abstract: The unique ability of plasmonic nanostructures to guide, enhance, and manipulate subwavelength light offers multiple novel applications in chemical and biological sensing, imaging, and photonic microcircuitry. Here the reproducible, giant light amplification in multiscale plasmonic structures is demonstrated. These structures combine strongly coupled components of different dimensions and topologies that resonate at the same optical frequency. A light amplifier is constructed using a silver mirror carrying light-enhancing surface plasmons, dielectric gratings forming distributed Bragg cavities on top of the mirror, and gold nanoparticle arrays self-assembled into the grating grooves. By tuning the resonances of the individual components to the same frequency, multiple enhancement of the light intensity in the nanometer gaps between the particles is achieved. Using a monolayer of benzenethiol molecules on this structure, an average SERS enhancement factor <EF> ∼10⁸ is obtained, and the maximum enhancement in the interparticle hot-spots is ∼3 × 10¹⁰, in good agreement with FDTD calculations. The high enhancement factor, large density of well-ordered hot-spots, and good fidelity of the SERS signal make this design a promising platform for quantitative SERS sensing, optical detection, efficient solid state lighting, advanced photovoltaics, and other emerging photonic applications.
authors.affiliation: Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439, USA. aiqingchen@anl.gov
authors.forename: Aiqing
authors.initials: A
authors.lastname: Chen
authors.forename: Ryan L
authors.initials: RL
authors.lastname: Miller
authors.forename: A Eugene
authors.initials: AE
authors.lastname: DePrince
authors.forename: Alexandra
authors.initials: A
authors.lastname: Joshi-Imre
authors.forename: Elena
authors.initials: E
authors.lastname: Shevchenko
authors.forename: Leonidas E
authors.initials: LE
authors.lastname: Ocola
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Gray
authors.forename: Ulrich
authors.initials: U
authors.lastname: Welp
authors.forename: Vitalii K
authors.initials: VK
authors.lastname: Vlasko-Vlasov