Translation of Nanoantenna Hot-Spots by a Metal-Dielectric Composite Superlens

We employ numerical simulations to show that highly localized, enhanced electromagnetic fields, also known as "hot spots," produced by a periodic array of silver nanoantennas can be spatially translated to the other side of a metal-dielectric composite superlens. The proposed translation of the hot spots enables surface-enhanced optical spectroscopy without the undesirable contact of molecules with metal, and thus it broadens and reinforces the potential applications of sensing based on field-enhanced fluorescence and surface-enhanced Raman scattering.Comment: 9 pages, 4 figure

Colloidal Plasmonic Titanium Nitride Nanoparticles: Properties and Applications

Optical properties of colloidal plasmonic titanium nitride nanoparticles are examined with an eye on their photothermal via transmission electron microscopy and optical transmittance measurements. Single crystal titanium nitride cubic nanoparticles with an average size of 50 nm exhibit plasmon resonance in the biological transparency window. With dimensions optimized for efficient cellular uptake, the nanoparticles demonstrate a high photothermal conversion efficiency. A self-passivating native oxide at the surface of the nanoparticles provides an additional degree of freedom for surface functionalization.Comment: 17 pages, 4 figures, 1 abstract figur

Trapped Rainbow Techniques for Spectroscopy on a Chip and Fluorescence Enhancement

We report on the experimental demonstration of the broadband "trapped rainbow" in the visible range using arrays of adiabatically tapered optical nano waveguides. Being a distinct case of the slow light phenomenon, the trapped rainbow effect could be applied to optical signal processing, and sensing in such applications as spectroscopy on a chip, and to providing enhanced light-matter interactions. As an example of the latter applications, we have fabricated a large area array of tapered nano-waveguides, which exhibit broadband "trapped rainbow" effect. Considerable fluorescence enhancement due to slow light behavior in the array has been observed.Comment: 15 pages, 4 figures, Published in Applied Physics

Plasmonic waveguides cladded by hyperbolic metamaterials

Strongly anisotropic media with hyperbolic dispersion can be used for claddings of plasmonic waveguides. In order to analyze the fundamental properties of such waveguides, we analytically study 1D waveguides arranged of a hyperbolic metamaterial (HMM) in a HMM-Insulator-HMM (HIH) structure. We show that hyperbolic metamaterial claddings give flexibility in designing the properties of HIH waveguides. Our comparative study on 1D plasmonic waveguides reveals that HIH-type waveguides can have a higher performance than MIM or IMI waveguides