Search

Enhancement of molecular emission is usually obtained by coupling small optical emitters with external resonant structures and systems, as first established by Purcell several decades ago, and verified in several recent investigations using molecules or quantum dots coupled with plasmonic nanoantennas. Here we theoretically investigate in detail a different mechanism for emission enhancement, based on our recent idea of a plasmonic nanolauncher [Phys. Rev. Lett. 2009, 103, 043902], i.e., a metamaterial-inspired ultranarrow waveguide channel operating near its cut-off frequency. Such system is not necessarily at resonance, but its peculiar operation may provide enhanced emission over a relatively broad physical area, which may allow enhancement of emission independent of the position of an individual or of a group of molecules along such plasmonic channel, and the possibility to bend and route the emitted energy with large flexibility. We present here extensive theoretical and numerical results that confirm this intuition and may envision a novel method for molecular emission enhancement at the nanoscale, with more flexibility than the conventional Purcell resonance techniques. [ABSTRACT FROM AUTHOR]

Alternating isotropic layers have been widely used in the design of acoustic cloaks to achieve the necessary anisotropy required by coordinate-transformation techniques. In this paper, this concept is expanded to plasmonic-type acoustic cloaking using a bilaminate shell consisting of two isotropic layers with uniform thickness. Explicit analytic expressions based on thin-shell approximations for the necessary cloaking layer properties are developed, facilitating an examination of the fundamental physical behavior and dominant design parameters for a bilaminate plasmonic-type acoustic cloak. Based on this analysis, the performance of a bilaminate plasmonic-type acoustic cloak is examined, and practical means of achieving the desired cloaking layer properties are discussed. [ABSTRACT FROM AUTHOR]