Nanophotonics of Organic Molecular Waveguides: Towards Active Optical Antenna

Abstract

Photons resides at the heart of nanophotonics and controlling freely propagating photons at nanoscale is an important aspects in these applications. This effective control over optical field at nanoscale has relevance in all scientific domains such as optical communications, biomedical and quantum computing etc. All these nanophotonic applications bank on photons as an information carrier. At the same time, an additional challenge has appeared for practical realization of nanoscale information technology: how to effectively communicate the optical energy to other coupled nanostructures. In recent years, micro- and nanowire antenna have been investigated to explore this aspect, however most of these investigations are confined to plasmonic nanostructures. There are few concerns (heating and propagation loss, CMOS compatibility, efficiency and flexibility etc.) associated with conventional plasmonic materials therefore, organic nanostructures have been explored as an alternative candidates for photonic applications. To utilize organic nanostructures for signal processing devices both in active and passive domains, it is imperative to investigate directional emission of out-coupled photons. Additionally, it is vital to study the influence of plasmonic/dielectric coupling on directional emission of the individual organic nanostructures . To address all these issues, herein, we explore the directional emission from one dimensional organic nanostructures in different operational regime. We further extend our investigation on the influence of dielectric microstructure coupling for directing the out-coupled photon emission and demonstrate how to use dielectric microsphere as an active element for tuning the spectral feature of out-coupled photon. Moreover, we vertically couple organic nanowire (1D) with plasmonic substrate (2D) to efficiently channelling of exciton-polaritons to a leaky plasmonic substrate. Finally, we demonstrate the effect of near-field coupling on plasmons assisted directional emission.