Radiative Channeling of Nanowire Frenkel Exciton Polaritons through Surface Plasmons

Abstract

CommuniCation(1 of 6) 1600873 wave guiding [26] of light over millimeter length scale. Such long distance optical transport properties have been utilized for variety of nanophotonics applications such as optical logic gates, [27] resonators, [9,28] nanolasers, [26] photonic circuits, [12,28] etc.Interfacing organic molecular platforms with surface plasmons (SPs), [29][30][31] which are charge density oscillations at metal-dielectric interface, can provide excellent platform to study exciton-plasmon interaction at weak [32] and strong coupling [33,34] regimes. Interestingly, such coupling can also be harnessed for controlling light emission from organic nanostructures, [35] down to single photon limit. [36] A variety of schemes have been explored to interface excitonic systems with surface plasmons such as coupling of quantum dots with plasmonic substrate, [37] layered materials with plasmonic lattice, [38] core-shell nanoparticles, [33] molecular J-aggregates layer with plasmonic nanoparticles, [39,40] and photonic nanowire with gold nanoparticles. [36] These investigations are predominantly confined to probe energy transfer mechanism, recombination processes, [41] photoluminescence enhancement, [42] Rabi splitting, [43] generation of hybrid states, [44] biosensing applications, [45,46] and low-threshold nonlinear effects. [21] In many of these approaches, the dimensionality of the molecular material is either quasi 0D or quasi 2D in nature. So far, there are a few reports [47,48] on interfacing quasi 1D organic molecular systems, such as horizontally oriented nanowires with surface plasmons. [47,48] Alternately, we have recently introduced vertically oriented organic nanowire on a gold thin film. [49] Such a single, vertical nanowire provides a unique opportunity to study coupling of 1D propagating exciton polaritons with 2D propagating plasmon polaritons at nanoscale at a single point of contact. In this coupling scheme, an important issue to be addressed is the outcoupling of EP photoluminescence emission from a single, vertical nanowire into a specific direction through leaky plasmon channels of a gold film. Given that spontaneous emission is isotropic, there is an imperative to channel the nanowire emission, such that a majority of the light is collected and harnessed. Such directional outcoupling of emitted light has consequence on designing photovoltaic devices such as single-nanowire solar cells, [41,50,51] organic light emitting devices, [3,23] exciton-polariton lasers, [26] and nanooptical biosensors. [21,23] Here, we experimentally demonstrate directional, excitonpolariton photoluminescence emission channeled from a single, vertical organic nanowire through a plasmonic leaky channel of gold thin film. Figure 1 shows the conceptual schematic of the experiment. The tip of a vertically oriented organic semiconducting nanowire made of di-amino-anthraquinone (DAAQ) molecules is excited by a tightly focused laser beam at 532 nm wavelength. This excitation wavelength is close Hybrid nanophotonic devices compr...

Effects of spatial quantization and Rabi-shifted resonances in single and double excitation of quantum wells and wires induced by few-photon optical field

“…Such model is important in organic semiconducting nanowires which are of high interest in optoelectronic devices (see, e.g. [12]). To take into account the electron-electron interaction the dipole-dipole transfer of excitation between neighboring atoms is considered.…”