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We report on angle-resolved, exciton-polariton photoluminescence measurements from asymmetric terminals of a microsphere-coupled organic waveguide (MOW). The MOW architecture consisted of a SiO2 microsphere coupled with a diaminoanthroquinone mesowire, self-assembled on a glass substrate. The angle-resolved emission measurements were performed using spatially filtered Fourier-plane optical imaging method. The light emanating from the sphere-terminus had two regions of angular emission in the Fourier-plane, of which one had azimuthal angular spread as small as 10°. The emission from wire terminus was uni-directional in nature, with some light emitted beyond the critical angle of glass-air interface. Our results highlight unique directional emission characteristics of a hybrid organic waveguide geometry and may have implications on single-element, exciton-polariton based light-emitting devices and lasers.

We demonstrate how a silver-nanowire-dimer can be employed to optically excite dual-path surface-plasmon-polaritons and utilize them to perform remote-excitation surface-enhanced Raman scattering (SERS) microscopy. Interestingly, this unique geometry allows us to perform dual-path remote-excitation SERS. Our experiments show that for the same value of excitation-laser powers, dual-path excitation leads to enhanced-SERS signal compared to single-path excitation, which has been corroborated by 3-D finite-difference time-domain simulations. Furthermore, we show that SERS-enhancement can be remotely modulated in this geometry by varying the polarization of excitation-fields. The results discussed herein can be extrapolated to remote-excitation pump-probe spectroscopy and dual-colour optical interrogation.

In this letter, we show how organic molecular waveguides of 1,5-diaminoanthraquinone molecules can be grown on a silica microsphere to obtain microsphere-coupled organic waveguides (MOWs). Using such MOWs, we remotely excite and detect whispering gallery modes (WGMs) of the attached microsphere. Interestingly, these WGMs showed mode-splitting and mode-mixing due to broken azimuthal symmetry of the microsphere. Furthermore, the waveguiding characteristics of MOWs showed a quadrupole intensity pattern as a function of input polarization. The presented geometry can be an excellent test-bed to study fundamental aspects of coupled resonant systems, and their properties can be harnessed in nano- and bio-photonics.