Microsphere-coupled organic waveguides: Preparation, remote excitation of whispering gallery modes and waveguiding property

Rohit Chikkaraddy, Arindam Dasgupta, S. Dutta Gupta, G. V. Pavan Kumar

Research output: Contribution to journalArticlepeer-review


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.
How to efficiently transport light through one-dimensional micro and nanostructures? How can such structures be used for multiple optical functions? These are some of the important question in micro and nanophotonics, and a tremendous amount of research has been directed to answer such questions.1,2 In recent times, optical micro and nanostructures made of organic molecules have captured attention because they are versatile and flexible in nature.3–6 In the context of “green photonics,”7 organic nanostructure may play an important role in facilitating some building blocks of optical devices, including waveguiding property. Molecules that facilitate excitons can be harnessed to prepare one-dimensional waveguides. The transport of light in such molecular structures is assisted by exciton-polaritons, which are essentially coupled modes of electromagnetic waves and excitons.8,9 These collective excitations have interesting mode characteristics that can be excited beyond optical diffraction limit,10 and hence attractive candidates for nanophotonics.11–14
Original languageEnglish
JournalApplied Physics Letters
Publication statusPublished - 2013


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