Engineering J-aggregate cavity exciton-polariton devices

Abstract

Research efforts in solution-based dye lasers and organic light-emitting devices (OLEDs) have led to advances in materials engineering and fabrication technology, propelling the field of organic solid-state photonics. Active areas of photonic research in organic systems include solid-state lasers (in both VCSEL and DFB form factor), low-threshold optical switches, and photodetectors. In all of these areas, thin films of "Jelley aggregates," or J aggregates, offer a promising materials platform thanks to their narrow linewidth and high oscillator strength at room temperature, properties resulting from delocalization of excitations across multiple strongly-coupled molecules. By placing these films in an optical microcavity, the aggregates exhibit additional strong-coupling to the cavity electric field, creating light-matter quasi-particles known as exciton-polaritons, even at room temperature. In this thesis, I discuss my research on the properties of J-aggregate thin films and on advancing the device and materials engineering of strongly-coupled devices based on J-aggregate thin films to the level of those in inorganic semiconductor systems. Exciton-polariton systems have been extensively studied at cryogenic temperatures in II-VI and III-V semiconductor quantum well systems in the past two decades as potential low-threshold VCSELs.

(cont.) J-aggregate-based exciton-polaritons systems, however, offer many device and engineering challenges, including: understanding the role of inhomogeneous vs. homogeneous broadening in the J-aggregate optical response, fabricating higher-quality microcavities with the ability to pump the polaritons at high intensities, and lateral patterning on the single-micron scale of organic microcavities. These topics are addressed and the outlook of organic exciton-polariton device research discussed.