Molecular Polaritons—Modulation, Impact on Chemistry and Modeling Their Density of States

Quantum emitters strongly coupled to optical cavity modes create new hybrid states called polaritons, resulting in a vacuum Rabi splitting (Ω). Strikingly, the magnitude of this splitting correlates with modified emission properties and chemical reaction rates. In this talk, I will discuss three important aspects of this phenomenon. First, active control of cavity coupling strength could enable on-demand modulation of cavity-modified materials properties. We demonstrate active tuning of excitonic strong coupling in a system where organic dyes strongly couple to propagating surface plasmon polaritons (SPPs) and modulation of vibrational strong coupling in a Fabry-Perot cavity coupled to an organic charge shuttling molecule. In both systems, strong coupling was effectively cycled on and off with electrode potential and were quantitatively correlated with simultaneously measured electrochemical charge. Next, I will discuss results indicating both enhanced and reduced chemical reaction rates for an alcoholysis addition reaction forming urethane monomers. Cavity tuning was used to selectively couple to reactant, solvent, and product vibrational modes resulting in distinct influences over chemical response. Lastly, and in light of the search for an understanding of the mechanisms leading to modified chemical and physical properties, I will present a theoretical description of the density of polariton states relative to molecular dark states. This work will also discuss the differences between polariton states generated in microcavities, slabs, and in the bulk.