This PDF file contains the front matter associated with SPIE Proceedings Volume 12199, including the Title Page, Copyright information, Table of Contents, and Conference Committee Page.

The strong coupling of cavity-confined photons and molecular electrons leads to the formation of hybrid light-matter states called cavity polaritons. While several groups have assessed the role of cavity polariton formation in important molecular photophysical processes, it remains unclear what resonator structures optimize control over ultrafast molecular dynamics and intermolecular interactions. In this talk, I will present results from our studies of cavity polariton formation and properties in multi-mode Fabry-Perot resonators loaded with porphyrin-based chromophores. For the first part of the presentation, I will discuss how changes in the structure of different multi-layer, multi-mode resonators affect the ultrafast radiative relaxation of copper (II) tetraphenylporphyrin. We show cavity polariton formation in the presence of strong, non-Condon vibronic coupling leads to the appearance of Lorentzian peaks in the photoluminescence spectra emitted by these samples. Using simple models, we show these features correspond to Herzberg-Teller (HT) polaritons, which possess deterministic characteristics consistent with our experimental data. In addition, we show how high-Q multimode cavities enhance coherent light emission from HT polaritons. For the second part of the talk, I will discuss our design, fabrication, and characterization of multi-layer, multi-mode Fabry-Perot resonators loaded with distinct porphyrin species. We show the near degeneracy of the electronic resonances of specific porphyrin pairs leads to the appearance of a middle polariton whose photonic content remains below 5%.

We present a study of photodegradation in functionalized anthraditiophene (diF TES-ADT)-based films in hybrid cavities composed of distributed Bragg reflector (DBR) bottom mirror and top silver (Ag) mirror, depending on two different DBR reflectivity stopbands. The concentration of diF TES-ADT was chosen such that the films contain molecules in “amorphous” and “aggregate” phases characterized by different optical absorption spectra. We demonstrate that the cavity photon preferentially couples to the molecules in the “amorphous” phase and observe different photodegradation, attributed to photodimerization, dynamics for cavity photon-coupled and uncoupled states. The presence of the longer lived emissive states, such as entangled triplet pair (TT) states formed in the process of singlet fission, was correlated with a faster photodimerization dynamics. The observed cavity-dependent photodimerization dynamics offers an opportunity to manipulate the reaction rates and yield with cavity characteristics.

Singlet fission and triplet-triplet annihilation have attracted much attention in recent years due to their potential application to organic photo devices. In both processes, triplet pairs are generated as an intermediate, which determined the efficiency of these processes. We have observed magnetic field effects on triplet pairs generated in organic crystals with magnetic fields up to 10 T. The trace of an exchange coupled triplet pair was found using a steady-state measurement. We determined the structure of the exchange coupled triplet pair together with the magnitude of the exchange interaction in the pair.