We investigate the optical properties of organic molecules (dyes) coupled to optical devices, aiming toward understanding quantum many-body processes in such hybrid systems and controlling these interactions. Gaining such control is important for photo-chemistry, light-harvesting and organic light-emitting devices.

While excitations in organic materials are localized on individual molecules, under strong light-molecule coupling, cavity polaritons are formed, with wave functions extending beyond the molecular scale. Using time-resolved microscopy we follow the motion of polaritons in real-time to show that this coupling induces long-range transport in organic materials and propagation over tens of microns.

Energy transfer between molecules is a process by which a donor molecule transmits its excitation energy to a nearby acceptor molecule. This can be a non-radiative process in which the excitation energy of a donor is directly transferred to an acceptor via dipole-dipole interaction, without the emission and reabsorption of free photons. By designing special metallic nanostructures in which plasmons are coupled to cavity photons, we can enhance the range of energy transfer from the typical nanometric range of Forster Resonant Energy Transfer (FRET) by one to two orders of magnitude, achieving energy transfer over distances which begin to approach the optical wavelength.

We study the scattering properties of molecules embedded in an optical cavity under strong coupling conditions, where the collective interaction between the molecules and the cavity gives rise to composite light−matter excitations known as cavity polaritons. The polaritonic states exhibit strong resonant Rayleigh scattering. The polaritonic wave functions in such systems are delocalized, corresponding to the collective scattering of each photon from a large ensemble of molecules.

Strong coupling with collective, inter-molecular vibrations occurring in organic materials in the low-terahertz region (≲1012 Hz). Using a cavity filled with α-lactose molecules, we take strong coupling into a new class of materials and processes, including skeletal polymer motions, protein dynamics, metal organic frameworks and other materials, in which collective, spatially extended degrees of freedom participate in the dynamics.