Donor-Acceptor Energy Transfer in the Presence of Photonic and Plasmonic Structures

This proposal describes the development of new theories and computational methods for determining the rates of donor-acceptor energy transfer and related radiative processes associated with emitters and absorbers that are in the presence of complex dispersive optical structures, including semiconductor, dielectric and metallic nanoparticles, surfaces, and other photonic or plasmonic structures. There are a growing number of experiments where the complex optical environment plays an important role in energy transfer, sometimes enhancing energy transfer rates by many orders of magnitude and extending the range of energy transfer beyond the point where electrostatic interactions are adequate. In this situation, traditional Förster theory and standard improvements thereto are inadequate. Recently the Schatz group has developed a new approach to these problems, one that is fully quantum electrodynamic in nature but which only involves classical electrodynamics calculations for the optical response, making it possible to use existing computational electrodynamics methods with relatively simple modifications to calculate energy transfer rates. In addition, the method can be evaluated in the time domain, which is important in the treatment of complex structures, and allowing for the study of nonstationary donor and acceptor states where coherences and entangled states are excited. The proposal describes the development of theory that builds on this recent work, including (1) the proper incorporation of competing radiative and nonradiative processes in energy transfer, (2) the inclusion of donors and acceptors that are too large for point dipole approximations, (3) the treatment of dielectric response in the optical medium that goes beyond the standard Drude/Lorentz dielectric models, and (4) the description of energy transfer processes associated with coherent superpositions of quantum states, including coherences and entangled states. The proposal describes a number