Cooperative Energy Transfer in Plasmonic Systems

Vitaliy N. Pustovit Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio, USA Augustine M. Urbas Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio, USA Tigran V. Shahbazyan Department of Physics, Jackson State University, Jackson, Mississippi, USA

Forster’s energy transfer [1] between donor and acceptor fluorophores, e.g., dye molecules or semiconductor quantum dots, underpins diverse phenomena in biology, chemistry and physics [2]. While Forster’s transfer between isolated fluorophores is efficient only for relatively short donor-acceptor separations below 10 nm, plasmon-mediated transfer channels available near metal nanostructures lead to significant increase of energy transfer rate for larger donor-acceptor distances [3]. The fraction of the donor energy absorbed by the acceptor is determined by the interplay between transfer, radiation and dissipation channels, so that an increase of energy transfer efficiency implies either increase of the transfer rate or reduction of the dissipation and/or radiation rates.

Here we describe a cooperative amplification mechanism for energy transfer from a large ensemble of donors to fewer acceptors that takes advantage of a subtle balance between energy flow channels in a plasmonic system. Namely, if donors’ are not too close to the metal surface then the plasmonic coupling between donors’ gives rise to robust superradiant and subradiant states [4]. In this case, energy transfer to an acceptor takes place from these collective states rather than from many individual donors [5]. We show that energy transfer efficiency from donors’ superradiant states to an acceptor is significantly amplified relative to that from the same number of individual donors due to the large matrix element of superradiant states with acceptor’s electric field. At the same time, energy transfer from subradiant states to an acceptor is amplified as well due to their reduced Ohmic and radiative losses.

[1] T. Forster, Ann. Phys. 437, 55 (1948).

[2] J. R. Lakowicz, Principles of Fluorescence Spectroscopy, (Springer, New York, 2006).

[3] P. Andrew and W. L. Barnes, Science 306, 1002 (2004).

[4] V. N. Pustovit and T. V. Shahbazyan, Phys. Rev. Lett. 102, 077401 (2009).

[5] V. N. Pustovit, A. M. Urbas, and T. V. Shahbazyan, Phys. Rev. B 88, 245427 (2013).

shahbazyan@jsums.edu









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