Optical control is achieved on the excited state energy transfer between
spatially separated donor and acceptor molecules, both coupled to the same
optical mode of a cavity. The energy transfer occurs through the formed hybrid
polaritons and can be switched on and off by means of ultraviolet and visible
light. The control mechanism relies on a photochromic component used as donor,
whose absorption and emission properties can be varied reversibly through light
irradiation, whereas in-cavity hybridization with acceptors through polariton
states enables a 6-fold enhancement of acceptor/donor contribution to the
emission intensity with respect to a reference multilayer. These results pave
the way for synthesizing effective gating systems for the transport of energy
by light, relevant for light-harvesting and light-emitting devices, and for
photovoltaic cells.Comment: 52 pages, 40 Figures, 202