Dynamic control of Förster energy transfer in a photonic environment

Abstract

In this study, the effect of modified optical density of states on the rate of Förster resonant energy transfer between two closely-spaced chromophores is investigated. A model based on a system of coupled rate equations is derived to predict the influence of the environment on the molecular system. Due to the near-field character of Förster transfer, the corresponding rate constant is shown to be nearly independent of the optical mode density. An optical resonator can, however, effectively modify the donor and acceptor populations, leading to a dramatic change in the Förster transfer rate. Single-molecule measurements on the autofluorescent protein DsRed using a λ/2-microresonator are presented and compared to the theoretical model's predictions. The observed resonator-induced dequenching of the donor subunit in DsRed is accurately reproduced by the model, allowing a direct measurement of the Förster transfer rate in this otherwise inseparable multichromophoric system. With this accurate yet simple theoretical framework, new experiments can be conceived to measure normally obscured energy transfer channels in complex coupled quantum systems, e.g. in photovoltaics or light harvesting complexes.

FRET Enhancement in Aluminum Zero‐Mode Waveguides

“…3b). For short D-A distances (on the order of the Förster radius or below), the direct dipole-dipole energy transfer dominates and the LDOS has a moderate effect on the FRET rate, especially for nanophotonic structures of the size of a half wavelength with limited field gradients [31]. However, for larger D-A distances and structures with more pronounced field confinement, a supplementary contribution from the energy transfer mediated by the nanostructure can further enhance the apparent FRET rate [24,48].…”

“…Several earlier works have considered the influence of photonic nanostructures on the FRET process: some conclude that the FRET rate depends linearly on the donor emission rate and the LDOS [23][24][25][26][27], while some others report a FRET rate independent of the LDOS [28][29][30][31]. Earlier experiments on aluminum C-shaped nanoapertures did not reveal noticeable changes of the FRET efficiency [32].…”

Vorschau 11/2014

“…Another remarkable feature of FRET in ZMWs is the larger FRET rate enhancement in the case of increased D –A separations (Figure 3b). For short D –A distances (of the order of the Förster radius or below), the direct dipole–dipole energy transfer dominates and the LDOS has a moderate effect on the FRET rate, especially for nanophotonic structures of the size of a half‐wavelength with limited field gradients 31. However, for larger D –A distances and structures with more pronounced field confinement, a supplementary contribution from the energy transfer mediated by the nanostructure can further enhance the apparent FRET rate 24.…”

“…Several earlier works have considered the influence of photonic nanostructures on the FRET process; some conclude that the FRET rate depends linearly on the donor emission rate and the LDOS,23–27 whereas some others report a FRET rate independent of the LDOS 28–31. Earlier experiments on aluminum C‐shaped nanoapertures did not reveal noticeable changes in the FRET efficiency 32.…”

Nanofiber-mediated chiral radiative coupling between two atoms

“…The range and strength of the coupling can be enhanced by means of "dressing" the environment. A typical nonradiative Förster energy transfer range of ≤ 10 nm was surpassed by use of localized plasmons, whispering gallery modes, or microcavities [1][2][3][4][5][6][7][8][9][10][11][12]. Very fast (on the picosecond time scale) energy transfer was recorded in systems with quantum dots [13] and strongly bound excitons [14].…”