Förster resonance energy transfer

Förster resonance energy transfer (FRET), fluorescence resonance energy transfer, resonance energy transfer (RET) or electronic energy transfer (EET) is a mechanism describing energy transfer between two light-sensitive molecules (<a href="/facts/Chromophore/9RykVkek">chromophores</a>). A donor chromophore, initially in its electronic excited state, may transfer energy to an acceptor chromophore through nonradiative <a href="/facts/Dipole%25E2%2580%2593dipole_coupling/xIcFMvL7">dipole–dipole coupling</a>. The efficiency of this energy transfer is inversely proportional to the sixth power of the distance between donor and acceptor, making FRET extremely sensitive to small changes in distance.
Measurements of FRET efficiency can be used to determine if two <a href="/facts/Fluorophore/wDWBmYhn">fluorophores</a> are within a certain distance of each other. Such measurements are used as a research tool in fields including biology and chemistry.
FRET is analogous to <a href="/facts/Near_and_far_field/wS2Dp5lv">near-field</a> communication, in that the radius of interaction is much smaller than the <a href="/facts/Light/jeofpMn4">wavelength</a> of light emitted. In the near-field region, the excited chromophore emits a <a href="/facts/Virtual_photon/CfHFkVL3">virtual photon</a> that is instantly absorbed by a receiving chromophore. These virtual photons are undetectable, since their existence violates the conservation of energy and momentum, and hence FRET is known as a radiationless mechanism. <a href="/facts/Quantum_electrodynamics/zPteAr6G">Quantum electrodynamical</a> calculations have been used to determine that radiationless FRET and <a href="/facts/Radiative_transfer/nYE4KojG">radiative energy transfer</a> are the short- and long-range <a href="/facts/Asymptote/nvLPuxKa">asymptotes</a> of a single unified mechanism.

Förster resonance energy transfer open-in-new

Förster resonance energy transfer