Laser-assisted resonance energy transfer

On input of a laser beam (of adequate intensity) the transfer rate of resonance energy transfer may be altered - this mechanism is known as laser-assisted resonance energy transfer.

Feynman diagram for laser assisted resonance energy transfer

Its Feynman diagram is shown on the left:

  • Region I (before interaction i) - the right and left molecules are excited (red) and unexcited (blue), respectively
  • Region II (between i and j) - a laser photon is absorbed by the right molecule and it moves into an intermediate state (green)
  • Region III (between j and k) - a photon is emitted by the right molecule and it moves into the unexcited state (blue)
  • Region IV (between k and l) - this photon is absorbed by the left molecule and it moves into an intermediate state (green)
  • Region V (after l) - a laser photon is stimulated from the left molecule and it moves into an excited state (red)

All-optical switching

All-optical switching is the ability of light to control light, circumventing the bottlenecks resulting from conversion of an optical signal into an electronic signal within applications such as routers.

As a result, all-optical switching has the capacity to greatly increase the speeds of telecommunication and computing systems. Our proposed all-optical switch is based on laser-assisted resonance energy transfer and is illustrated on the right.

Illustratation of an all-optical switch

In certain configurations RET is excluded, but may be reactivated on the input of the laser - i.e. the basis for an all-optical switch:

  • Left-hand side: the initially excited molecule (red dot) will not transfer energy to the unexcited molecule (green dot) below it.
  • Right-hand side: the presence of the laser beam (green arrow) activates the energy / photon transfer.
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