Enhancing Spontaneous emission in a vacuum standing wave

  • #1
Hi,

it is well known that spontaneous emission of an atom can be enhanced, if the atom sits at a node of the vacuum standing wave field in a cavity.

My question is, why is it the node? At a node of a standing wave, there is zero intensity, so there should be no interaction between the atom and the virtual photons there. Shouldn't it be the anti-node?

Regards
 

Answers and Replies

  • #2
Cthugha
Science Advisor
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Is that so? If you want to enhance spontaneous emission by means of the Purcell effect, you always try to place your emitter at the antinode of the cavity field. You try to place it at the node in order to inhibit spontaneous emission.

Do you have a reference for that claim? Maybe they do not discuss the Purcell effect, but some other effect?
 
  • #3
f95toli
Science Advisor
Gold Member
3,039
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What type of field? E or B?
You want to place your atom where the coupling (g) between the relevant field (which for an atom would usually be the B field) and the relevant transition is the strongest.

This is a good example of a situation which is easier to understand when dealing with qubits coupled to a transmission line resonator (lambda/2) since you can use normal circuit theory. If the qubit is capacitively coupled to the resonator you want to place it at either end where the voltage is maximum; if the coupling is inductive in the centre where the current has a max.
Note that the physics is absolutely identical to the situation where you have an atom in a 3D cavity.
 
  • #4
Hi,

maybe my professor did a mistake on his sheets... after paper research, I only found implications of the enhancement for the anti nodes. I thought it made no sense^^
 
  • #5
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