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Q & A: One photon at a time

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Most recent answer: 03/17/2009
Q:
why in photoelectric effect an electron absorbs only one photon.
- sachin (age 16)
lko,india
A:
In principle you can have absorption of multiple photons in the photoelectric effect.  In practice the probability is very very small under ordinary circumstances.  If you had a strong enough laser beam you could probably observe the effect.

LeeH

Multiple (two) photon absorption to drive fluorescence is now used in some special microscopes. It does require well-focused lasers, as well as molecules which are good at absorbing those two photons. Mike W.

(published on 03/17/2009)

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