Van der Waals-Zeeman Colloquium
11 Dec. 2007, 16:00h
Ending the discussion on the the Purcell factor of spontaneous emission
Prof. Ad Lagendijk
Amolf and University of Amsterdam
In 1946 E.M. Purcell described in a pioneering paper an effect that is now know as "the "Purcell effect", denoting the ratio of the rate of spontanous emission in a cavity compared to the value in vacuum. Purcell also quantified this effect with a factor (now known as the "Purcell factor".) At present, the Purcell factor is very broadly-used as the guiding principle for designing and characterizing optimal optical (nano-)cavities (Google hits on "Purcell effect" and "Purcell factor" are about 23500).
There always has been an ambiguity about the Purcell factor. This ambiguity can be found in the literature, but is more pronounced in scientific discussions and in scientific presentations.
We have found the exact solution and removed all ambiguities related to the Purcell factor. We have shown that the enhancement in cavities is given by a much simpler expression than before.