Talk:Photodarkening

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I stop to write the article because I cannot give the definition:

Is photodarkening just fuzzy name of class of phenomena,

or it can be interpreted also as a physical quantity?

In the last case, we need formal definition, relations with other physical quantities and way(s) of measurement. It seems photodarkening should have dimension of frequency.

For example, absorption increases as ~A=A_0 (1+D t)~,

where ~A_0~ is background absorption,

~t~ is time and

~D~ is photodarkening, specific material parameter, which depends on intensity and frequency and of irradiating light.

Then, we could expect, the transmission coefficient of a sample of length ~L~ of a photodarkening medium should behave as ~K=\exp(A_0 L~ (1+D t))~.

I do not place the definition above to the article, because I cannot find a source with such a definition. Even worse; I am not sure if it is correct definition. The only I am sure, the correct definition must have similar structure.

However, I am not satisfied with the description by the original papers, and much less with the definition by [[http://www.rp-photonics.com/photodarkening.html Encyclopedia of Laser Physics and Technology]]. Can anybody define the term? The colelagues say, write and read: "photodarkening", "photodarkening".. Well, what is photodarkening? dima 08:33, 13 April 2007 (UTC)