From: "JACK L. URETSKY (C)1998; HEP DIVISION, ARGONNE NATIONAL LAB ARGONNE, IL 60439" <JLU@HEP.ANL.GOV>
Date: Thu, 8 Jul 1999 13:41:18 -0500
Hi Ludwik-
We don't have to work at the atomic level, to exhibit
the principle of non-linear response functions for intense radiation.
Just realize that at high intensities the transmitted (and, hence,
reflected) waves in a medium are proportional not just to E, the
electric intensity, but also to E^2, etc. But if E carries a single
frequency, then E^2 carries the doubled frequency, etc.
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But what do we mean by the "nonlinearity" when we refer to
atoms doubling a laser frequency ? What versus what is nonlinear?
Is the term nonlinearity appropriate in this case?
Ludwik Kowalski
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Regards,
Jack
"I scored the next great triumph for science myself,
to wit, how the milk gets into the cow. Both of us
had marveled over that mystery a long time. We had
followed the cows around for years - that is, in the
daytime - but had never caught them drinking fluid of
that color."
Mark Twain, Extract from Eve's
Autobiography