On Wed, 02 Nov 2005 04:30:16 GMT, Cecil Moore wrote:

Owen Duffy wrote:
Has someone got a good definition of coherent.

From the IEEE Dictionary: "coherent (1)(fiber optics) Characterized by
a fixed phase relationship between points on an electromagnetic wave ...
(2)(laser maser) A light beam is said to be coherent when the electric
vector at any point in it is related to that at any other point by a
definite, continuous sinusoidal function."


Thanks Cecil and Roy... obviously my understanding (in-phase) was just
too narrow. I did find Roy's text more coherent!

Interesting to Google for the use of the term, and it appears to be
very loosely used... I guess to some extent because of its roots in
common language and the ordinary meaning of the word.

Owen
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