Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!sharkey!edsews!uunet!microsoft!w-colinp
From: w-colinp@microsoft.UUCP (Colin Plumb)
Newsgroups: sci.electronics
Subject: Re: Correct Terminology (was Re: Radar Detectors (Ka band) ...)
Message-ID: <732@microsoft.UUCP>
Date: 24 Feb 89 07:44:41 GMT
References: <603@icus.islp.ny.us> <7944@netnews.upenn.edu> <5632@homxc.ATT.COM> <55@enuxha.eas.asu.edu>
Reply-To: w-colinp@microsoft.uucp (Colin Plumb)
Organization: very little
Lines: 16

kluksdah@enuxha.eas.asu.edu (Norman C. Kluksdahl) wrote:
> Beware the trap of incorrect terminology!  There is a great difference
> between COHERENT light and COLLIMATED light.  A laser is pretty much
> coherent light in that the spectrum of output is nearly delta-function like.
> However, LED's are also nearly coherent in that their output is at nearly
> a single frequency, discounting some small amount of higher and lower energy
> photons arising from trap states within the energy gap and higher-energy
> radiative recombinations.

Funny, and I was always told that was monochromatic.  Coherent also implies
in-phase.  That's why you can do all the fun interference pattern things
with lasers.
-- 
	-Colin (uunet!microsoft!w-colinp)

"Don't listen to me.  I never do."