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From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.graphics
Subject: Re: Color desktop scanners (a technical
Message-ID: <46900035@uxe.cso.uiuc.edu>
Date: 10 Aug 89 20:09:00 GMT
References: <1869@ucsd.EDU>
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Nf-ID: #R:ucsd.EDU:1869:uxe.cso.uiuc.edu:46900035:000:879
Nf-From: uxe.cso.uiuc.edu!mcdonald    Aug 10 15:09:00 1989


>>There is no such thing as a white laser.  Lasers produce monochromatic light.
>WRONG!!  White light lasers DO exists.  I've used many in my time.
>Unfortunately, most white light lasers are krypton-ion and are about a
>meter in length, are water cooled, and consume LOTS of power (~60 amps).

>The white light is indeed a mixture of all colors of the spectrum and can
>be broken apart with the use of a prism.

"White" krypton lasers are not really white. They contain several
lines that add together to appear whice to the eye. They do 
make good color scanner sources, as the lines are in nice places.

The only really white lasers are the very, very shortest pulsed
femtosecond ones, or the continuum generated by focusing short
pulses into water.

This is not really a comp.graphics topic, but it is interesting
to people intereted in things like scanners.

Doug McDonald