Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!epicb!david
From: david@epicb.UUCP (David Cook)
Newsgroups: comp.graphics
Subject: Re: Lasers for RGB scanning
Message-ID: <646@epicb.UUCP>
Date: 16 Aug 89 13:23:54 GMT
References: <forgot>
Reply-To: david@epicb.UUCP (David Cook)
Organization: Truevision Inc., Indianapolis, IN
Lines: 38

In article <46900035@uxe.cso.uiuc.edu> mcdonald@uxe.cso.uiuc.edu writes:
>
>"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.
>

> I am not an expert on lasers, but I came across some info that might be of
> interest. On the Discovery Channel there was a piece on medical lasers.

> Some surgeons needed different frequencies of lasers for different tasks, so
> they were using a Dye laser. From what I could gather, a primary laser excited
> a dye which emmitted a secondary laser which could be tuned to almost any
> frequency.

> Using such a laser maybe you could tune it to Red, Green, or Blue for color
> scanning.

I'm not an expert on lasers either... but I believe that dye lasers would
not be a good choice for scanning... [1], they requre refreshing (ie.. the
dye elements require refreshing (pumping) and [2], they tend to be too
high of a power (read DANGEROUS) for most scanning applications.

In general, you want LOW POWER lasers for most scanning applications.
Helium-Neon produces light at 6328 anstroms (orangish-red) and can be
used for the red component... several companies, as of 1985, have anounced
helium-neon lasers tuned to operate in the blue-green area also.  Therefore,
it is possible to use several helium-neon lasers to get Red, Green and Blue.
(By the way, Dye lasers are very expensive and he-ne lasers are very cheap).
Besides he-ne... argon can also be used for the blue-green component, and
current argon technology requires no pumping and are fairly inexpensive
(as compared to other laser technology).  Some recent advancements, however
should be also considered... solid-state laser diodes which produce visible
(red) light, could also be used as the Red component.  I am not aware of
any blue or green laser diodes.

 -- David Cook
    uunet!epicb!david