Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!ucbvax!hplabs!hpl-opus!hpspdra!jeff
From: jeff@hpspdra.HP.COM (Jeff Gibson)
Newsgroups: comp.graphics
Subject: Re: Re: Lasers for RGB scanning
Message-ID: <12400002@hpspdra.HP.COM>
Date: 17 Aug 89 23:21:26 GMT
References: <646@epicb.UUCP>
Organization: HP Stanford Park - Palo Alto, CA
Lines: 26

Hmmmmmmmm, lasers.

I just left a laser manufacturer where I worked on a "White Light"
product.  These systems are typically used in the Light Show industry
for medium power applications such as auditorium and planetarium shows.
There are low-powered versions (air-cooled, milliwatt power levels)
which are also sold into this market, although they are a very small
percentage of the marketplace.

White light lasers are an attractive alternative for laser scanning if
beam quality is not a big issue, ie; small spot sizes are not necessary.
White lights run multimode which means that the various colors will have
different beam diameters and Transverse Modes.  

Multiple laser systems as described ( A red Hene, a green Hene) are a
way around the beam problem, but after all the lasers are added together
the total cost may exceed that of a single white-light.  I also believe
that for a "balanced" RGB setup, or one which has somewhat equal power
levels of red, green, and blue, one still needs to utilize a Hene for
the Red and a air-cooled Argon for the green and the blue.  Red HeNe's
range from .5 to 20 mw, whereas green HeNe's have yet to exceed 1 mw in
production quantities.  And blue HeNe's simply do not exist.

For more information on RGB scanners, look up the laser entertainment
folk who build them and sell them as stand-alone products, both as
single white-light systems, or as multiple laser systems.