Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!mailrus!cornell!uw-beaver!ubc-cs!eric!joplin!dleblanc
From: dleblanc@joplin.mpr.ca (David LeBlanc)
Newsgroups: sci.electronics
Subject: Re: Looking for cheap visible red laser diodes
Keywords: laser diode red
Message-ID: <1975@eric.mpr.ca>
Date: 20 Dec 89 17:45:27 GMT
References: <2290@sactoh0.UUCP> <1237@mit-amt.MEDIA.MIT.EDU>
Sender: news@eric.mpr.ca
Reply-To: dleblanc@joplin.UUCP (David LeBlanc)
Organization: Microtel Pacific Research Ltd., Burnaby, B.C., Canada
Lines: 27

>mahaun@sactoh0.UUCP (Mark A. Haun) writes:
>> Does anybody know of a source for visible red laser diodes?
>
In article <1237@mit-amt.MEDIA.MIT.EDU> adam@mit-amt.MEDIA.MIT.EDU 
(Adam Glass) replies:
>A local surplus store is selling them for $19 each. They have laser diodes
>from 7 to 25 watts. Since I know almost nothing about lasers, let me quote
>them:
>  "These Gallium-Arsenide injection diodes emit coherent infra-red
>   radiation. The diode is built in a hetero-junction structure,
>   consisting of 3 distinct layers: N-type, P-type gallium asenide [sic]
>   and P-type gallium aluminum arsenide. Specs: 7 to 25 watts, lfm 40A,
>   Lth 1A, typical peak forward coltage @ Lfm 8 volts, @ 50 ma 1.2 volts."
>
No flames intended, but 7 to 25 watts sounds a little high (like a few
orders of magnitude) for a laser diode.  The laser diodes used in
telecommunications launch (best case) somewhere around 0 dBm (1 mW) into
a single mode fiber.  My guess is that the spec sheet was wrong and they
meant milliwatts (eg. 7 to 25 mW).  Note that 7 to 25 Watts is not "low
power" when you consider that the energy is coherent and concentrated in
a narrow beam.

Please tell me if I'm out in left field on this - I could think of a lot
of really neat uses for a device like this.

Dave LeBlanc
dleblanc@joplin.mpr.ca