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Path: utzoo!watmath!watnot!watcgl!onfcanim!dave
From: dave@onfcanim.UUCP (Dave Martindale)
Newsgroups: net.audio,net.video
Subject: Re: CD Laser Frequency
Message-ID: <14914@onfcanim.UUCP>
Date: Tue, 2-Sep-86 08:54:17 EDT
Article-I.D.: onfcanim.14914
Posted: Tue Sep  2 08:54:17 1986
Date-Received: Wed, 3-Sep-86 04:24:51 EDT
References: <115@mruxc.UUCP> <1570@vax135.UUCP>
Reply-To: dave@onfcanim.UUCP (Dave Martindale)
Organization: National Film Board / Office national du film, Montreal
Lines: 19
Xref: watmath net.audio:9431 net.video:3173
Summary: 

In article <1570@vax135.UUCP> dh@vax135.UUCP (David N. Horn) writes:
>Sharp sells a laser diode for compact disc players. It puts out 5mw of optical
>power at 780 nm - just visible red.

700 nm is the generally-recognized end of the visible spectrum - 780 nm
is near-infrared.

For comparison, a He-Ne laser's light is 633 nm, red LED's are about 655,
and a ruby laser produces light of 694 nm.

So, if you're playing with laser diodes, be careful - you won't be able
to see the beam, but it can cause eye damage.

1mw is considered a "safe" level for visible lasers, since even if you
accidentally get the full beam in the eye you will blink fast enough to
prevent damage.  Eye damage will occur only if you avoid blinking.

With an infrared laser, you won't blink, and even a laser with much
less than 1mw output could burn your retina if you look at it long enough.