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From: nagle@well.sf.ca.us (John Nagle)
Newsgroups: sci.electronics
Subject: Re: Sources for high-brightness red LEDs
Message-ID: <22022@well.sf.ca.us>
Date: 7 Dec 90 19:18:18 GMT
References: <10926@rama.UUCP> <3340009@hpcvca.CV.HP.COM>
Lines: 13


     What's the output wavelength on these things, and how stable is it?
Is it narrow and stable enough that you can use an interference filter
to block other light sources at a detector?

     On interference filters: the passband changes with the off-axis
angle, according to the literature with one such filter.  Is the
relationship   w2 = w1 / (cos a)  where w1 is the on-axis wavelength,
a is the off-axis angle, and w2 is the off-axis pass wavelength?
That would require very careful alignment.  Or is it something less
severe, and if so, what's the mechanism?

					John Nagle