Infrared flash?

Riad S. Wahby rsw at jfet.org
Tue Apr 27 14:54:04 PDT 2004


Thomas Shaddack <shaddack at ns.arachne.cz> wrote:
> What would be the best approach? The energies here are more in the range
> of rotation/vibration changes than electrons jumping up and down between
> the energy states. How to convert a blast of electrical energy into a
> shower of near-IR photons?

If all you're trying to do is screw with surveillance cameras, a Xenon
tube is crushing a fly with a crane.

You can probably get away with an IR laser and a diffuser or something
to that effect.  It would be cheap (diode laser) and easy to build
(for a strobe-like effect it would take, what? a 555, a couple
resistors, a cap, and the diode).

If you want, you can probably extend this idea to much more IR output
just by adding more diodes and more juice.  I don't remember the
numbers off the top of my head, but IIRC the efficiency of a diode is
substantially greater than the efficiency of a Xenon tube.

Just took a quick look around, and it seems like a Xenon would still
work at 900nm:
        http://msp.rmit.edu.au/Article_03/02a.html
Apparently, Xenon tubes put out lots of crap around 900nm.  In fact,
it's somewhat more than they do in the visible spectrum.  If you get
yourself a good enough filter, you might be able to pull off a
mega-photon-dump setup.

-- 
Riad Wahby
rsw at jfet.org
MIT VI-2 M.Eng





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