RE: Shifting wavelengths

[ADavidhazy <ANDPPH@xxxxxxxxxxxxxxxxxx>]

> I have a question, mainly theorical. Is there any way to "shift" wavelength?

There are several way to do this. Image converter cameras for example place an
IR image on a photocathode and this then is reimaged by the electromagnetic
lens onto a fluorescent screen and there one sees a visible image ... typically
green.

Thermal cameras do something similar but use different technology. I guess you
could even say that IR capable video cameras do that.

However, there are other materials that exhibit the anti-Stokes effect and that
is that they "glow" in the visible region of the spectrum when hit with IR.
Some of these materials need to be preexposed to UV or blue radiation previous
to use. Some such materials are used to detect the presence or path of an IR
laser beam in a laser set-up. Edmund Scienctific I believe sold such material. 
I once installed this in a Polaroid pack back and tried to make IR photographs
onto non-IR senstive Polaroid film ... it worked but the results were not
really useful.                                          

Of course, wavelength shifting is more common going from short to long and the
materials that do this are called "fluorescent" ... the most common direction
is to go from UV into the visible.

Or so I think is the case ...

Andrew  o o  0 0 o . o  Davidhazy, Imaging and Photo Tech
         \/\/\/\/\/\/          http://www.rit.edu/~andpph
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