Originally Posted by swarfmaker

Yes, it is a lot of Watts, most of which is not useful for this purpose. It reminds me of that old Star Trek episode where these light sensitive parasitic creatures (which reminded me of flying fried eggs!) make people go crazy. One gets Spock in the back and to cure him, they expose him to the full spectrum and intensity of the sun at a close distance. Then, Dr. McCoy figures out that only one wavelength is needed.

I have not been able to confirm that water is transparent to IR light at 1072nm. All I've been able to find is the following from

"Looking at the graph we can see how water transmits virtually all of the light within the ultraviolet and visual spectrum wavelengths. Within most of the infrared wavelengths water acts as a barrier to light apart from a peak transparency at 1072nm and a smaller optical window at 1280nm. If we compare this transmission spectrum with the known and recognised wavelengths at which photobiological reactions occur we can see quite clearly that living cells have adapted by evolution to light transmitted by water."

So, according to Restorelite, water is opaque to most of the IR spectrum, and transparent at 1072nm.

My thoughts were that if water is transparent at 1072nm, then a layer of water would act as a filter. Only 1072nm (and 1280nm) should pass through, all other IR light should be blocked. No fine tuning would be necessary. An incandescent heat lamp will produce a wide spectrum of light, from visible to far infrared (heating). Somewhere in there should be 1072. A layer of water in a plastic bag would then filter out the heating IR. Of course, a timer like is commonly found connected to those heat lamps they have in showers and bathrooms would be crucial in order to limit the time that the light was on.

But, I don't know how to test this. If water IS transparent to 1072nm, then this method should work. I also don't know what the IR transmission spectrum of ziplock plastic bags is either. I would also prefer to use LEDs, but until I can obtain some, this is the best I can come up with.

I was also wondering if there is a ionized gas light source, like neon lights, that instead of emitting visible light, would emit NIR light.

Here is a link to a German company that makes an industrial heating lamp that targets the NIR spectrum.