“Seeing" the Invisible :
I am a retired physicist who now spends most of my time pursuing my lifelong avocation of landscape photography. I capture primarily infrared (IR) images, both with film and digital cameras. The wavelengths of IR light used in photography are invisible to all land-based creatures except the pit viper.
Given my background as an experimental physicist, it is not surprising that I would be interested in IR photography. My fascination with ways of "seeing" the invisible dates back to an undergraduate lab in physical optics. The techniques of physical optics (using devices to produce visible evidence of invisible phenomena) were used extensively to obtain experimental proof of quantum mechanics in the early 20th century.
As a professional physicist, I have worked in elementary particle research and medical imaging. The two are related, as both use photographic and digital image capture to visualize that which cannot be seen optically (with the naked eye or a microscope).
In elementary particle research, tracks left by charged particles in cloud chambers and bubble chambers have been analyzed to make many fundamental discoveries. Photographs of tracks in cloud chambers led to the discovery of antimatter (the positron, discovered in 1932), the muon (a "heavy" electron, discovered in 1934) and the kaon (the first "strange" elementary particle, discovered in 1947).
Bubble chambers, particularly the Berkeley 72 inch hydrogen bubble chamber (I personally did research with this instrument), were responsible for the discovery of numerous short-lived particles--discovery that was important for the development of the quark hypothesis, and the "standard model" of fundamental particles and how they interact.
In a more familiar vein, medical imaging uses X-rays, ultrasound, CT scanning, MRI scanning, and PET scanning to visualize the interior of the human body that is, of course, otherwise invisible.
Now I make infrared photographs, once again to "see" the invisible.