Kaya Special Optics, Inc. is introducing a newly developed product called the “Infrared See-Through Filter PF. PF is a special optical device that helps to visually penetrate an object’s surface in order to view whatever lies below. The manufacturers claim that the Infrared See-Through Filter PF can’t totally penetrate all surfaces but it can provide a high degree of “see-through”.
Here’s how it works…
All reflected light that we can see with the naked eye represents a fractional portion of the electromagnetic spectrum, which is infinite. We refer to this section as “visible light”. All around us, light is reflected which the human retina cannot detect, such as ultraviolet and infra-red radiation.
The visible part of the spectrum falls between the wavelengths of 430nm~690nm. (1nm=10-9m) Infrared rays have much larger wavelengths than this. We divide them into “Near Infrared Rays” (690nm-4,000nm) and “Extreme Infrared Rays” (over 4,000nm).
Unlike ultraviolet and visible rays, infrared rays tend to penetrate any medium rather easily because of their large wavelengths. This also means that infrared rays are not refracted much at all when passing from one medium to another. When we shine sunlight through a prism, it is refracted at an angle according to its wavelength. The blue end of the visible spectrum has the shortest wavelength, so is refracted the most. At the other end of the spectrum, beyond the red, visible light, infrared rays are barely refracted at all because of their long wavelength.
The KAYA PF exploits this characteristic of infrared light. It only lets through these long-wavelength rays, which have low refractive rays, and not all the ultraviolet and visible rays.