Thanks to a new technology developed by Tel Aviv University, it is now possible to image gases and substances such as hydrogen, carbon, and sodium, each of which has a unique color in the infrared spectrum, as well as biological compounds that are found in nature but are ‘invisible’ to the naked eye or ordinary cameras. The technology allows cameras to recognize colors that the human eye and even ordinary cameras cannot perceive.
As noted by scientists, the technology has groundbreaking applications in various fields from computer gaming and photography and the disciplines of security, medicine, and astronomy.
Dr. Michael Mrejen of TAU’s Department of Physics of Condensed Material said, “The human eye picks up photons at wavelengths between 400 nanometers and 700 nanometers—between the wavelengths of blue and red. But that’s only a tiny part of the electromagnetic spectrum, including radio waves, microwaves, X-rays, and more. Below 400 nanometers, there is ultraviolet or UV radiation, and above 700 nanometers, there is infrared radiation, which itself is divided into near-, mid- and far-infrared.”
“In each of these parts of the electromagnetic spectrum, there is a great deal of information on materials encoded as ‘colors’ that has until now been hidden from view.”
Scientists explain, “colors in these parts of the spectrum are of great importance since many materials have a unique signature expressed as a color, especially in the mid-infrared range. For example, cancer cells could be easily detected as they have a higher concentration of molecules of a certain type.”
Existing infrared detection technologies are costly and generally incapable of rendering those ‘colors.’ In medical imaging, experiments have been acted in which infrared images are converted into visible light to identify the molecules’ cancer cells. Until now, this conversion required advanced and costly cameras, which were not necessarily accessible for general use.
But in their study, TAU researchers were able to develop cheap and efficient technology that could mount on a standard camera and allows, for the first time, the conversion of photons of light from the entire mid-infrared region to the visible region, at frequencies that the human eye and the standard camera can pick up.
Prof. Haim Suchowski of TAU’s Department of Physics of Condensed Material said, “We humans can see between red and blue. If we could see in the infrared realm, we would see that hydrogen, carbon, and sodium have a unique color. So an environmental monitoring satellite could ‘see’ a pollutant being emitted from a plant, or a spy satellite would see where explosives or uranium are being hidden. Also, since every object emits heat in the infrared, all this information could be seen even at night.”
- Michael Mrejen et al., Multicolor Time‐Resolved Upconversion Imaging by Adiabatic Sum Frequency Conversion, Laser & Photonics Reviews (2020). DOI: 10.1002/lpor.202000040