Lighting the Way

Light is one of the primary things that allows humans to function effectively and efficiently. Indeed, without it, we are basically hopeless; however, a lot of it is...well, missing. Perhaps a better way of articulating it is by noting that a lot of light is invisible to us.

Light, or electromagnetic radiation, is actually a really wide spectrum, but only a small portion can be seen by humans. The region that we can see is called the visible spectrum because (duh) it is visible to us.

But there are a host of other regions.

All-in-all, the regions include radio wave, microwave, terahertz (or sub-millimeter) radiation, infrared, visible light, ultraviolet, X-rays, and gamma rays. In 1800, Sir Frederick William Herschel discovered infrared. Far infrared waves are thermal, meaning that we feel them in the form of heat, but can't see them.

Just like visible light, infrared rays can also be reflected, refracted, absorbed and transmitted.

Making the Invisible Visible

Credits: Dr. Nils Wilhelm Rosemann

Now, a team of scientists at Philipps-Universität Marburg in Germany, headed by Dr. Nils Wilhelm Rosemann, developed a substance that can transform infrared light into visible light. They designed a diamondoid-like structure of tin and sulfur and coated the scaffolding with organic ligands.

If you are wondering what this amorphous powder compound is called, it has the lovely designation [(RdelocSn)4S6](Rdeloc=4–(CH2=CH)–C6H4)...sounds rather pretty, no? It is non-volatile, air-stable, and thermally stable up to 300°C (572 °F).

For their work, the team fired an infrared laser at a thin film of the substance. The molecules of the substance then alter the wavelength of the light through a non-linear interaction process that produces light at wavelengths from the visible spectrum.

The scientists said that the emitted light has characteristics that are desirable for devices that require high spatial resolution, and it has other applications such as projection systems.

This discovery could also advance directed illumination technology (which is used in advanced weapon systems that use high energy lasers), as the materials used in the experiment are cheap, readily available, and easy to scale.

Dr. Rosemann's  findings are published in the journal Science.

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