this material is key

A group of researchers is working on “infrared nonlinear upconversion technology.”

The night vision devices we see today are large, heavy, and usually expensive. These reasons were enough to limit access to this technology select user group, like the military. Of course, not everyone is willing to spend hundreds of euros to see in the dark with a device weighing almost a kilogram mounted on their head. What if regular glasses could provide night vision? A group of scientists from Australia believes this is possible.

Members of the Transformation Meta-Optical Systems (TMOS) Center of Excellence have published a study in the journal Advanced Materials that addresses this problem using what they call “infrared nonlinear upconversion technology.” In other words, they are developing a night vision solution that is designed to work with thin sheet or very narrow lens widths. As experts note, miniaturization of system components can contribute to the widespread adoption of these solutions.

Night vision with traditional glasses

To better understand what TMOS offers us, it is necessary to know how analogue night vision works. Here we see a complex system in which a lens collects photons from the environment and directs them through a tube. electronic amplifier. Photons pass through a photocathode, which turns them into electrons. These electrons pass through the phosphor plate, become photons again, and recreate the scene in green and black.

If we stop for a moment and think about the fact that the system mentioned above has at least two types of lenses: photocathode, photomultiplier and electronic systems, then it may be difficult to imagine such a simple alternative as a sheet. Scientists have something simpler in mind. Instead of using so many elements, they propose a metasurface that increases the energy of photons and attracts them to the visible light spectrum without the need for electronic conversion.

As we say, there is key material in this alternative. Previously, we worked with gallium arsenide surfaces, but now we are focusing on lithium niobate. We are talking about a crystal that has been used for decades in optics and photonics, e.g. optical modulators for telecommunication networks. It is characterized by complete transparency in the visible range and allows the photon beam to spread widely across its surface.

The study’s lead author, Laura Valencia Molina, notes that many people believed that highly efficient infrared-to-visible conversion was impossible due to information loss. However, the team’s latest results show that these limitations have been overcome. Over time, we will know whether this technology can change the way night vision scopes are manufactured.

Images | TMOS | R.Louis Mack Photo | Laude Lagrange

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