Researchers at the University ETH Zurich have developed an ultra-thin lens that has the ability to convert infrared light into visible light. Lenses are essential optical devices used in cameras to produce clear images by directing light to a focal point.

The field of optics has seen significant advancements in recent years, with bulky cameras being transformed into compact smartphone cameras. Even high-performance smartphone cameras require multiple lenses, which are typically the thickest part of the device. This size limitation is due to the need for thick lenses to bend light effectively for capturing sharp images.

Over the past decade, metalenses have emerged as a solution to this issue. These flat lenses, which are 40 times thinner than a human hair, can modify the direction of light using nanostructures that are just a hundred nanometers in width and height.

By combining these nanostructures with special materials, researchers can explore unique properties of light, such as nonlinear optics, where light can be converted from one color to another. Lithium niobate is a material commonly used in this process, and researchers at ETH Zurich have developed a new method to create metalenses using this material.

The process involves a combination of chemical synthesis and precision nanoengineering, allowing for the creation of metalenses with precisely engineered nanostructures. These metalenses can focus light while simultaneously changing the wavelength of laser light, enabling the conversion of infrared light into visible light.

This breakthrough has various applications, including security features for banknotes, authentication of artworks, and making infrared light visible in sensors. The field of metasurfaces, which includes metalenses, holds great promise for future technological advancements.

Professor Rachel Grange, who led the research, highlights the potential impact of this cost-effective technology in the future and looks forward to further exploring its applications.