Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a revolutionary lens. It’s flat instead of curved, and it focuses the entire visible spectrum and white light in a single point. So far, this was only possible by stacking multiple lenses. But with this new invention, it’s possible to do it with a single lens. This discovery is interesting for us because it could revolutionize photography. If the commercial development starts, metalenses could make the gear far less bulky in the future.
As Leah Burrows writes, focusing the entire visible spectrum along with white light is challenging. He explains that “each wavelength moves through materials at different speeds.” This is why cameras and other optical instruments use multiple curved lenses. They all have different thickness and use different materials, so the wavelengths meet at the same spot. However, the stacked lenses make the device bulkier.
Federico Capasso, the senior author of the research, points out that metalenses have advantages over traditional lenses. He says they are “thin, easy to fabricate and cost effective,” and adds that “this is the next big step.”
These metalenses use arrays of titanium dioxide nanofins. By optimizing the nanofins’ shape, width, distance, and height, metalenses focus wavelengths of light equally and eliminate chromatic aberrations.
Alexander Zhu, a co-author of the study, explains that metalenses enable “high quality, white light imaging.” He claims this brings the scientists closer to their goal of incorporating these lenses into cameras. If metalenses reach the commercial production, I imagine the camera lenses will be much smaller and lighter. Perhaps it could affect and improve the lenses in mobile phone cameras, too.
According to Harvard SEAS, the next step for the scientists is to scale up the lens, to about 1 cm in diameter. This will open new possibilities in the areas such as augmented and virtual reality.
[via Harvard SEAS; Image courtesy of Jared Sisler/Harvard SEAS]