Wafer-thin fisheye lenses for smartphones

In tests, the lens produced 180-degree images that were crisp and clear

Spotted: Fisheye lenses are typically used to capture 180-degree, panoramic views in a single shot. This would be a very useful feature to have in a smartphone, except that fisheye lenses are made from multiple pieces of curved glass, which makes them bulky and costly to produce. Now, engineers at MIT have designed a fisheye lens that is wafer-thin and completely flat.

Fisheye lenses work by distorting incoming light via their shape. The new, thinner lenses achieve this using tiny structures that precisely scatter light in the same way as conventional, curved lenses. The lens is made from calcium fluoride, with a thin film of telluride deposited on one side. A pattern of optical structures is then carved into the film.

The team placed an opening on the front side to let in light. The light is dispersed onto the backside of the lens from different and continuous angles to give a panoramic view. The initial design only works in the infrared spectrum, but the researchers say it could be adapted to capture images in other wavelengths, including visible light.

In tests, the lens produced 180-degree images that were crisp and clear. Researcher Juejun Hu, associate professor in MIT’s Department of Materials Science, described the design as a surprise, saying, “some have thought it would be impossible to make a metalens with an ultra-wide-field view. The fact that this can actually realise fisheye images is completely outside expectation. This isn’t just light-bending — it’s mind-bending.”

The thin fisheye lens joins other recent innovations that combine thin films with electronics to deliver unique functions. Some developments in thin-film technology we have covered recently at Springwise include wearables made from bio-waste and peelable circuits.

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