Fisheye lenses make for some cool photos, but their most distinctive feature is that the glass is curved. The need for multiple bits of curved glass makes fisheye lenses both bulky and expensive. However, engineers at MIT and the University of Massachusetts at Lowell have figured out a way to make a fisheye lens that’s completely flat and could be applied in consumer devices, medical applications, and more.
The method of flattening something that is known for being bubble-like is pretty clever. To do it, the engineers used something called a “metalens,” or a flat piece of glass measuring just a millimetre thick. On the back of the metalens, they then carved teeny structures to scatter incoming light in a way that produces the same type of ultrawide, panoramic images a fisheye lens would. More specifically, the metalens is made from a transparent piece of calcium fluoride, with one side coated in a thin film of lead telluride. The teeny structural patterns were then carved using lithographic techniques.
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Metalenses are still rather experimental, and up until now researchers have been able to create high-resolution images for a field of view up to 60 degrees. To expand that further, you’d need to add additional materials to compensate for the resulting blurriness. But for this particular prototype, the engineers were able to increase the field of view to 180 degrees without adding any extra components. This particular prototype was made for infrared light, but the engineers say that their design can also be adapted to other wavelengths, including visible light.
This is legitimately neat and all, but what about actual, real-life applications besides, say, a more compact fisheye camera? According to the engineers, there’s actually a lot that a flat ultra wide lens could be used for. For starters, they could be used as depth sensors in smartphones, laptops, and wearables. So instead of needing a bulky camera bump if you want a wide-angle lens on your smartphone, you could have a super-thin lens instead.
“Currently, all 3D sensors have a limited field of view, which is why when you put your face away from your smartphone, it won’t recognise you,” Tian Gu, one of the MIT engineers who coauthored the study published in Nano Letters, said in a statement. “What we have here is a new 3D sensor that enables panoramic depth profiling, which could be useful for consumer electronic devices.”
They’re also considering using the new lens as a type of panoramic projector. The team also believes there could be medical applications — think imaging devices like endoscopes. (Imagine your doctors seeing a panoramic view of your insides in high resolution.) Similarly, low-profile wide angle lenses could also potentially be used to make less bulky VR headsets.
Compared to some more experimental discoveries, there are actually a decent number of practical applications for a flat wide-angle lens. But just because these engineers have figured it out doesn’t necessarily mean that next year’s smartphones will all be sporting the design. These sorts of things usually take a while to trickle down to consumers. That said, colour me intrigued by the sorts of features a things a flat wide-angle lens could enable.