MIT Creates Zoomable Lens Without Any Moving Parts
The science of optics has revealed the scale and detail of the universe for centuries. With the right piece of glass, you can look at a distant galaxy or the wiggling flagella on a single bacteria. But lenses need to focus — they need to move. Engineers at MIT have developed a new type of “metalens” that can shift focus without any moving parts. This could change the way we build devices such as cameras and telescopes.
Currently, focusing a lens on objects requires the glass to move in some capacity, and that adds complication and bulk. That’s why, for example, high-zoom camera lenses have been so slow to come to smartphones — there’s just no room to add movable lens elements. It’s also why smartphones that do have optical zoom use multiple fixed lenses. For example, the new Samsung Galaxy S21 Ultra has 13, 26, 70, and 240mm lens equivalents in its giant camera array.
The metalens developed at MIT can focus on objects at multiple distances thanks to its tunable “phase-changing” material. When heated, the atomic structure of the material rearranges, allowing the lens to change the way in which it interacts with light. The design currently operates in infrared, but this is just a first step.
Readers of a certain age might have interacted with a similar phase-changing material on rewritable CDs and DVDs. This technology, now all but extinct, relies on a material called GST that contains germanium, antimony, and tellurium. When heated with laser pulses, GST can switch between transparent and opaque, allowing optical drives to write and delete data.
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