2021-02-25

MIT scientists have created a camera lens that can adjust the focus without moving parts

By yqqlm yqqlm

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On the contrary, this “ultra-thin tunable metalens” rearranges its atomic structure according to heat .

MIT scientists have created a camera lens that can adjust the focus without moving parts

This material is rewritable A new variation of germanium/antimony/tellurium materials used in CD and DVD. In these applications, laser heat is used to switch materials between transparent and opaque states. But the MIT team added selenium to it and found that when heat was added, its atomic structure “transformed from an amorphous, random atomic entanglement to a more ordered crystal structure”, changing its transparency without changing its transparency. Its refractive power.

The surface of the metalens is engraved with tiny, precise pattern structures, which can be designed to refract or reflect light in a certain way. When the material is heated, its optical properties change. In the configuration of the team’s prototype, it focuses infrared light on a near point at room temperature, and then moves its focus to a farther place as it heats up.

The team tested the metalens by placing the metalens on a stage and irradiating it with a laser beam tuned to the infrared band. The researchers placed two transparent resolution images at different distances in front of it and found that it can distinguish the sharp image of the closer image at room temperature, and after heating, even after removing the heat source, it can Identify the same sharp image of the farther picture.

MIT scientists have created a camera lens that can adjust the focus without moving parts(1)

“Our results show that we The ultra-thin tunable lens can achieve orthoscopic images of overlapping objects positioned at different depths without moving parts, which is comparable to traditional and bulky optical systems.” MIT Materials Research Experiment Said Gu Tian, ​​a research scientist in the laboratory.

The team believes that it can be manufactured with an integrated micro-heater, which can “heat the material quickly with short millisecond pulses” and precisely adjust the temperature so that it is in the middle of the range between the minimum and maximum focal lengths It achieves continuous focusing-although it is not clear how fast it can cool down and reset the focus to the minimum distance.

“Generally speaking, when one person manufactures an optical device, the post-processing of adjusting its characteristics is very challenging,” said team member Mikhail Shalaginov. “This is why having this platform is like the holy grail of optical engineers, allowing (metallic) to switch focus effectively on a large scale.”

MIT scientists have created a camera lens that can adjust the focus without moving parts(2)

The team said that this infrared prototype can be used in micro thermal sights, ultra-small thermal imaging cameras, and low-key night vision goggles. Play a role. According to the researchers, through further development, ultra-small zoom lenses for smartphones can be realized without moving parts, etc.

The paper about this research was published in the journal Nature Communications.