This flat metalens is the first single lens that can focus the entire visible spectrum of light -- including white light -- in the same spot and in high resolution. It uses arrays of titanium dioxide nanofins to equally focus wavelengths of light and eliminate chromatic aberration. Credit: Jared Sisler/Harvard SEAS<br>
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https://m.phys.org/news/2018-01-metalens-focuses-rainbow-possibilities-virtual.html
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https://m.phys.org/news/2018-01-metalens-focuses-rainbow-possibilities-virtual.html