Anton Petrov:
https://www.youtube.com/watch?v=wQh9ezBdoPM
Also cross-posted from: https://programming.dev/post/31467824
A team of physicists at ETH Zurich has created a tiny metalens that can half the wavelength of incident light.
They have achieved this using a special metal-oxide lens material called lithium niobate and through nanoscale pattern, stamped into the material.
Such metalenses could be used as a security feature on banknotes or in the fabrication of ultra-thin elements for cameras.
It can only work up to a limiting frequency. It's probably in the visible spectrum or in near ultra-violet (that's how material go). But since it's a video, I won't go check it.