This has only ever been achieved in conventional lenses by stacking multiple lenses.
* Metalenses are thin, easy to fabricate and cost-effective. This breakthrough extends those advantages across the whole visible range of light. This is the next big step.
Metalenses — flat surfaces that use nanostructures to focus light — promise to revolutionize optics by replacing the bulky, curved lenses currently used in optical devices with a simple, flat surface. But, these metalenses have remained limited in the spectrum of light they can focus well.
Focusing the entire visible spectrum and white light – combination of all the colors of the spectrum — is so challenging because each wavelength moves through materials at different speeds. Red wavelengths, for example, will move through glass faster than the blue, so the two colors will reach the same location at different times resulting in different foci. This creates image distortions known as chromatic aberrations.