Here's a decent open-access review: https://doi.org/10.3390/sym16101377 https://doi.org/10.3390/sym16101377 The key point is that the sub-wavelength nature all

Here's a decent open-access review: https://doi.org/10.3390/sym16101377 https://doi.org/10.3390/sym16101377 The key point is that the sub-wavelength nature allows broader wavelength behavior and is distinct from conventional fresnel lenses. I suspect these plastic lenses will never be as sharp as a conventional lens, but presumably loads better than fresnel lenses and presumably worth it for weight-/size-restricted applications.