Apochromatic telescopes (those bringing three wavelengths to a common focus) are of top-notch quality for astronomical observation.  So perhaps that speaks well for these flat lenses.  But more importantly, and omitted from the news release, is the point spread function, which is the image in the focal plane of a point object.   --  Gene From: Mike Speciner <ms@alum.mit.edu> To: math-fun <math-fun@mailman.xmission.com> Sent: Friday, February 20, 2015 2:24 PM Subject: Re: [math-fun] "Achromatic metasurface" breakthrough in lens technology? This prototype apparently only focuses three wavelengths, and presumably doesn't deal with all the rest. It seems unlikely to be able to capture a naturally illuminated scene, but perhaps a scene illuminated with narrow band red, green, and blue? The article did say that they think they can expand from three to many, and maybe that's good enough. On 20-Feb-15 16:45, Warren D Smith wrote:

This looks very interesting and potentially revolutionary. Think depends how expensive it is to manufacture these.

http://www.seas.harvard.edu/news/2015/02/perfect-colors-captured-with-one-ul...