Versatile Diffractive Flat Optics

Abstract

Recently, we have shown that allowing the phase in the image plane of a flat lens to be a free parameter enables imaging properties of unprecedented versatility in flat, multilevel diffractive lenses through careful design of different diffractive surfaces. The properties we have shown in such flat lenses include super-achromaticity, extreme depth-of-focus and high numerical aperture. These flat lenses can be easily fabricated using one-step grayscale lithography.