title: Flat lens criterion by small-angle phase.
abstract: We show that a classical imaging criterion based on angular dependence of small-angle phase can be applied to any system composed of planar, uniform media to determine if it is a flat lens capable of forming a real paraxial image and to estimate the image location. The real paraxial image location obtained by this method shows agreement with past demonstrations of far-field flat-lens imaging and can even predict the location of super-resolved images in the near-field. The generality of this criterion leads to several new predictions: flat lenses for transverse-electric polarization using dielectric layers, a broadband flat lens working across the ultraviolet-visible spectrum, and a flat lens configuration with an image plane located up to several wavelengths from the exit surface. These predictions are supported by full-wave simulations. Our work shows that small-angle phase can be used as a generic metric to categorize and design flat lenses.
authors.forename: Peter
authors.initials: P
authors.lastname: Ott
authors.forename: Mohammed H
authors.initials: MH
authors.lastname: Al Shakhs
authors.forename: Henri J
authors.initials: HJ
authors.lastname: Lezec
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Chau
mesh_terms: D016880:Anisotropy; D003198:Computer Simulation; D021621:Imaging, Three-Dimensional; D007909:Lenses; D055620:Optical Phenomena; D012834:Silver
chemical_list: D012834:Silver