title: Design of diffractive lenses that generate optical nulls without phase singularities.
abstract: We exploit a technique, based on nonlinear optimization, to design diffractive lenses that focus optical nulls without any phase singularities. To ensure ease of fabrication, these lenses are composed of concentric circular zones. Furthermore, we show that this technique is readily extended to multiple wavelengths and can be used to improve tolerance to fabrication errors.
authors.affiliation: Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. rmenon@mit.edu
authors.forename: Rajesh
authors.initials: R
authors.lastname: Menon
authors.forename: Paul
authors.initials: P
authors.lastname: Rogge
authors.forename: Hsin-Yu
authors.initials: HY
authors.lastname: Tsai