title: Demonstration of focus-tunable diffractive Moiré-lenses.
abstract: In an earlier publication [Appl. Opt. 47, 3722 (2008)] we suggested an adaptive optical lens, which consists of two cascaded diffractive optical elements (DOEs). Due to the Moiré-effect the combined optical element acts as a Fresnel zone lens with a refractive power that can be continuously adjusted by a mutual rotation of the two stacked DOEs. Here we present an experimental realization of this concept. Four designs of these Moiré-DOEs (MDOEs) were fabricated in thin (0.7 mm) glass slides by lithography and subsequent etching. Each element was realized as a 16 phase level DOE designed for 633 nm illumination. Our experimental investigation shows that the Moiré-lenses have a broad adjustable refractive power range with a high efficiency, which allows one to use them for flexible beam steering and for imaging applications.
authors.affiliation: Division for Biomedical Physics, Innsbruck Medical University, A-6020 Innsbruck, Austria. stefan.bernet@i-med.ac.at
authors.forename: Stefan
authors.initials: S
authors.lastname: Bernet
authors.forename: Walter
authors.initials: W
authors.lastname: Harm
authors.forename: Monika
authors.initials: M
authors.lastname: Ritsch-Marte
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D012031:Refractometry / Q000295:instrumentation*