Dept. Elect. Eng. Technion – Israel Institute of Technology Rotating Beams Yoav Y. Schechner 1 Joint studies with J. Shamir, R. Piestun, A. Greengard

Yoav Schechner Waves having a Phase Dislocation propagation direction a helical wavefront

Yoav Schechner propagation direction helical wavefront surface local k -vectors (normals to the wavefront surface) have azimuthal component local k -vectors orbital angular momentum in the wave k vector : momentum Waves having a Phase Dislocation

Schechner & Shamir propagation direction Isotropic dislocation: helical wavefront propagation direction Anisotropic dislocation Parameterizations Morphological: Stretch angle Eccentricity Dark fringe: a limit of eccentricity Physical: Superposition of isotropic waves Dark fringe: annihilation of isotropic dislocations Angular momentum Anisotropic Dislocations

Rotating PSF Schechner

Schechner et. al, Physical Review E 1996 Computer-Generated Hologram (Diffractive Optical Element)

Utopian Geometric PSF Width changes linearly with z z Yoav Schechner

Standard PSF Width changes with z …by just a 2 nd order z

Rotating PSF Standard PSF Greengard, Schechner, Piestun

Greengard, Schechner, Piestun: Depth from diffracted rotation