We explore the propagation and diffraction of optical vortices (Laguerre-Gaussian beams) of varying azimuthal index past a circular obstacle and Young's double slits. When the beam and obstacle centers are aligned the famous spot of Arago, which arises for zero azimuthal index, is replaced for non-zero azimuthal indices by a dark spot of Arago, a simple consequence of the conserved phase singularity at the beam center. We explore how for larger azimuthal indices, as the beam and obstacle centers are progressively misaligned, the central dark spot breaks up into several dark spots of Arago. Using Young's double slits we can easily measure the azimuthal index of the vortex beam, even for polychromatic vortices generated by broadband supercontinuum radiation. (c) 2008 Elsevier B.V. All rights reserved.
|Number of pages||4|
|Journal||Physica C: Superconductivity and its Applications|
|Publication status||Published - 1 Apr 2008|
|Event||Vortex V Conference on Nanoscience and Engineering in Superconductivity - Rhodes, Greece|
Duration: 8 Sep 2007 → 14 Sep 2007
- white light optical vortices