Suche nach „[K.] [O'Holleran]“ hat 4 Publikationen gefunden

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen

Zeitschriftenartikel

K. O'Holleran, Florian Flossmann, M. Padgett, M. Dennis

Fractality of light's darkness

Physical Review Letters - moving physics forward, vol. 100, no. 053902

Abstract anzeigen

Natural light fields are threaded by lines of darkness. For monochromatic light, the phenomenon is familiar in laser speckle, i.e., the black points that appear in the scattered light. These black points are optical vortices that extend as lines throughout the volume of the field. We establish by numerical simulations, supported by experiments, that these vortex lines have the fractal properties of a Brownian random walk. Approximately 73% of the lines percolate through the optical beam, the remainder forming closed loops. Our statistical results are similar to those of vortices in random discrete lattice models of cosmic strings, implying that the statistics of singularities in random optical fields exhibit universal behavior.

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen

Zeitschriftenartikel

J. Götte, K. O'Holleran, D. Preece, Florian Flossmann, S. Franke-Arnold, S. Barnett, M. Padgett

Light beams with fractional orbital angular momentum and their vortexs tructure

Optics Express, vol. 16, no. 2, pp. 993-1006

DOI: 10.1364/OE.16.000993

Abstract anzeigen

Light emerging from a spiral phase plate with a non-integer phase step has a complicated vortex structure and is unstable on propagation. We generate light carrying fractional orbital angular momentum (OAM) not with a phase step but by a synthesis of Laguerre-Gaussian modes. By limiting the number of different Gouy phases in the superposition we produce a light beam which is well characterised in terms of its propagation. We believe that their structural stability makes these beams ideal for quantum information processes utilising fractional OAM states.

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen

Zeitschriftenartikel

Florian Flossmann, K. O'Holleran, M. Padgett, M. Dennis

Polarization Singularities in 2D and 3D Speckle Fields

Physical Review Letters - moving physics forward, vol. 100, no. 203902

Abstract anzeigen

The 3D structure of randomly polarized light fields is exemplified by its polarization singularities: lines along which the polarization is purely circular (C lines) and surfaces on which the polarization is linear (L surfaces). We visualize these polarization singularities experimentally in vector laser speckle fields, and in numerical simulations of random wave superpositions. Our results confirm previous analytical predictions [M. R. Dennis, Opt. Commun. 213, 201 (2002)] regarding the statistical distribution of types of C points and relate their 2D properties to their 3D structure.

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen

Zeitschriftenartikel

K. O'Holleran, Florian Flossmann, M. Dennis, M. Padgett

Methodology for imaging the 3D structure of singularities in scalar and vector optical fields

Journal of Optics, vol. 11, no. 0094020

DOI: 10.1088/1464-4258/11/9/094020