Berlin 2014 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 67: Photonics III
Q 67.3: Vortrag
Freitag, 21. März 2014, 17:00–17:15, UDL HS3038
Optical Vortex Generation from Molecular Chromophore Arrays — •Matt Coles1,2, Mathew Williams2, Kamel Saadi2, David Bradshaw2, and David Andrews2 — 1Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Deutschland — 2School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
Light endowed with orbital angular momentum, frequently termed optical vortex light, is commonly generated by passing a conventional beam through suitably constructed optical elements; for example, optical phase plates or bifurcated diffraction gratings. It emerges that the necessary phase structure for vortex propagation can be produced directly through the creation of twisted light from the vacuum. The mechanism is founded on optical emission from a family of chromophore nano-arrays that satisfy specific constraints, based on geometric and symmetry arguments. Each such array can support pairs of electronically delocalized excitons whose angular phase progression is responsible for the twisted wave-front of the emitted radiation. These pairs are equal in energy, however their decay leads to optical vortex light with opposing signs. The exciton symmetry dictates the maximum magnitude of the orbital angular momentum and an analysis reveals the conditions necessary to deliver optical vortices with arbitrary twist.