Darmstadt 2008 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 23: Photonik II
Q 23.4: Talk
Tuesday, March 11, 2008, 17:15–17:30, 2B/C
3D analysis of polarization singularities in Laser speckle — •Florian Flossmann1, Kevin OHolleran1, Miles J. Padgett1, and Mark R. Dennis2 — 1University of Glasgow, United Kingdom, Department of Physics and Astronomy — 2University of Bristol, United Kingdom, H.H. Wills Physics Laboratory
Singularities of the polarization of light are the vectorial analogies to optical vortices (phase singularities) in scalar optics. Two types are known: L lines of linear polarization and C points of circular polarization, the latter can be further devided into lemon, star and monstar type C points. In 3D, they occur as L surfaces and C lines. Laser speckle fields, as a random superposition of coherent plane waves, form the most natural interference pattern and are therefore an obvious place to look for generic optical singularities "in the wild". Following our earlier work on the 3D topology of phase singularity lines in laser speckle (O`Holleran, submitted PRL) and on the natural unfolding of optical vortices into generic polarization singularities (Flossmann,PRL 2005), we investigate both experimentally and numerically the singularities of polarization (C lines and L surfaces) in a random vector field as found in polarized laser speckle. With that we present the (to our knowledge) very first truely 3 dimensional visualization of polarization singularities in optics from experimentally obtained data. We show for example, how C loops always consist of lemon, star and monstar type C points and perform a statistical analysis of the ratios of those types per line length.