Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 15: Poster 1: Quanteninformation, Quanteneffekte, Laserentwicklung, Laseranwendungen, Ultrakurze Pulse, Photonik
Q 15.72: Poster
Montag, 14. März 2011, 16:30–19:30, P1
Optical vortex supercontinuum and topological charge transfer — •Peter Hansinger1,2, Alexander Dreischuh1,3, Georgi Maleshkov3, and Gerhard Georg Paulus1,2 — 1Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany — 2Helmholtz-Institut Jena, Helmholtzweg 4, 07743 Jena, Germany — 3Department of Quantum Electronics, Sofia University, 5 James Bourchier Blvd., Sofia-1164, Bulgaria
Optical vortices, also known as screw dislocations, are singular points within the phase of a light beam. The phase varies by a multiple of 2π over the angular coordinate φ, and is therefore undefined in the center and the intensity becomes zero at this point. Such donut beams have become useful e.g. in optical micromanipulation as so-called optical tweezers. Particularly interesting is the generation of optical vortices in broadband coherent continua, such as ultrashort pulses.
To date, most experiments aimed to generate a broad spectral distribution first (e.g. in photonic crystal fibers) and subsequently impose the phase singularity onto the generated white-light beam. Only recently, supercontinuum has been generated directly with an optical vortex beam in calcium fluoride glass.
We have conducted measurements with an optical vortex beam in Argon gas, which serves as a nonlinear Kerr medium. During propagation, inhomogeneities in the beam profile initiate filamentation and supercontinuum generation. Despite strong background beam modulation, the vortex phase is preserved in a broad spectral range.