Heidelberg 2015 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 62: Poster: Quantum Optics and Photonics III

Q 62.83: Poster

Thursday, March 26, 2015, 17:00–19:00, C/Foyer

Ultrafast spatial shaping of femtosecond laser beams — •Tom Bolze and Patrick Nuernberger — Physikalische Chemie II, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum

Femtosecond laser pulses and their temporal shaping are widely used in spectroscopy, material science and information technology. Spatial shaping of laser beams has also been demonstrated in multiple ways. However, changing the spatial distribution of a femtosecond pulse on the ultrafast timescale of the pulse itself is rather unexplored up to now.
We present a concept for this task, which involves a Mach-Zehnder-type setup. In one arm, a spiral phase plate transforms the incident Hermite-Gaussian (HG) laser beam into a Laguerre-Gaussian (LG) mode with orbital angular momentum (OAM) and a glass rod chirps the pulse in time. In the second arm, the transverse laser mode remains that of a HG beam and a femtosecond pulse shaper imprints the same amount of chirp but with the opposite sign onto the pulse. The beams from both interferometer arms are then recombined. The interference should resemble a corkscrew like motion of the intensity distribution around the beam axis on the timescale of the pulse. This can be visualized via a third "gate" pulse with perpendicular polarization which upconverts the spatial intensity distribution.