Hamburg 2009 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 15: Ultrakurze Pulse: Erzeugung III

Q 15.2: Talk

Tuesday, March 3, 2009, 10:45–11:00, Audi-A

Generation, Phase modulation and Characterization of femtosecond UV pulses — •Jens Möhring, Tiago Buckup, and Marcus Motzkus — Physikalische Chemie, Universität Marburg, Hans-Meerwein-Straße, D-35032 Marburg

The extension of coherent control in the UV requires a flexible, ultrashort source of phase modulated pulses. To cover molecular systems absorbing in this spectral range we present an improved setup around our micromechanical, direct UV femtosecond spatial light modulator. The possibility of combined phase and amplitude modulation, an optimized duty cycle and a simple pulse characterization upgrades significantly the shaping setup for coherent control. The applied sub 30 fs UV pulses, tunable between 300 to 350 nm, are generated by sum frequency mixing of a noncollinear parametric amplifier with NIR pulses. Phase modulation based on a 2D micro mirror array enables then full phase control directly in the UV. Diffractive shaping on this 2D MEMS (micro electromecanical System) device makes possible amplitude control on a phase only modulator by exploiting two dimensional phase structures. In addition, a simple UV autocorrelator based on two photon absorption in a solar blind photomultiplier tube, was constructed. The combination of diffractive shaping and the autocorrelator setup facilitates powerful cross correlation techniques to characterize e.g. linear time delays and double pulse structures.