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Q: Fachverband Quantenoptik und Photonik
Q 5: Ultrakurze Laserpulse: Erzeugung 1
Q 5.6: Vortrag
Montag, 12. März 2012, 11:45–12:00, V38.01
Carrier-envelope phase stable sub-two-cycle pulses tunable around 1.8 µm at 100 kHz — Christian Homann1, •Maximilian Bradler1, Michael Förster2, Peter Hommelhoff2, and Eberhard Riedle1 — 1BioMolekulare Optik, LMU München — 2Ultrafast Quantum Optics Group, MPI für Quantenoptik, Garching
We present a simple and efficient concept for the generation of ultrashort infrared pulses with passively stabilized carrier-envelope phase at 100 kHz repetition rate. The central wavelength is tunable between 1.6 and 2.0 µm with pulse durations between 8.2 and 12.8 fs corresponding to a sub-two-cycle duration over the whole tuning range. Pulse energies of up to 145 nJ are achieved. As a first step tunable 10 fs visible pulses are generated by noncollinear optical parametric amplification of a continuum seed, both pumped by the 300 fs pulses of commercial Yb:KYW based disk laser. These intermediate pulses are compressed in a fused silica prism compressor. For the NIR generation difference frequency mixing in a 800 µm thick BBO crystal the residual fundamental light is used. The CEP stability is measured to 78.5 mrad (1 ms integration) in a f-2f interferometer. For the necessary broadening of the pulses beyond one octave, we use a highly nonlinear fiber. With the proper setting of the visible compressor the NIR pulses are nearly perfectly compressed as seen from a FROG measurement. As a first application we measure the high non-linearity of multiphoton photoemission from a nanoscale metal tip. The high repetition rate and the sub-2 cycle pulse length should make this new source widely useful in extreme ultrafast studies.