Osnabrück 2002 – wissenschaftliches Programm
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MO: Molekülphysik
MO 21: Femtosekundenspektroskopie VIII: Pulserzeugung und Phasenkontrolle (gemeinsam mit FV Q)
MO 21.7: Vortrag
Freitag, 8. März 2002, 15:30–15:45, HS 15/E07
Electronic timing control of independent femtosecond lasers — •nils haverkamp1, joern stenger1, harald r. telle1, carsten fallnich2, and holger hundertmark2 — 1Phys.-Tech. Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany — 2Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germnay
We report on fsec-pulse synchronization at arbitrary relative delays by purely electronic means. Thereby we avoid geometric delay lines, which may alter beam parameters, which in turn may be detrimental in pump-probe-experiments. The pulses are generated by a Kerr-lens modelocked Ti:Sa-Laser (repetition rate 100MHz, pulse duration 10fsec, center wavelength 780nm) and an Er:fiber-laser (60MHz, 50fsec, 1560nm). We chose lasers differing in repetition rate and spectral region of emission to show general applicability. Pulse-synchronization is achieved by detection and phase-locking of high harmonics of the repetition rate in the micro-wave region. We introduce tunable phase-offsets of arbitrary magnitude in the phase-lock-loop and thereby control the relative delay between pulses from the two lasers.
In combination with a short BBO-crystal the ultrashort Ti:Sa-pulses allow for precise determination of infrared-pulse shapes with a time-resolution below 20fsec via cross-correlation, e.g. for investigation of pulse- distortion and soliton formation in dispersive media.