Osnabrück 2002 – scientific programme

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MO: Molekülphysik

MO 21: Femtosekundenspektroskopie VIII: Pulserzeugung und Phasenkontrolle (gemeinsam mit FV Q)

MO 21.7: Talk

Friday, March 8, 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.