1,721,168 research outputs found
Pulse characterization by THG d-scan in absorbing nonlinear media
No full textWe report on few-cycle pulse characterization based on third harmonic generation dispersion scan (THG d-scan) measurements using thin films of different TiO2-SiO2 compositions as nonlinear media. By changing the TiO2 concentration in the thin film the band gap and therefore the position of the absorption edge were varied. The retrieved pulse durations from different nonlinear media agree within 5%, and the reconstructed pulse shapes prove to be immune against the absorption edges as well. The reason is the robust retrieval algorithm which takes the influence of wavelength dependent nonlinearity into account by a spectral weight function. (c) 2014 Optical Society of Americ
Impact of spatial inhomogeneities on on-axis pulse reconstruction in femtosecond filaments
Full text linkWe demonstrate a strong influence of the spatial beam profile on the vacuum-propagated on-axis pulse shapes for a femtosecond filament in argon. The effects can be minimized by transmitting the filament into the far-field by a laser-drilled pinhole setup. Using this method, we can monitor the pulse compression dynamics along the entire longitudinal extension of the filament, including the ionization-induced plasma channel
Direct observation of pulse dynamics and self-compression along a femtosecond filament
No full textWe report on the direct experimental observation of pulse-splitting dynamics along a femtosecond filament. The fundamental pulse experiences a significant self-shortening during the propagation leading to pulse durations of 5.3 fs, corresponding to sub-3 cycles, which is measured without external pulse compression. A compression factor of eight could be achieved in a single filamentary stage. Theoretical modeling of the fundamental pulse propagation confirms our observed pulse structures and durations and gives further insight into the nonlinear dynamics during filamentation. (C) 2014 Optical Society of Americ
Few-cycle optical pulse characterization via cross-polarized wave generation dispersion scan technique
No full textWe demonstrate a dispersion scan (d-scan) pulse characterization scheme employing cross-polarized wave (XPW) generation as a nonlinear optical process. XPW generation is a degenerate four-wave mixing process with no phase-matching limitations. Therefore, its implementation in the d-scan method is a good choice for the characterization of few-cycle pulses in remote spectral regions. We fully characterize 5-10 fs pulses delivered through a hollow-core fiber in the near-IR region and compare the results with the second-harmonic generation (SHG) frequency-resolved optical gating and SHG d-scan characterization methods. (C) 2016 Optical Society of Americ
Untersuchungen an oxidischen und oxifluoridischen Materialmischungen zur Optimierung von ionenstrahlgesputterten Dünnschichtsystemen für Hochleistungslaserkompenten
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Fiber amplifiers at 1.5 [my]m for gravitational wave detectors : power scaling, gain dynamics, and pump sources
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