Charakterisierung der nichtlinearen Pulspropagation in einer gasgefüllten Hohlfaser

In this work, the propagation of ultrashort laser pulses in a hollow fiber filled with helium has been investigated. The spectral evolution along the fiber is numerically simulated and compared to the measurements. The simulations, which are based on a one-dimensional propagation equation, allow us to identify and characterize the underlying nonlinear effects. In order to verify these results experimentally, a spectrometer was designed, set up and implemented into a state-of-the-art femtosecond laser system. The analysis concerning the spectral width shows a linear dependency on the pressure inside the fiber. By optimizing this spectral broadening, shorter and shorter pulse durations can be reached, enabling the access to information about physical processes on even shorter time scales