The heart of the setup is a hybrid laser system which was built at Chair Leitenstorfer. An erbium-doped fiber oscillator emits pulses with a duration of 110 fs at a repetition rate of 48.9 MHz. The central wavelength is 1550 nm at a pulse energy of 70 pJ. The pulses are synchronously amplified by two erbium-fiber amplifiers. The pulse of the first branch is spectrally broadened in a highly nonlinear glass fiber. Subsequently, the pulse duration is significantly reduced by a prism compressor. It is used as sample pulse in the EOS setup. The amplified pulse of the second branch is used as seed for the Ti:sapphire laser amplifier. Before the pulse is coupled into the amplifier, it is frequency doubled to a wavelength of 775 nm. This wavelength matches well with the center of the amplification bandwidth of the Ti:sapphire crystal. The Ti:sapphire amplifier itself is the commercial system "Spitfire Pro XP 5W" by Spectra Physics with a 1 kHz repetition rate. The output pulse has an energy of up to 5 mJ and a pulse duration of 120 fs. To ensure a stable operation, the system is temporally and spatially stabilized which offers the possibility to average the measuring signals over a long period of time.