Charakterisierung von Laser-Bursts durch Spektrograph mit MHz-Ausleserate

The Free Electron Laser in Hamburg FLASH provides short X-Ray and ultraviolet pulses with high repetition rates in bursts. Optical laser systems create synchronized bursts in various wavelength ranges for pump-probe-experiments. The non-linear effect self-phase modulation is used for the generation of short pulses by spectral broadening in multi-pass cells. It couples intensity and resulting pulse spectra. The strength of non-linear effects depends on varying beam properties and pulse energies over the burst.In this bachelor thesis a spectrograph is set up and calibrated for a central wavelength of 1030nm where the usage of the new linear array detector KALYPSO allows to read out single spectra with MHz rates to monitor spectral intra-burst dynamics. Bandwidth and central wavelength are calculated for all spectra and compared with the variation of the pulse peak-intensities of the burst.For the FLASH2 pump-probe laser such a measurement is now possible for the first time at all. As expected, the spectral broadening inside the burst scales linear with the energy of the single pulses. The changes in the self-phase modulated spectra over the burst duration are compared with the changes of the beam profile. At a different laser, which corresponds to the new burst-mode laser at FLASH1, the influence of thermal lenses on spectral broadening was analyzed. The present state of the detectors development did not allow an unambiguous conclusion regarding the expected relation there. Nevertheless it was possible to frame the further proceedings in using the device. To achieve better comparability of the data, the readout electronics of the detector should be checked and its spectral sensitivity ought to be determined.Even if a precise readout of spectra with MHz rates could not be proved so-far, it was possible to formulate first statements regarding the impact of the non-linear effects on the burst and the contained pulse spectra with the used KALYPSO-spectrograph. Therefore, the device is a promising new diagnosis tool for the optical burst-mode lasers at FLASH which in the future can be used for measurements of visible and ultraviolet spectra