Characterization of an OPCPA laser system by using frequency resolved optical gating and acousto-optic modulation
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This thesis provides a characterization of an optical parametric chirped pulse amplification (OPCPA) laser system by applying several diagnostic techniques. The laser system is operated in low energy modus and each component is optimized. New nonlinear birefringent crystals for optical parametric amplification (OPA) are installed. Measurements to obtain spatial profiles, intensity spectra and energy stability are performed. Best compression is verified by using autocorrelation of the compressed pulse. A frequency resolved optical gating (FROG) device based on second-harmonic generation (SHG) is designed, implemented in the OPCPA laser system and experimentally tested. SHG-FROG traces of high temporal symmetry and low noise are obtained. An inversion code, based on the principle component generalized projection algorithm (PCGPA), is used to obtain full characterization of the compressed laser pulse in the time and frequency domain. An acousto-optic modulator (AOM) is implemented in the OPCPA alignment. The amplitude and the phase of the laser pulse is modulated prior to stretching and the FROG technique is used to observe the consequences for the process of OPCPA. A potential solution to reduce gain narrowing, which occurs in the system's glass rod amplifiers, is found and characterized.