Full text loading...
Overview of the TEO setup at FLASH. The relative arrival time between electron bunch and NIR pulse is measured inside the accelerator tunnel. (a) The short NIR pulses of a Ti:sapphire oscillator are transported via a single-mode, polarization maintaining glass fiber. (b) Due to a 45° angle of incidence, the transversal position of the polarization modulation inside the optical beam profile depends on the relative arrival time of the NIR pulse and the electron bunch at the EO crystal. When the laser pulse arrives later than the electron bunch, the modulation moves within the transversal beam profile to the left (looking along beam direction) (c) The signal detection is performed in a crossed polarizer setup. The arrival time of the electron bunch is measured shot-by-shot.
Left: photoelectron spectra plotted as function of the pulse number, Right: spectra sorted according to the arrival time determined by TEO. The spectra are background subtracted and averaged over time intervals of 10 fs. The spectral intensity is color encoded. In the arrival time sorted case, two sideband peaks appear. Unsorted no temporal sideband peaks are visible.
An uncorrected pump-probe delay scan (x) of the normalized amplitude of the first order sideband is compared with the TEO sorted sideband amplitude (o) deduced from Fig. 2 and the expected optimal first order sideband signal (–). A Gaussian peak fit of the uncorrected data shows a width of 410 fs rms. For the corrected sideband peak a width of 100 fs rms is found. The ideal peak width would be 53 fs rms. Normalized signal amplitudes are used.
Article metrics loading...