Quasi single-shot two-pulse tilted pulse front autocorrelator coupled with spatial chirp and spectral divergence monitor for ultrashort pulsed laser beams

Abstract

Simultaneous single-shot unambiguous detection and measurement of pulse front tilt, spatial chirp, spectral divergence and pulse width has been carried out using two-pulse tilted pulse-front autocorrelator (TP-TPFAC) coupled with spectral interferometry using small part of laser beam intercepted from Mach Zehnder delay unit of TP-TPFAC generating two delayed and spatially inverted pulses. Error in estimation of rotation angle of autocorrelation (AC) trace due to accidental improper positioning of CCD detector is avoided by measuring angle between AC traces corresponding to two delayed and spatially inverted pulses. Likewise, accuracy in estimation of spatial chirp is improved by using spatially resolved spectral trace of two spatially inverted pulses, as errors due to accidental improper positioning of either grating of spectrograph or CCD detector are avoided. Sensitivities and accuracies of the two methods are compared in different experimental situations. Estimated pulse parameters are found in close accordance with respective theoretical values.