Modulation of cross-correlation traces by pulse-shaping with spatial mask

Abstract

Femtosecond laser pulses with desired complex shapes have been exploited to 'steer' the dynamics of various light - matter interaction processes, ranging from second-harmonic generation to control of the products in various chemical reactions. This has been achieved by modulating many parameters within the pulses both in time domain as well as in frequency domain, the latter being done using a pulse-shaper. Here we report the construction of a simple pulse-shaper with 4f zero-dispersion geometry. We used a thin glass plate (and a neutral density filter) to give a phase delay (and intensity attenuation) to various spectral components of a pulse centred at 1560 nm produced by a fibre-laser. The cross-correlation traces of this pulse with another pulse centred at 780 nm from the same laser were studied under different phase (and amplitude)- modulating conditions of the former pulse. The pulse-shaping results in complex shapes in the cross-correlation traces, which can be exploited in the study of coherent light-matter interactions.