Isolated Attosecond Pulse Generation Driven by Spatio-Temporal Pulse Reshaping in a Semi-infinite Gas Cell

High-order harmonic generation (HHG) is an ubiquitous tool of great interest in many fields of research from imaging to ultrafast spectroscopy [1]. In its most common implementation, an intense
$(\approx 10^{14}\ \mathrm{W}/\text{cm}^{2})$
infrared (IR) pulse is focused on a noble gas target yielding a train of attosecond pulses in the extreme ultraviolet (XUV) spectral region. By adopting proper strategies and target geometries, it is possible to isolate an attosecond pulse out of the train. In this work, we demonstrate the generation of isolated attosecond pulses by spatio-temporal reshaping of few-cycle IR driving pulses in a semi-infinite gas cell. We combine numerical simulations and experiments to investigate the interplay between the spatio-temporal reshaping of the driving field, the generation of harmonics and the isolation of an attosecond pulse.