Above-threshold ionization in atomic hydrogen using intense, few-cycle laser pulses

The interaction of intense few-cycle light pulses and matter has given rise to a number of high-field physical processes that are of great interest. The high non-linearity of such interactions necessitates complex numerical simulations in order to retrieve useful physical measurements from the experimental data. Here we demonstrate quantitative agreement at the 10% level between experimentally obtained integrated photoelectron spectra and numerical simulations for above-threshold ionization in the intense few-cycle regime. The use of atomic hydrogen provides a key experimental innovation as it is the only electronic system for which ab initio simulations in this regime are available.