Carrier-envelope-phase-dependent above-threshold ionization of xenon observed with multi-cycle laser pulses

Abstract

Carrier-envelope-phase (CEP)-dependent modulation was measured in above-threshold ionization of xenon driven with 30-fs laser pulses. We showed the dependence from the asymmetry map obtained using a velocity map imaging spectrometer, up to 17 eV in photoelectron energy. The dependence appeared to be linear with a slope of one photon energy increase per CEP change of 2 pi and did not rely on the sign or the amount of laser chirp. Our results indicated the existence of the quantum interference between different multiphoton ionization paths.