Reduced ground state depletion in the high order harmonic generation process through spectral phase pulse shaping*

High order harmonic generation (HHG) is an important process in attosecond physics, where it is used to generate attosecond pulse trains and single attosecond pulses for the observation of nuclear and electronic motion. During the HHG process, an intense laser pulse tunnel ionizes an electron, after which the electron moves in the laser field, and eventually recombines with the atom. Recombination results in light of harmonic frequencies of the laser field being emitted. Improved control of the HHG process is desirable, and one such possibility for this control is through the use of structured laser pulses, such as Airy pulses. We present numerical results for solving the 1D time-dependent Schrödinger equation and a classical model for HHG from argon using Airy and Gaussian pulses. We show that differences in the harmonic spectrum, emission times, and state populations are observed for Airy pulses compared to Gaussian pulses. We demonstrate that Airy pulses with small third order spectral phase terms result in less ground state depletion of the atom, while maintaining the harmonic cutoff energy. For Airy pulses with large third order spectral phase terms, the harmonic cutoff energy was decreased due to a reduced pondermotive energy of the electron in the laser field.