High-Order Above Threshold Ionization of Noble Gas Atoms using Sculpted Laser Pulses

We present theoretical simulations of above threshold ionization (ATI) of noble gas atoms using sculpted laser pulses. The time-dependent Schrödinger equation is solved to calculate the ATI energy and momentum spectra, and a classical model that solves Newton’s equations of motion provides a qualitative understanding of the electron motion after ionization. Results are presented for Gaussian and Airy laser pulses with identical power spectra, but differing spectral phases. The simulations show that the third order spectral phase of the Airy pulse causes changes to the timing of ionization and the dynamics of the rescattering process. Specifically, the use of Airy pulses in the ATI process results in a shift of the Keldysh plateau cutoff to lower energy due to a decreased pondermotive energy of the electron in the laser field. Additionally, the number and timing of rescattering events is altered due to the side lobes of the Airy laser pulse, resulting in changes to the high-order ATI plateau. Our results also show that laser pulses with identical carrier envelope phases, and nearly identical envelopes, yield different photoelectron momentum densities, which are a direct result of the pulse’s spectral phase.