Photoionization dynamics in intense few-cycle twisted laser pulses

Electrons emitted during photoionization provide key insights into light-atom interactions. While conventional laser pulses have been widely studied, the effects of structured light fields, particularly twisted Bessel beams with orbital angular momentum, remain less explored. Previous research has shown that spectral peaks in above-threshold ionization shift with changes in the opening angle and orbital angular momentum of Bessel pulse. However, the precise impact and sensitivity of these parameters on photoelectron momentum distributions (PMD) is still unclear. In this paper, we use the strong-field approximation and saddle-point method to analytically derive the ionization transition amplitude for these pulses. For computational simplicity, we model the atomic target using a hydrogenic 1s orbital wave function, with parameters adapted for krypton to capture the essential ionization dynamics. This allows us to compute the PMD while resolving the effects of both the opening angle and orbital angular momentum.