Moiré patterns in momentum maps for atomic photoionization

D. G. ARBÓ; M. DRAN

Encuentro; I Encuentro Nacional de Dinámica Cuántica de la Materia; 2019

We theoretically investigate on the origin oflateral ring structures in the doubly differentialmomentum distribution for atomic ionization bylaser pulses in the midinfrared spectral region.Moiré patterns appear in a myriad of situations notonly in physics and mathematics but also in diversedisciplines such as art, fashion, digital photographyand television [1]. For moiré interference pattern toappear, two slightly different patterns or grids mustbe present.Photoelectron spectra have been described inthe literature as an interference problem in the timedomain. Trajectories stemming from differentoptical laser cycles give rise to intercycleinterference energy peaks known as multiphoton(or ATI) peaks. Besides, another structure comesfrom the intracycle interference of the electrontrajectories born during the same optical cycle [2].These two interference patterns form two gridswith different momentum-dependent spacing.We theoretically investigate on the origin oflateral ring structures in the doubly differentialmomentum distribution for atomic ionization bylaser pulses in the midinfrared spectral region [3].We demonstrate that such structures stems fromthe interplay between intra- and intercycleinterference patterns which work as two separategrids in the two-dimensional momentum domain.When the periods of the two grids (intra- andintercycle) are similar, moiré patterns arise asconcentric rings at high electron kinetic energy inthe forward and backward directions