Side rings in doubly differential momentum distribution for midinfrared photoionization

M. DRAN; D. G. ARBÓ

Budapest

Conferencia; The International Conference on Many Particle Spectroscopy of Atoms, Molecules, Clusters and Surfaces; 2018

EKHO' 94 Ltd., Debrecen

Moiré patterns appear in a myriad of situations not only in physics and mathematics but also in diverse disciplines such as art, fashion, digital photography and television [1,2]. For moiré interference pattern to appear, two slightly different patterns or grids must be present. Photoelectron spectra have been described in the literature as an interference problem in the time domain. Trajectories stemming from different optical laser cycles give rise to intercycle interference energy peaks known as multiphoton (or ATI) peaks. Besides, another structure comes from the intracycle interference of the electron trajectories born during the same optical cycle [3]. These two interference patterns form two grids with different momentum-dependent spacing. Moreover, all sets of data possess also an intrinsic numerical grid due to the finite storage capability. We theoretically investigate on the origin of lateral ring structures in the doubly differential momentum distribution for atomic ionization by laser pulses in the midinfrared spectral region [4]. We demonstrate that such structures stems from the interplay between intra- and intercycle interference patterns which work as two separate grids in the two-dimensional momentum domain. When the periods of the two grids (intra- and intercycle) are similar, moiré patterns arise as concentric rings at high electron kinetic energy in the forward and backward directions.