Photoelectron spectra of gas target in circular polarization intense laser field

Abstract

We investigate photoionization spectra of gas target with intense light field by using time-of-flight spectrometer. It was found that photoelectron spectra of Kr gas have tail structure in both circular and linear polarization light. It is well known that the tail structure is caused by recollision in case of linear light field. Nevertheless it was believed that recollision is suppressed in circular polarization light. In recent works, it was reported that a few percent of continuum photoelectron wave packet may return to ion core in circular polarization field, by assuming of initial momentum distribution of electron. The tail structure by circular polarization light implies that recollision may contribute to photoionization despite circular polarization light.