Symmetries and Asymmetries in Above-Threshold Ionization

Abstract

Angular distributions of atomic electrons photoionized above threshold by intense elliptically polarized light contain strong asymmetries with respect to reflection about either principal polarization axis.1 These observations, which contradict Keldysh-Faisal-Reiss theory predictions,2,3,4 point to the significant role of the long range electrostatic potential of the ion in shaping the wave function of the outgoing electron. The experimental evidence for this phenomenon is reviewed for helium, krypton, and xenon photoelectron spectra, as a function of laser intensity, polarization, and electron energy.