Role of the absolute-phase in photoionization with few-cycle laser pulses

Summary form only given. In this work we have employed a technique which allows us to demonstrate experimentally the influence of the absolute phase on photoelectron emission. Photoionization of atoms in intense laser fields is characterized by above-threshold ionization (ATI). Using long pulses the angular distribution of emitted photoelectrons has inversion symmetry, since the electric field of long pulses exhibits such a symmetry. For ultrashort pulses, depending on the absolute phase, the generation of photoelectrons violates inversion symmetry. The absolute phase is thus expected to cause an anticorrelation in the number of electrons escaping in opposite directions, if these are investigated shot by shot.