High Intensity Kapitza-Dirac effect.
01 January 1988
Low energy (20 eV) free electrons produced in above-threshold ionization have been scattered by an intense optical standing wave (the Kapitza-Dirac effect). At intensities of 10 sup (13) to 10 sup (14) W/cm sup 2 there is very high momentum transfer between the standing wave "lattice" and the electrons (DELTA rho~1000 hbarK). In this regime, the scattering rate approaches the optical frequency, and the electron motion is most easily analyzed by classical mechanics.