"Spinning electrons with intense circularly polarized pulses to generate circular attosecond pulses - a new tool for electron control."

"The main goal of the new attosecond (asec=10**-18s) science is the visualization, control and manipulation of electrons on their natural time scale, the asec (152 asecs being the orbital period of the H atom). High order harmonic generation (HHG) in atoms and Molecular High Order Harmonic Generation (MHOHG) in molecules driven by intense ultrashort low frequency laser pulses are the current main source of asec pulses.The mechanism for generation of harmonics is based on the three-step model of tunnelling ionization, acceleration and collision-recollision of the ionized electron with parent or neighbour ions [1]. So far only linearly polarized isolated asec pulses have been generated for which the recollision model predicts maximum energies [2]. Current research on asec pulse generation is focused on the polarization state in MHOHG [3]. Modelling of laser-molecule interactions in the nonlinear nonperturbative regime requires extensive (expensive) numerical solutions of Time-Dependent Schroedinger Equations (TDSE) from which one can study recollision dynamics with ultrashort intense circularly polarized laser pulses in order to produce circular asec pulses. Semiclassical models of laser induced recollision allow for determining the effect of various laser parameters such as polarization, intensity and duration of circularly polarized asec pulses. Such pulses due to their large band width will allow for the creation of circular coherent electron wave packets (CEWP), ie, « spinning » electrons. Chemistry and biology have lived through 2 centuries of molecular « structure ». Asec pulses will finally allow scientists to study molecular « function » on the electron`s natural time scale, the asec?"[1] PB Corkum, Physics Today, March 2011,p.16[2] AD Bandrauk, S Chelkowski, Intnl Rev Atom Molec Phys, 2, 1-22 (2011).[3] AD Bandrauk, KJ Yuan, J Phys B, S 45, 074001 (2012)