简介:Inaccordancewithnonperturbativequantumscatteringtheory,weinvestigatephotoelectronangulardistributions(PADs)fromabove-thresholddetachment(ATD)ofnegativeionsirradiatedbycircularlypolarizedfew-cyclelaserfields.Electronsejectedonthepolarizationplanedemonstratedistinctanisotropiesinangulardistributionswhichdistinctlyvarywiththecarrier-envelope(CE)phase.Theanisotropyiscausedbyinterferencebetweentransitionchannels;italsodependsstronglyonlaserfrequency,pulseduration,andkineticenergyofphotoelectrons.Optimalemissionofphotoelectrons,whichvarieswithCEphase,makesitpossibletocontrolphotoelectronmotion.
简介:Thebehaviorofpopulationtransferinanexcited-doubletfour-levelsystemdrivenbylinearpolarizedfew-cycleultrashortlaserpulsesisinvestigatednumerically.Itisshownthatalmostcompletepopulationtransfercanbeachievedevenwhentheadiabaticcriterionisnotfulfilled.Moreover,therobustnessofthisschemeintermsoftheRabifrequenciesandchirpratesofthepulsesisexplored.