简介:Wereportontheamplificationofhigh-average-powerandhigh-efficiencypicosecondpulsesinaself-madeverylarge-mode-areaYb-dopedphotoniccrystalfiber(PCF).ThePCFwithacorediameterof105μmandacorenumericalapertureof0.05ispreparedbythesol-gelmethodcombinedwiththepowdersinteringtechnique.Thefiberamplificationsystemproducesthehighestaveragepowerof255Wata10MHzrepetitionratewitha21pspulsedurationcorrespondingtoapeakpowerof1.2MW.Thisresultexemplifiesthehigh-average-powerandhigh-peak-powerpotentialofthisspecificallydesignedfiber.
简介:Totalcrosssections(TCSs)ofelectronsscatteringfromtriatomicmoleculesovertheenergyrangefrom30to5000eVareinvestigatedemployinganewsemi-empiricalformula.TheTCSsofelectronsscatteringfromtriatomicmoleculesSO2,NO2,andCO2arecalculated.ThequantitativeTCSsareingoodagreementwiththoseobtainedbyexperiments.Itisshownthattheresultsderivedfromthesemi-empiricalformulaaremuchclosertothemeasurementsthanothercalculations.