简介：Weobserveanonlinearresponseofadual-wavelengthNd:YAGlaserwhensubjectedtolow-frequencyperiodicmodulationsofcavitylosses.Themodulationfrequencyisfarfromtherelaxationoscillationfrequency.Theharmonicresonancesofthetwolaserwavelengthsassociatedwithantiphaseintensityoscillationsaredemonstratedandresonancesuptothefourthorderwereobserved.Forrelativelyweakmodulation,theintensityoscillationfrequencyofthelaserisequaltothemodulationfrequency.Harmonicresonancesoccurunderastrongermodulation.Wefindthatmoreharmoniccomponentsappearwhenthemodulationfrequencyisincreased.Furthermore,withenhancingthemodulation,thedominantfrequencyoftheintensityoscillationsofbothwavelengthsisshiftedtowardthehigher-orderharmonicfrequency.更多还原

简介：Ablationdynamicsoftungstenirradiatedwitha70fslaserpulseisinvestigatedwithX-rayinterferometryandX-rayimagingusinga13.9nmsoftX-raylaserof7pspulseduration.Theevolutionofhigh-densityablationfrontoftungsten(i.e.,W)ispresented.Theablationfrontexpandsto～120nmabovetheoriginaltargetsurfaceat160psafterfemtosecond-laserirradiationwithanexpansionspeedofapproximately750m∕s.TheseresultswillprovideimportantdataforunderstandingablationpropertiesofW,whichisacandidatematerialofthefirstwallofmagneticconfinementfusionreactors.