简介:Highharmonicgenerationingasjetswasinvestigatedindifferentgasesuptomorethan14barbackingpressure.TheobservationofincreaseofharmonicintensitywithincreasingpressureandlaserintensityshowsevidenceofthepresenceofclustersinXewithanincreasedefficiencycomparedwithHe,whereasArisanintermediatecaseforwhichclusterswillstarttodominateaboveacertainbackingpressure.Spectralinvestigationsgiveevidencefortunableharmonicgenerationinabroadspectralrange.Aspectralshiftofoppositesignaturecausedbythefreeelectronsinthefocalvolumeandthenanoplasmasinsidetheclusterwasobserved.