简介:WeinvestigatereactivefluorineatomspectroscopiccharacterizationinatmosphericpressureofHe/SF6plasmausingatomicemissionspectrometry.Asinputradiofrequency(RF)powerlevelsareraisedfrom140to220W,theemissionspectraof685.60(3p4D→3s4Ptransition)and739.87nm(3p4P→3s4Ptransition)increasesignificantly.Moreover,anoptimalvalueofSF6volumeconcentrationintheproductionoffluorineradicals,whichis0.8%isachieved.AdditionofcertainamountsofO2intoHe/SF6plasmaresultsinthepromotionofSF6dissociation.EmissionintensitiesoffluorineatomsshowthemaximumattheO2/SF6ratioof0.4.
简介:Wereportthefabricationofsubmicrometerpitsarray(SP-array)on6H-SiCsurfacebytheinterferenceoftwofemtosecondlaserbeams.FormationmechanismsandopticalabsorptionofSP-arrayarestudied.Therelativereflectivityandtransmissivityofwhitelightdecreaseto10%ofthevaluesofSiCcrystal,andtheopticalabsorptionisenhancedto97%.Therelativereflectivityandtransmissivityofincidentangleswithintherangeof20°-60°arekeptbelow25%.TheenhancementmechanismofopticalabsorptionoftheSP-arrayisalsodiscussed.
简介:Metamaterials因其在特定频段内同时满足负的介电常数和负磁导率而具有与常规介质不同的电磁特性,该电磁特性与Metamaterials的结构密切相关。分析了线环结构的结构参数与其电磁特性的关系,在此基础上提出了一种方形环结构设计。仿真结果表明,方形环结构可以同时满足负的介电常数和负磁导率,具有负折射特性,而且具有比线环结构更宽的带宽。