简介:Fusionofsyntheticapertureradar(SAR)andforwardlookinginfrared(FLIR)imagesisanimportantsubjectforaerospaceandsensorsurveillance.ThispaperpresentsaschemetoachieveanaturalcolorimagebasedonthecontoursfeatureofSARandthetargetregionfeatureofFLIRsothattheoverallscenerecognitionandsituationalawarenesscanbeimproved.TheSARandFLIRimagesarefirstdecomposedintosteerablepyramids,andthecontourmapsintheSARimageandtheregionmapsintheFLIRimagearecalculated.Thecontourandregionfeaturesarefusedateachlevelofthesteerablepyramids.Acolorimageisthenformedbytransferringdaytimecolortothemonochromicimagebyusingthenaturalcolortransfertechnique.ExperimentalresultsshowthattheproposedmethodiseffectiveinprovidingacolorfusionofSARandFLIRimages.
简介:Micro-depositionofanaluminumfilmof500-nmthicknessonaquartzsubstratewasdemonstratedbylaser-inducedforwardtransfer(LIFT)usingafemtosecondlaserpulse.Withthehelpofatomicforcemicroscopy(AFM)andscanningelectronmicroscopy(SEM),thedependenceofthemorphologyofdepositedaluminumfilmontheirradiatedlaserpulseenergywasinvestigated.Asthelaserfluencewasslightlyabovethethresholdfluence,thehigherpressureofplasmaforthethickerfilmmadethefreesurfaceofsolidphaseburstout,whichresultedinthatnotonlythesolidmaterialwassputteredbutalsothedepositedfilmintheliquidstatewasmadeirregularly.
简介:Asimpleapproachbasedonsixtransfercellsandsimulatedannealingalgorithmforanalyzingandtailoringthespectraofarbitrarymicroringresonatorarraysispresented.Couplingcoefficients,ringsizes,andwaveguidelengthsofmicroringresonatorarrayscanbearbitraryinthisapproach.Afterdevelopingthisapproach,severalexamplesaredemonstratedandoptimizedforvariousconfigurationsofmicroringresonatorarrays.Simulationresultsshowthatthisapproachisintuitive,efficient,andintelligentforapplicationsbasedonmicroringresonatorarrays.
简介:Thebehaviorofpopulationtransferinanexcited-doubletfour-levelsystemdrivenbylinearpolarizedfew-cycleultrashortlaserpulsesisinvestigatednumerically.Itisshownthatalmostcompletepopulationtransfercanbeachievedevenwhentheadiabaticcriterionisnotfulfilled.Moreover,therobustnessofthisschemeintermsoftheRabifrequenciesandchirpratesofthepulsesisexplored.
简介:Enhanced2.7μmemissionisobtainedinEr3+/Tm3+andEr3+/Ho3+codopedZBYAglasses.Absorptionandemissionspectraaretestedtocharacterizethe2.7μmemissionpropertiesofEr3+/Tm3+andEr3+/Ho3+dopedZBYAglassesandareasonableenergytransfermechanismof2.7μmemissionbetweenEr3+andTm3+Ho3+)ionisproposed.CodopingofTm3+orHo3+significantlyreducesthelifetimeoftheEr3+:4I13/2levelduetotheenergytransferofEr3+:4I13/2→Tm3+:3F4orEr3+:4I13/2→Ho3+:5I7.Thus,the2.7μmemissionisstrengthenedandthe1.5μmemissionisdecreasedaccordinglyespeciallyintheEr3+/Tm3+sample.TheupconversioneffectsbetweentheEr3+/Tm3+andEr3+/Ho3+dopedZBYAglassesaredifferentattributetothedifferentenergytransferefficiencies.Bothofthetwocodopedsamplespossessnearlyequallargeemissioncrosssection(16.6×10-21cm-2)around2.7μm.TheresultsindicatethatthisEr3+/Tm3+orEr3+/Ho3+dopedZBYAglasshaspotentialapplicationsin2.7μmlaser.