简介:WedescribeandexperimentallydemonstrateameasuringtechniqueforMach–Zehnderinterferometer(MZI)basedintegratedphotonicbiochemicalsensors.OurtechniqueisbasedonthedirectmeasurementofphasechangesbetweenthearmsoftheMZI,achievedbysignalmodulationononeofthearmsoftheinterferometertogetherwithpseudoheterodynedetection,anditallowsustoavoidtheuseofcostlyequipmentsuchastunablelightsourcesorspectrumanalyzers.Theobtainedoutputsignalisintrinsicallyindependentofwavelength,powervariations,andglobalthermalvariations,makingitextremelyrobustandadequateforuseinrealconditions.Usingasilicon-on-insulatorMZI,wedemonstratethereal-timemonitoringofrefractiveindexvariationsandachieveadetectionlimitof4.1×10-6refractiveindexunits(RIU).
简介:Facileproductionofhighqualityactivatedcarbonsfrombiomassmaterialshasgreatlytriggeredmuchattentionpresently.Inthispaper,aseriesofinterconnectedporouscarbonmaterialsfromlotusrootshellsbiomassarepreparedviasimplepyrolysisandfollowedbyaKOHactivationprocess.Thepreparedcarbonsexhibithighspecificsurfaceareasofupto2961m~2/gandlargeporevolume~1.47cm3/g.Inaddition,theresultantporouscarbonsservedaselectrodematerialsinsupercapacitorexhibithighspecificcapacitanceandoutstandingrecyclingstabilityandhighenergydensity.Inparticular,theirspecificcapacitanceretentionwasalmost100%after10500cyclesatacurrentdensityof2A/g.Remarkabely,theimpactofthetailoredspecificsurfaceareasofvariouscarbonsamplesontheircapacitiveperformancesissystematicallyinvestigated.Generally,itwasbelievedthatthehighly-developedporosityfeatures(includingsurfaceareasandporevolumeandporesize-distributions),togetherwiththegoodconductivityofactivatedcarbonspecies,playakeyroleineffectivelyimprovingthestorageenergyperformancesoftheporouscarbonelectrodematerialsinsupercapacitor.