简介:Organicmultiplequantumwells(OMQWs)consistingofalternatinglayersoforganicmaterialshavebeenfabricatedfromtris(8-hdroxyquinoline)aluminum(Alq)and2-(4-biphenylyl)-5-(4-tertbutylphenyl)-1,3,3-oxadiazole(PBD)byamultisource-typehigh-vacuumorganicmoleculardeposition.Fromthesmall-angleX-raydiffractionpatternsofAlq/PBDOMQWs,aperiodicallylayeredstructureisconfirmedthroughtheentirestack.TheAlqlayerthicknessintheOMQWswasvariedfrom1nmto4nm.Fromtheopticalaborption,photoluminescenceandelectroluminescencemeasurements,itisfoundthattheexcitonenergyshiftstohigherenergywithdecreasingAlqlayerthickness,ThechangesoftheexcitonenergycouldbeinterpretedastheconfinementeffectsofexcitonintheAlqthinlayers.Narrowingoftheemissionspectrumhasalsobeenobservedfortheelectroluminescentdevices(ELDs)withtheOMQWsstructureatroomtemperature.
简介:"2004清洗技术国际论坛暨清洗技术装备展览会"再过2个月即将在上海光大会展中心隆重开幕.上海是一个工业非常发达的城市,工业发展具有很多优势条件:首先,上海有着坚实的工业基础和雄厚的技术实力,而且作为世界级的国际大都市,她还有着无与伦比的工业发展综合优势,如:发达的基础设施和广泛的人才优势.目前上海利用外资的势头不减,世界五百强企业的亚洲总部竞相落足上海.上海已成为全球最重要的国际会展中心之一,是国际性大企业竞相展示自己实力的重要舞台,国际展会经年不断.今年的清洗技术国际论坛暨清洗技术装备展览会在上海举行可谓占尽天时、地利.作为主办单位,我们怀着激动的心情热切盼望展会的到来.
简介:ThecrystallographicpropertiesandRamanspectraofthetitlecompoundZnCd(SCN)4,whichisanewnonlinearopticalcrystal(NLO),arereportedforthefirsttime,ThiscrystalisorthorhombicanditsspacegroupisI4^4withunitcellparametersa=1.135(0.2)nmc=0.43760(1)nm.Therearetwoformulasperunitcell.Ramanspectraofzinccadmiumthiocyanatec(ZCTC)aregivenandtheelectronactivitiesinthecrystalareshown.
简介:AnewlygrownBaGa4Se7crystalhasbeensynthesizedviatheBridgman-Stockbargertechnique.Thisnewcrystalhasadvantagesofhighnonlinearoptics(NLO)coefficients,highlaserdamagethresholds,andwidetransparentregions.TheBaGa4Se7crystalhasbrightapplicationprospectsasanonlineargainmediuminmid-infraredandterahertzregions.Inthispaper,thecrystallinestructureandsyntheticmethodoftheBaGa4Se7crystalareintroduced.Therefractiveindicesandabsorptioncoefficientsalongthreedielectricaxesbetween0.1THzand1.0THzarealsoobtained.Theterahertzdifferencefrequencygeneration(THz-DFG)characteristicsbasedontheBaGa4Se7crystalinthefrequencyrangeof0.1THzto1.0THzareanalyzedtheoreticallyandthephase-matchingconditionsarecalculated.TheapplicationofBaGa4Se7crystalsinterahertzwavegenerationisalsodiscussed.
简介:Thestabilityofthedrivecurrentisveryimportantforalaserdriver,whileitisdifficulttomaintainthecurrentstableatahighvalueforthelaserdriver.Ontheotherhand,therangeofthedrivecurrentisexpectedtobeaswideaspossibletobeappliedtodifferentkindsoflasers.Inthispaper,ahighcurrentlaserdriverforthesuperluminescentlightemittingdiode(SLED)ispresented,whichisusedintheopticfibergyroembeddedbya0.35mbipolarcomplementarymetal-oxide-semiconductortransistor(BiCMOS)process.Thelaserdriverprovidesautomaticpowercontrolandcertainvalueofcurrentdeterminedbytheexternalresister.Thesystemisbasedontheoptic-electricfeedbacktheoryandusestheclosed-loopcontroltechniquetomaintainthedrivecurrentstable.Thesystemiscapableofproducingstablecurrentrangesfrom4mAto200mAwhenthevalueofexternalresisterchanges.