资源描述：
《(1)T-ray for two_Terahertz waves give rise to a new imaging technique》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、August26,1995BROWSEBROWSETABLEOFBYYEAR1995ISSUESCONTENTS1995Vol.148No.9p.136TRaysforTwoTerahertzwavesgiverisetoanewimagingtechniqueByRICHARDLIPKINTheyhadsetouttoworkonanentirelydifferentproblem.BinBinHuandMartinC.Nuss,twophysicistsatAT&TBellLaboratori
2、esinHolmdel,N.J.,aimedtodevelopabettermethodfortestingtheintegrityofhigh-speedelectricalcircuits.Butnotinghoweasilyterahertzwaves—aformoftrillion-cycle-per-secondradiationthatexistsbetweentheinfraredandradiowaveregionsofthespectrum—penetratethesilicon
3、cir-cuitry,thescientistsbegantowonderaboutmoregeneralapplications.Couldthistechniquebeusedtodeterminethestructuralandchemicalcompositionsofordinaryobjects?Indeeditcan,theysoonconfirmed.ThusemergedanewimagingsystembearingthenameTrays.“Thisisoneofthosec
4、ases,”saysNuss,“wherewesetouttodoonethingandendedupfindingsomethingcompletelydifferentthat’smoreimportant.”“Youcanthinkofterahertzwavesasveryhighfrequencyradiowavesorverylowfrequencyinfraredwaves,”saysNuss.“Thesewaveshavetheinterestingpropertythatthey
5、caneasilypassthroughmanydry,nonmetallicmaterials,likeplastic,cardboard,wood,andglass.”Althoughtheradiationcanpenetrateonlyafewmillimetersintosomematerials,thewavescanpassthroughsufficientlythinsamples,becomingslightlydistortedintheprocess.Byinterpreti
6、ngthechangedwaveformsthatemergefromtheotherside,researcherscanfigureoutthechemicalcompositionofthematerialinquestion.BymeasuringsubtledistortionsoftheTrays,includingabsorption,dispersion,andreflec-tion,scientistscandecodethewaveform“signatures”charact
7、eristicofspecificelements.Conventionalfar-infraredspectroscopyyieldssimilarcompositionalinformation,butitcannotproduceanimage.Inthenewtechnique,acomputerformulatescompositionaldataintoacolorpicture.NussandHufoundthatterahertzwavespassingthroughthefatt
8、yedgesofabaconslice,forexample,comeoutlookingquitedifferentfromthosemakingtheirwaythroughthemeatymiddle.Surprisingly,thesamesignal-processingalgorithmsthatthetelephonecompanydesignedforspeechrecognitionhavecomeinhandyfordecodingterahertzwaves.
