信息获取技术和材料

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1、获取信息的技术和材料获取信息主要使用探测器和传感器。目前光电子学技术是或取信息的主要手段光电探测器按光电转换方式，光电探测器可分为:光电导型、光生伏打型（势垒型）和热电偶型。光电转换中根据探测的光子波长分为:狭能隙半导体材料（红外）和宽能隙半导体材料（可见和紫外）。宽能隙材料以Si、Ge、和GaN、AlN等为主，狭能隙半导体材料主要为铅盐、碲镉汞、SbIn等。近期光电探测器最大的进展在两个方面：(1)用超晶格（量子阱）结构提高了量子效率、相应时间和集成度；（2）制成了探测器阵，可以用作成像探测。两者结合后最典型的例子为可以制成探

2、测灵敏度极高的HgCdTe红外焦平面列阵（FPA），并成功地应用于红外遥感、成像等。Photodetector:convertlightintoelectricitythroughthephotoelctriceffectRequirements:highsensitivity,fastresponse,lownoise,lowcost,andhighreliabilityRistheresponsivityofthephotodetector(A/W)thebandwidthofaphotodetectorisdetermin

3、edbythespeedwithwhichitrespondstovariationsintheincidentopticalpower.TherisetimeTrisdefinedasthetimeoverwhichthecurrentbuildsupfrom10%to90%ofitsfinalvaluewhentheincidentopticalpowerischangedabruptly.tristhetransittimeandRCisthetimeconstantoftheequivalentRCcircuit.T

4、hetransittimeisaddedtoRCbecauseittakessometimebeforethecarriersarecollectedaftertheirgenerationthroughabsorptionofphotons.Themaximumcollectedtimeisjustequaltothetimeanelectrontakestotraversetheabsorptionregion.Thereisatrade-offbetweenthebandwidthandtheresponsivity(s

5、peedversussensitivity)ofphotodetector.Often,theRCtimeconstantRClimitsthebandwidthbecauseofelectricalparasitics.Thesehigh-speedphotodetectorsshowflatresponseinbothamplitudeandphaseupto25GHzandareoptimizedforfrequency-domainapplications.Thehigh-sensitivityModel1414nea

6、r-IRphotodetectorsuse25-µm-diameterback-illuminatedInGaAsSchottkyphotodiodeswithpeakresponsivitiesof0.6A/Wat1300nm.Theactivelayeristwiceasthickasinourultrahigh-speedModel101Xmodule,producinga50%greaterresponsivitybetween950nmand1650nm.Theconversiongainwitha50-Wloadis

7、15V/W.25-GHzNear-IRPhotodetectorU2tXPDV2020R-VF-FPphotodetectorUltra-highspeedopticalpulsewaveformmeasurementisAchievedbyusingthesub-picosecondopticalpulsegenerationtechnologywithapassivelymode-lockedfiberlaserandthenonlinearopticaltechnologywiththesum-frequency(SF)l

8、ightgeneration.