光学工程导论讲义(2)

《光学工程导论讲义(2)》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、Lecture2Lecture2ReflectionandRefraction,Snell’sLaw[Readingassignment:Hecht4.3,4.4,4.7]Animportantelementofopticsistheinterfacebetween2materialswithdifferentindexofrefractionreflectedray11n1n2refractedray2nsin=nsin1122sin1n2ifn2n121-------------=-----sin2n1ifnn122

2、1TotalReflectionIfnn,thenwecanhave121=902n2sin=-----cn1–12=90c=sinn2n1Therefractedraydisappears!Thelightistotallyreflected.Thisusuallyoccursinsideaprism,andiscalledtotalinternalreflection.=“criticalangle”.Foratypicalglasswithn=1.5,thecriticalanglecis:–11sin-------=

3、41.8.1.51©JeffreyBokor,2000,allrightsreservedLecture2Sofor=45,thelightisreflected.Averycommonprismistherightangleprism459045LightImpingingataSurfaceTheplanecontainingthelightraypropagationvectorandthesurfacenormaliscalledthe“planeofinci-dence”EE1pnormalE1p1sE1sn111nE

4、E22p2s2p-polarizations-polarization(paralleltoplaneofincidence)•Forageneralpolarizationstateincidentonasurface,wechoosesandpdirectionstodecomposethepolarizationeffects.FresnelReflectionCoefficients[Optionalreading:Hecht4.6]Themagnitudeofreflectionandtransmissionataninterfacebet

5、weennandnaregivenby12222tan–ncos4sincos212221R=---------------------------------T=--------------------------------------------------------------------------------------p2pncos22tan+11sin+cos–211212222sin–ncos4sincos212221R=-----------------------------

6、---T=--------------------------------------------------------s2sncos2sin+11sin+21122©JeffreyBokor,2000,allrightsreservedLecture2n–n221near==0RR=-----------------.Forn=1.5R4%Noticealso,if1spn+n21+=---,thentan,andR0.212pn2canbeshowntobegivenbytan=-----.Th

7、isangleisknownas“Brewster’sangle”or11n1the“Polarizingangle”.PolarizationReadingAssignment:Hecht8.1,8.2]•Lightwaveshavetransversepolarization•Theelectricfieldvectorpointsinadirectionperpendiculartothepropagationdirection(raydirection).•Themagneticfieldvectorisorthogonaltopropagat

8、iondirection.Generally,wecanignorethemag-neticf