光的偏振和晶体光学基础课件

EBk第六章光的偏振和晶体光学基础6.3.2椭圆偏振光的产生和波片Wave

platePolarizerPolarizer2．波片

(1)波片的概念基本功能是：在已知的两个正交本征偏振方向上，对入射的偏振光引入特定的附加位相差。

ddThicknessofwaveplatesWhenawaveplatehaslessthan2prelativephasedelay,wesayit’sazero-orderwaveplate.Unfortunately,theytendtobeverythin.Solvefordtofindthethicknessofazero-orderquarter-waveplate:Usinggreenlightat500nmandquartz,whoserefractiveindicesarene–no=1.5534–1.5443=0.0091,wefind:Thisissothinthatitisveryfragileandverydifficulttomanufacture.dd=13.7mm波片的色差d(2)几种常用的单块式波片

d(3)附加位相差可调节的波片－补偿器(a)巴比内补偿器(b)索列尔补偿器TheBabinetCompensatorrotatespolarizationbyanarbitraryamount.Topwedgeiscutwithfastandslowaxesoppositetothoseofbottomwedge.Slideonewedgewithrespecttotheother,changingd1and/or

d2.Inpractice,thetwowedgesarecontacted.TopwedgeBottomwedgeInputbeamd2OpticaxesxyzOutputbeamd1d1TheBabinetCompensatorrotatespolarizationbyanarbitraryamount.

Topwedgeiscutwith"fast"and"slow"axescutoppositetothoseofbottomwedge.Slideonewedgewithrespecttotheother,changingd1and/ord2.[Notethatthismotiondoesn'tdisplacethebeam!]InputbeamTopwedgeBottomwedgeλ/4波片将线偏光转变成圆偏振光

圆起偏器两种圆起偏器光路（a)右旋圆起偏器（b)左旋圆起偏器CircularpolarizersAcircularpolarizermakescircularlypolarizedlightbyfirstlinearlypolarizingitandthenrotatingittocircular.ThisinvolvesalinearpolarizerfollowedbyaquarterwaveplateUnpolarizedinputlightCircularlypolarizedlightQWP45°Polarizer45°polarizedlightQuarterwaveplate(QWP)±45°PolarizerAdditionalQWPandlinearpolarizercompriseacircular"analyzer."45°PolarizerQWP-45°polarizedlight

λ/4片把椭圆偏振光转变成线偏光

λ/4片把椭圆偏振光转变成线偏光λ/4波片将圆偏振光转变成线偏光

圆检偏器

两种圆检偏器光路（a)右旋圆检偏器（b)左旋圆检偏器重要结论

②λ/2波片的Jones矩阵及应用

(a)改变线偏光振动方向

Half-waveplateIftheincidentpolarizationis+45°totheprincipalaxes,thentheoutputpolarizationisrotatedby90°to-45°.Whenabeampropagatesthroughahalf-waveplate,onepolarization

experienceshalfofawavelengthmorephasedelaythantheother.(b)改变椭圆(包括圆）偏振光旋向(3)多个波片级联时的琼斯矩阵4.理想线偏振器对入射光作用的琼斯矩阵任何偏振态光波通过线偏器，

出射光都是线偏光线偏器作用于自然光入射的情形

线偏器琼斯矩阵也可应用于由多个波片和线偏器组成的级联系统

思考题1.有人说:可以用一块四分之一波片将自然光变为椭圆偏振光或圆偏振光。此话对吗？为什么？2.能否用一块绿光的四分之一波片将红光变为圆