Microsoft PowerPoint - Chapter 1.ppt

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祭失汪
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1 3 Moochomatic plae wave E = E cos( ωt kz + φ ) x o o k = E (,) zt = Re[ E exp( jφ )exp j( ωt kz)] o x o o E (,) zt = Re[ E exp j( ωt kz)] x c 4

2 Et (,) = E cos( ωt k + φ ) Wave vecto o o k = k x x + k y y + k z z ω φ = ωt kz + φ = costat o Phase velocity: v dz ω = = = v dt k 5 7 l l l 6 8

3 E E E E + + = εεµ ο ο x y z t (5) A E = cos( ωt k) (6) = 4 π ( w ) o (7) 9 Phase velocity v = ε ε oµ o () (b) Refactive idex c = = v ε () Isotopic (c) Aisotopic (a) 0 ε + N α ε ο

4 3 5 ω δω ω δω δ δω ω 4 6

5 v g = d ω dk () dω v( g vacuum) = = c= phase velocity dk () ω c π = v k = [ ][ ] ( ) (3) 7 9 Dispesive medium dω v g( medium) = = dk v ( medium) = g c N g c d d (4) Goup idex N g = d d (5) 8 0

6 c E = vb = B x y y v v 3 c E = vb = B x y y ε ε E = B o x y µ o () () S = Eegy flow pe uit time pe uit aea ( Av t)( εε o Ex) S = = vεε E = v εεeb A t (istataeous iadiace) o x o x y (3) 4

7 Poytigvecto S = E B v εε o (4) Aveage iadiace (itesity) I = S = v εεe aveage o o I = S = cε E = (.33 0 ) E 3 aveage o o o (5) (6)

8 TIR ad evaescet wave (a) (b) (c) 9 3 o v t AB ' = = si si si v = = v i t i v t si vt vt AB ' = = si si i t () Sell s Law Citical agle si c = () 30 3

9 E cos [ si ] = = E / 0, i i / i0, cos i + [ si i] (a) t E cos t 0, i = = / Ei0, cos i + [ si i] (b) Tasvese electical field (TE) / E 0,// [ si i] cosi // = = / Ei0,// [ si i] + cosi (a) Tasvese magetic field (TM) t E = = cos t 0,// i // / Ei0,// cos i + [ si i] (b) Bouday coditios E B E = E exp j( ωt k ) i io i E = E exp j( ωt k ) o E = E exp j( ωt k ) t to t tagetial tagetial () = E () tagetial () = B () tagetial (?) 34 Nomal icidece // + t// = ad + = t ta p = // = = => liealy polaized wave + (Bewste s agle o polaizatio agle) (3) (4) (5) 36

10 (a) (b) φ φ Applicatios Camea polaizatio filtes (PL) Suglasses Lase tubes (Bewste agle) 38 40

ta p = (Bewste s agle o polaizatio agle) => liealy polaized

11 ta p = (Bewste s agle o polaizatio agle) => liealy polaized wave (5) E = = E cos [ si ] / 0, i i / i0, cos i + [ si i] (a) E / 0,// [ si i] cos i // = = / Ei0,// [ si i] + cosi (a) 4 si i > =.0 exp( jφ ) =.0 exp( jφ ) // // (amplitude of the ef. is equal to that of ic. with phase chage) 43 (a) (b) 4 φ φ 44

12 Phase chage i TIR / [si i ] ta( φ ) = (6) cos [si ] ta( φ ) cos / i // + π = i i (7) >c Evaescet c wave α y Et, ( yzt,,) = e exp j( ωt kizz) (8) Atteuatiocoef. Peetatio depth α π = / [( ) si i ] (9) Iteal eflectio > o phase chage at omal icidece Exteal eflectio < phase shift of 80º at omal icidece fo light both i iteal ad exteal eflectios 46 48

13 Light itesity o iadiace I = v ε ε E o o (0) Reflectace R E E R = = = = E o, o,// ad R // // io, Eio,// () : complex R: eal E = ( E )( E ) * o,// o,// o,// Nomal icidece R = R = R = // + ( ) () e.g. ai-glass 49 5 Tasmittace E E T = = t T = = t E E to, to,// ( ) ad // ( ) // io, io,// Nomal icidece T = T = T = 4 // ( + ) (3) (4) Powe cosevatio R + T = Examples: 50 5

14 課程編號科目名稱光電導論授課教師黃鼎偉課程編號科目名稱光電導論授課教師黃鼎偉 53 課程編號科目名稱光電導論授課教師黃鼎偉 55 課程編號科目名稱光電導論授課教師黃鼎偉 56

16 LC optical esoatos Stoe eegy Filteig light at cetai fequecies (wavelegths) Used i lase, itefeece filte, ad spectoscopic applicatios 6 63 Statioay o stadig EM waves m( ) = L m =,,3... () Cavity mode: υ R ~ R ~ δυ υ υ υ υ (a) (b) (c) 6 R R 64

17 c vm = m( ) = mv f ; v f = c /L L Lowest feq. () I = I ( R) ( R) + 4Rsi ( kl) tasmitted icidet (6) Fee spectal age A+ B = A+ A exp( j kl) Ecavity = A+ B+... E cavity 4 6 = A+ A jkl + A j kl + A jkl + A = exp( ) exp( 4 ) exp( 6 )... exp( j kl) E cavity A = exp( j kl) I cavity = I o ( R) + 4Rsi ( kl) Io I ; max = k ml = mπ ( R) (3) (4) Spectal width (FWHM) Fiesse / δ v f R v = π m ; F F = R (5) Fiesse: the atio of mode sepaatio to spectal width 66 68

18 Lateal shift of the eflected beam due to TIR z = δ ta i δ 69 7 Optical tuelig Fustated total iteal eflectio (FTIR) 70 7

19 Fustated total iteal eflectio Pefect coheece: ay two poits such as P ad Q sepaated by ay time iteval ae alwayscoelated. Beam splitte Gap thickess ad Refactive idex υ ο υ υ υ ο υ (a) (b) υ 73 υ υ 75 Mutual tempoal coheece ove the time iteval (a) Noitefeece A Itefeece t Noitefeece B Souce Time (b) P Q c Spatiallycoheetsouce (c) c Aicoheetbeam Space 74 (a) Two waves ca oly itefee ove the time iteval t. (b) Spatial coheece ivolves compaig the coheece of waves emitted fom diffeet locatios o the souce. 76(c) A icoheet beam.

Huyges-Fesel piciple 77 79 Fauhofe diffactio Fesel diffactio Icidet light beam: a plae wave Obsevatio (detectio): fa away fom the apetue δy δe ( δy)exp( jky si ) () y= a () y= 0 E( ) = C δ yexp(

20 Huyges-Fesel piciple Fauhofe diffactio Fesel diffactio Icidet light beam: a plae wave Obsevatio (detectio): fa away fom the apetue δy δe ( δy)exp( jky si ) () y= a () y= 0 E( ) = C δ yexp( jkysi ) y Scee R =Lage y y a b c z δy ysi z = 0 (a) φ = ky si Lightitesity (b) 78 (a) The apetue is divided ito N umbe of poit souces each occupyig δy with amplitude δy. (b) The itesity distibutio i the eceived light at the scee fa away 80 fom the apetue: the diffactio patte

y= a E( ) = C δ yexp( jky si ) () y= 0 j ka si Ce asi( kasi ) E( ) =

of o diffactio patte coicides with the mi.of the othe. I si =.

21 y= a E( ) = C δ yexp( jky si ) () y= 0 j ka si Ce asi( kasi ) E( ) = kasi ' Casi( ka si ) I( ) = [ ] = I(0)sic ( β); β = ka si (3) ka si m si = ; m =±, ±,... (4) a Rayleigh citeio: two spots ae esolvable whe the picipal max. of o diffactio patte coicides with the mi.of the othe. I si =. D 8 83 Divegece agle of ai disk si =. (5) D d si = m; m = 0, ±, ±,... (7) ' Casi( ka si ) ( ) [ ] (0)sic ( ); si I = = I β β = ka kasi (a) (b) 8 84

22 d(si ± si ) = m; m = 0, ±, ±,... (8) m i 85 γ γ 86

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