講者： 許永昌 老師 1

Contents Models of light: Wave Model Ray Model Photon Model Double-slit interference ( 實驗 7) The diffraction grating Single-Slit diffraction ( 實驗 7) Choosing a model of light Interferometers ( 實驗 10) Michelson interferometer Holography 2

Models of light ( 請預讀 P670~P672) 3

Action Purpose: Get the feeling about the wave and ray nature of light. Objects: A laser pen An aerosol A narrow single slit Action: Spraying an aerosol into the laser beam. Send the laser beam through single slit. Light travels in a straight line? Light is a wave? Edge effect? 4

Double-slit interference ( 請預讀 P672~P678) 5

Double-Slit Interference (continue) Model: ( 做很多假設喔 )  r  dsin  ~d . On screen: y=Ltan  ~L . On the screen: D net =D 1 +D 2. D 1 =asin(kr 1  t+  0 )=asin(  1 ) Bright fringe (Constructive): D 1 =D 2. k  r=2  m.   r=m. We get y bright =m L/d. Fringe spacing= L/d. 6 r1r1 r2r2 L d 

Double-slit interference (continue) Intensity: I= ½ c  |E 0 | 2. 此處 a=E 0. E 0 為 的振幅，如果它是由 n 個波疊加的話。 Bright fringe: A(y bright )=2a. I max =4I 0. Dark fringe: A(y dark )=0. I min =0. Average: 2I 0. 7

Mathematics 8 1t1t a D1D1 x y 此處的 x,y 是對 phasor diagram 在講，而不是 對描述光干涉空間在講，請小心。 a D1D1 x y 1t1t 2t2t a D2D2 A

Double-slit interference (final) From this figure, we can find that A=2acos(  /2). Substitute Eqs. shown in P6 into this equation, we get Intensity: 9 

Homework Student Workbook: 1, 2, 4 10

Exercise How about triple-slit interference? Please use the phasor diagram to find the positions of dark fringes. Hint:  =? How about the positions of bright fringes? 11 dd

The diffraction grating ( 請預讀 P678~P680) 12

The diffraction grating (continue)  =dsin . Constructive:  =2  m. y bright =m L/d ( 由圖上可見，其實  bright 並不小，因此，這近似 有點不切實際。因此，課本只寫到 dsin  bright =m.) A=Na. I max =N 2 I 0. Destructive: N  =2  m & m  m’N. A=0. I min =0. Code: grating.mgrating.m 13 L/dL/d I0N2I0N2

Mathematics 14 Re(e i  ) Im(e i  ) 數學上的進化 : sin(kx  t+  0 )  sin(  )  y component of vector (phasor graph)  complex variable. 數學上的進化 : sin(kx  t+  0 )  sin(  )  y component of vector (phasor graph)  complex variable.

Homework Student Workbook 5, 7 15

Single-Slit diffraction ( 請預讀 P681~P684) 16

Mathematics where  =k  r=k  b/N sin , a= E 0 /N. Intensity: Angles of dark fringe: bsin  =m, m  0,  [  ]

The Ray and Wave models of light ( 請 預讀 P685~P687) 18

Homework Student Workbook 8, 9, 10, 11 19

Interferometers ( 請預讀 P687~P690) 20

Holography ( 請預讀 P690~P691) Holography is an important application of Wave Optics. 21

Homework Student Workbook 13, 14 Student Textbook 49 請製作 terms and notation 的卡片 22