第十章 光学性质(彩色版).pdf

光的传播
材料导论 E λ
第十一章 Position
光学性质 H
光波谱系
1
可见光 c =
ε 0µ0
X-radiation Microwaves 微波
12 µ =4π×10-7H/m
无线电波ε0=×10 F/m 0
γ-radiation UV IR Radio waves
c = λν
10-6 10-3 1 103 106 109 1012
Wavelength(nm)
光与材料的相互作用
hc Absorption I 吸收
E = hν= 反射 A
λ Reflected beam
IR Transmitted beam 透射
IT
h is Planck's constant
θi
θr
θi
−34 Refraction 折射
h = ×10 J ⋅s I0
Incident beam
入射
1
作用机理
I0 = IT + I A + I R
能量吸收
电子极化
T + A + R =1 速度降低折射
I I I 电子跃迁
T = T , A = A , R = R
I0 I0 I0
金属中的电子跃迁
E5
E4
Electron
E3
Excitation, Empty states
Energy
∆E = E4-E2 = hν42 ∆E ∆E
E
2 Fermi
energy
Energy
E1
频率为ν的入射光子
42 电子跃迁 Photon
absorbed Photon
Filled states
emitted
非金属中的电子跃迁
Impurity
Excited
level band
(free)
electron Conduction
band
Conduction Conduction
∆E
∆E ∆E gap
Energy
Band Band
E gap
Energy g
Band Band Hole
Photon
Photon
emitted band
Valence Valence
absorbed band
Valence Valence Photon
absorbed
2
折射
Transmitted beam 透射
∆E Photon ∆E Phonon
1 1 I
emitted Generated T
having
∆E1 energy ∆E
ν= 1 θr
1 h
∆E ∆E
2 2 θi
折光指数
I
0 c sinθ
Photon Photon Incident beam n = = i
emitted emitted
入射 v sinθr
∆E ∆E
ν= 2 ν= 2
2 h 2 h
例题:,如何能使
1 光线泄漏为最小?
v =
εµ
β
c εµ β= 90°
n = = =