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Chapter 07&08 & 09 & 10. PHOTONIC-CRYSTAL OPTICS. 下几页列出重 要的概 念,需掌握. WaVE Transfer Matrix. Scattering Matrix. Airy's formulas. Fabry -Perot Etalon. Bragg Grating. Bloch Modes. Chapter 8. Comments…why?. Comments…integration circuits. 在小空间里控制光场的传播 , 用 于信息交换及应用!. - PowerPoint PPT Presentation
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Chapter 07&08 & 09 & 10
PHOTONIC-CRYSTAL OPTICS
下几页列出重要的概念,需掌握
WaVE Transfer Matrix
Scattering Matrix
Airy's formulas
Fabry-Perot Etalon
Bragg Grating
Bloch Modes
Chapter 8
Comments…why?...
Comments…integration circuits
在小空间里控制光场的传播,用于信息交换及应用!
Photonic Crystals Metamaterials
From a similar consideration尺寸更小,亚波长, <200nm
PLANAR-MIRROR WAVEGUIDES
Firstly, from ray optics…
Reflection by mirrors Correct in microwave frequency
Why?... At microwave Perfect electric conductor
(PEC) = ―ε n= j
|r|=1 Phase change: 0 or π (半波损)
0: 边界场强极大 : π 边界场强为零
Periodicity Discrete modes
Propagation Constants
Dispersion Relation
截止频率 f0 。 f < f0 ( 波长大时 ) 模式消失,无法传播。在截止频率处,群速度为零,即慢光效应。
/c c d
Group Velocity
c
c.cosθ
一种特殊的光学延迟线 θπ/2, 越慢
Field Distributi
ons正交归一本征模式
Multimode Fields
Comments m=1,2,3…
How about m=0? Infinite field amplitude, not allowed
Cutoff size: d>dc=/2 /c c d
But coaxial PEC waveguide supports m=0 TEM mode, which in non-cutoff!
PLANAR DIELECTRIC WAVEGUIDES
Comparing to Section 1No longer PEC boundary conditions
With field outside the core With non-zero/pi reflection phase
Now Electromagnetic optics
Phase condition
Field Distributions
… with EM boundary conditions!
Dispersion Relation
Dispersion…
Group Velocity Goos-Hänchen shift
当相位为常数时 , v=c.cosθ
Goos-Hänchen shift
Usually… positive and very small, <0.05λ
Could be negative and with large value in left-handed metamaterials
Backward energy flux Strong dispersion in
LHM
GH shift can make a cavity
nature_450_397
TWO-DIMENSIONAL WAVEGUIDES
Boundary Conditions
Applications
OPTICAL COUPLING IN WAVEGUIDES
Input Couplers
尽可能大的交叠积分
End-Fire configuration
Prism & Grating Side Couplers
To match the wavevector m …
FIBERS圆柱对称二维光波导,选择性阅读
Vortex modes & Higher-OAM modes
Resonator From waveguide Spatial confinement of EM waves
select specific frequencies from a signal To generate stronger EM field intensity For applications that need strong EM field
Laser Quantum Physics ……
e of d r
Examples
PLANAR-MIRROR RESONATORS
Resonator Modes
Interference … standing wave …
Similar to 1D waveguides …
Smaller d larger vf (uncertainty principle)
As Traveling waves
Multiple interference…
Traveling-Wave Resonator
驻波的缺点:场强分布不均匀,例如 E~cos(kz) 。Traveling wave? 场强均匀分布,优点 : 例如可以充分利用增益介质等。
Fabry-Perot resonator
Method I
Methods II
E1 : E0 透射 +E3 反射; E3 : E1 反射; E2 : E1 透射; E4 : E3 透射
E0 E1 E2
E3E4 Much simple
Transfer Matrix Method
exp(―jkd)
不要忘了相位项exp(―jkd) !
r 不能为 1
Resonance strong dispersion smaller group velocity
多次反射减缓光的速度
Quality Factor Q
Q 越大,共振越强,群速度越小:空间上对光脉冲的挤压,增强能量密度
Off-Axis Resonator Modes
A special design for optical delay purpose … because a longer optical path…
SPHERICAL-MIRROR RESONATORS
Ray Confinement
Resonator stability diagram
Two-Dimensional Rectangular Resonators
Circular Resonators and Whispering-Gallery Modes
Three-Dimensional Rectangular Cavity Resonators
MICRORESONATORS Microresonators are resonators in which one or
more of the spatial dimensions assumes the size of a few wavelengths of light or smaller.
Applications
To confine other elementary excitations Electrons, Polaritons, ions…
To enhance the interaction of photons with excitations
To enhance the quantum phenomena of excitations Especially when the size is comparable with the
wavelength Optical Integration circuits
201210 月19 日
Science
Comment Size of resonator
Usually a minimum of λ/2
Smaller size d? From 2dk=2mπ, k=n2π/ λ, one can use a
medium with larger n value To λ/2n
Other possibility? Metamaterial with negative nL
nLdL+nRdR=mλ/2 Solution of m=0 is possible
dL=―nRdR/nL
两个厚度成正比关系,可以缩放 腔的厚度可以做的尽可能的小
END
Homework 07 EXERCISE 7.1-1
解释什么是 Omnidirectional Reflection 。我 们 日 常 生 活 中 用 的 镜 子 是 不 是Omnidirectional Reflection ? 为什么?
Homework 08 解释方程 8.2-25 每一项的物理意义。 Problems 8.2-6
Homework 10 EXERCISE 10.1-1
Problem 10.1-7