1-Nature of light-2optics.hanyang.ac.kr/~shsong/1-Nature of light-rev.pdf · 2016. 8. 31. · 11....
Transcript of 1-Nature of light-2optics.hanyang.ac.kr/~shsong/1-Nature of light-rev.pdf · 2016. 8. 31. · 11....
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Physical Physical OpticsOpticsProfessor 송 석호, Physics Department (Room #36-401)
2220-0923, 010-4546-1923, [email protected]
Office Hours Mondays 10:00-12:00, Wednesdays 10:00-12:00
Grades Midterm Exam 30%, Final Exam 30%, Homework 20%, Attend 10%
Textbook Introduction to Optics (F. Pedrotti, Wiley, New York, 1986)
Homepage http://optics.hanyang.ac.kr/~shsong
Reference web: Lecture note of Prof. Robert P. Lucht, Purdue University
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OpticsOptics
www.optics.rochester.edu/classes/opt100/opt100page.html
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Light is a Ray (Geometrical Optics)
1. Nature of light2. Production and measurement of light3. Geometrical optics4. Matrix methods in paraxial optics5. Aberration theory6. Optical instrumentation27. optical properties of materials
Light is a Wave (Physical Optics)
8. Wave equations9. Superposition of waves10. Interference of light11. Optical interferometry12. Coherence13. Holography14. Matrix treatment of polarization15. Production of polarized light
Course outlineCourse outline
Light is a Wave (Physical Optics)
25. Fourier optics16. Fraunhofer diffraction17. The diffraction grating18. Fresnel diffraction19. Theory of multilayer films20. Fresnel equations* Evanescent waves
26. Nonlinear optics
Light is a Photon (Quantum Optics)
21. Laser basics22. Characteristics of laser beams23. Laser applications24. Fiber optics
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Also, see Figure 2-1, Pedrotti
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(Genesis 1-3) And God said, "Let there be light," and there was light.
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A Bit of HistoryA Bit of History
1900180017001600 200010000-1000
“...and the foot of it of brass, of the lookingglasses of the women
assembling,” (Exodus 38:8)
Rectilinear Propagation(Euclid)
Shortest Path (Almost Right!)(Hero of Alexandria)
Plane of IncidenceCurved Mirrors(Al Hazen)
Empirical Law of Refraction (Snell)
Light as PressureWave (Descartes)
Law of LeastTime (Fermat)
v
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More Recent HistoryMore Recent History
2000199019801970196019501940193019201910
Laser(Maiman)
Quantum Mechanics
Optical Fiber(Lamm)
SM Fiber(Hicks)
HeNe(Javan)
Polaroid Sheets (Land)Phase Contrast (Zernicke)
Holography (Gabor)
Optical Maser(Schalow, Townes)
GaAs(4 Groups)
CO2(Patel)
FEL(Madey)
Hubble Telescope
Speed/Light (Michaelson)
Spont. Emission (Einstein)
Many New Lasers
Erbium Fiber Amp
Commercial Fiber Link (Chicago)
(Chuck DiMarzio, Northeastern University)
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LasersLasers
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Nature of LightNature of Light
ParticleParticle
Isaac Newton (1642Isaac Newton (1642--1727)1727)
OpticsOptics
WaveWave
Huygens (1629Huygens (1629--1695)1695)
Treatise on Light (1678)Treatise on Light (1678)
WaveWave--Particle DualityParticle Duality
De De BroglieBroglie (1924)(1924)
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Maxwell -- Electromagnetic waves
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PlanckPlanck’’s hypothesis (1900)s hypothesis (1900)
Light as particlesLight as particlesBlackbody Blackbody –– absorbs all wavelengths and conversely emits absorbs all wavelengths and conversely emits all wavelengthsall wavelengthsLight emitted/absorbed in discrete units of energy (quanta),Light emitted/absorbed in discrete units of energy (quanta),
E = n h fE = n h fThus the light emitted by the blackbody is,Thus the light emitted by the blackbody is,
⎟⎟⎠
⎞⎜⎜⎝
⎛
−=
1
12)( 52
kThc
e
hcMλλ
πλ
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Photoelectric Effect (1905)Photoelectric Effect (1905)
Light as particlesLight as particlesEinsteinEinstein’’s (1879s (1879--1955) explanation1955) explanation
light as particles = photonslight as particles = photons
Kinetic energy = hƒ - Ф
Electrons
Light of frequency ƒ
Material with work function Ф
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WaveWave--particle duality (1924)particle duality (1924)
All phenomena can be explained using either All phenomena can be explained using either the wave or particle picturethe wave or particle picture
Usually, one or the other is most convenientUsually, one or the other is most convenient
In In OPTICSOPTICS we will use the wave picture we will use the wave picture predominantlypredominantly
ph
=λ
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Nature of LightNature of Light
Particle : Isaac Newton (1642Particle : Isaac Newton (1642--1727)1727)
Wave : Christian Huygens (1629Wave : Christian Huygens (1629--1695)1695)
WaveWave--Particle Duality : Luis De Particle Duality : Luis De BroglieBroglie (1924)(1924)
All phenomena can be explained using All phenomena can be explained using either the wave or particle pictureeither the wave or particle pictureUsually, one or the other is most convenientUsually, one or the other is most convenientIn In OPTICSOPTICS we will use the wave picture we will use the wave picture predominantlypredominantly
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LetLet’’s warms warm--upup
일반물리일반물리
전자기학전자기학
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Question Question
How does the light propagate through a glass medium?
(1) through the voids inside the material.(2) through the elastic collision with matter, like as for a sound.(3) through the secondary waves generated inside the medium.
Construct the wave front tangent to the wavelets
Secondaryon-going wave
Primary incident wave
What about –r direction?
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Electromagnetic WavesElectromagnetic Waves
0εQAdE =⋅∫
0=⋅∫ AdB
dtdsdE BΦ−=⋅∫
dtdisdB EΦμε+μ=⋅∫ 000
Gauss’s Law
No magnetic monopole
Faraday’s Law (Induction)
Ampere-Maxwell’s Law
Maxwell’s Equation
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Maxwell’s Equation
Gauss’s Law
No magnetic monopole
Faraday’s Law (Induction)
Ampere-Maxwell’s Law
∫∫∫ ερ
=⋅∇=⋅ dvdvEAdE0
0=⋅∇=⋅ ∫∫ dvBAdB
∫∫∫ ⋅−=⋅×∇=⋅ AdBdtdAdEsdE
∫∫
∫∫
⋅εμ+⋅μ=
Φεμ+μ=⋅×∇=⋅
AdEdtdAdj
dtdiAdBsdB E
000
000
tEjB∂∂
εμ+μ=×∇ 000
djtE=
∂∂
ε0 ( )djjB +μ=×∇ 0
0ερ
=⋅∇ E⇒
0=⋅∇ B⇒
tBE∂∂
−=×∇⇒
⇒
⇒
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Wave equationsWave equations
tBE∂∂
−=×∇tEB∂∂
=×∇ 00εμ
( ) ⎟⎟⎠
⎞⎜⎜⎝
⎛∂∂
−∂∂
=×∇∂∂
=×∇×∇tB
tE
tB 0000 εμεμ
( ) BB 2−∇=×∇×∇ kzjyix ˆˆˆ ∂∂
+∂∂
+∂∂
=∇
( ) ( ) BBBB 22 −∇=∇−⋅∇∇=×∇×∇( ) ( ) ( )CBABCACBA ⋅−⋅=××
2
2
002
tBB
∂∂
=∇ εμ
2
2
002
tEE
∂∂
=∇ εμ
022
002
2
=∂∂
−∂∂
tB
xB εμ
022
002
2
=∂∂
−∂∂
tE
xE εμ
Wave equations
In vacuum
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Scalar wave equationScalar wave equation
2 2
0 02 2 0x tμ ε∂ Ψ ∂ Ψ− =
∂ ∂
0 cos( )kx tωΨ = Ψ −
02002 =ωεμ−k cvk
≡==00
1εμ
ωSpeed of Light
smmc /103sec/1099792.2 88 ×≈×=
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Transverse ElectroTransverse Electro--Magnetic (TEM) wavesMagnetic (TEM) waves
BEtEB ⊥⇒∂∂
εμ−=×∇ 00
Electromagnetic Wave
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Energy carried by Electromagnetic WavesEnergy carried by Electromagnetic Waves
Poynting Vector : Intensity of an electromagnetic wave
BES ×=0
1μ
2
0
2
0
0
1
1
BcEc
EBS
μ=
μ=
μ=
(Watt/m2)
⎟⎠⎞
⎜⎝⎛ = c
EB
202
1 EuE ε=Energy density associated with an Electric field :
2
021 BuB μ
=Energy density associated with a Magnetic field :
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n1n2
Reflection and Refraction
11 θ′=θReflected ray
Refracted ray 2211 sinsin θθ nn =
Smooth surface Rough surface
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Reflection and Refraction
00εμμε
==vcnIn Media,
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Interference & Diffraction
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Reflection and Interference in Thin Films Reflection and Interference in Thin Films
• 180 º Phase changeof the reflected light by a media with a larger n
• No Phase changeof the reflected light by a media with a smaller n
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Interference in Thin Films
tn1
Phase change: π
n2 Phase change: π
n2 > n1
λ=λ==δ1
12
nmmt n
Bright ( m = 1, 2, 3, ···)
( ) ( )λ+=λ+==δ1
21
21
12
nmmt n
Bright ( m = 0, 1, 2, 3, ···)
tnPhase change: π
No Phase change
( ) ( )λ+=λ+==δn
mmt n 21
212
λ=λ==δnmmt n2
Bright ( m = 0, 1, 2, 3, ···)
Dark ( m = 1, 2, 3, ···)
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InterferenceYoung’s Double-Slit Experiment
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Interference
The path difference
λ=θ=δ msind( )λ+=θ=δ 21msind
⇒ Bright fringes m = 0, 1, 2, ····
⇒ Dark fringes m = 0, 1, 2, ····
The phase differenceλ
θπ=π⋅
λδ
=φsind22
θ=−=δ sindrr 12
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Hecht, Optics, Chapter 10
Diffraction
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Diffraction
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Diffraction GratingGrating
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Diffraction of XDiffraction of X--rays by Crystals rays by Crystals
d
θθ
θ
dsinθ
Incidentbeam
Reflectedbeam
λθ md =sin2 : Bragg’s Law
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Regimes of Optical DiffractionRegimes of Optical Diffraction
d > λ
Far-fieldFraunhofer
Near-fieldFresnel
Evanescent-fieldVector diff.