Physical Optics
Professor
송 석호, Physics Department (Room #36-401)
2220-0923, 010-4546-1923, shsong@hanyang.ac.kr
Office Hours
Mondays 10:00-12:00, Wednesdays 10:00-12:00
Grades
10%
Midterm Exam 30%, Final Exam 30%, Homework 20%, Attend
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
Optics
www.optics.rochester.edu/classes/opt100/opt100page.html
Course outline
Light is a Ray (Geometrical Optics)
1. Nature of light
2. Production and measurement of light
3. Geometrical optics
4. Matrix methods in paraxial optics
5. Aberration theory
6. Optical instrumentation
27. optical properties of materials
Light is a Wave (Physical Optics)
25. Fourier optics
16. Fraunhofer diffraction
17. The diffraction grating
18. Fresnel diffraction
19. Theory of multilayer films
20. Fresnel equations
* Evanescent waves
26. Nonlinear optics
Light is a Wave (Physical Optics)
Light is a Photon (Quantum Optics)
8. Wave equations
9. Superposition of waves
10. Interference of light
11. Optical interferometry
12. Coherence
13. Holography
14. Matrix treatment of polarization
15. Production of polarized light
21. Laser basics
22. Characteristics of laser beams
23. Laser applications
24. Fiber optics
Also, see Figure 2-1, Pedrotti
(Genesis 1-3) And God said, "Let there be light," and there was light.
A Bit of History
“...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 Incidence
Curved Mirrors
(Al Hazen)
-1000
0
Wave Theory (Longitudinal)
(Fresnel)
Empirical Law of
Refraction (Snell)
Light as Pressure
Wave (Descartes)
Transverse Wave, Polarization
Interference (Young)
Law of Least
Time (Fermat)
Light & Magnetism (Faraday)
v<c, & Two Kinds of
Light (Huygens)
Corpuscles, Ether
(Newton)
1000
1600
1700
EM Theory (Maxwell)
Rejection of Ether,
Early QM (Poincare,
Einstein)
1800
1900
2000
(Chuck DiMarzio, Northeastern University)
More Recent History
Laser
(Maiman)
Polaroid Sheets (Land)
Optical Fiber
(Lamm)
Speed/Light
(Michaelson)
HeNe
(Javan)
GaAs
(4 Groups)
CO2
(Patel)
Holography
(Gabor)
Spont. Emission
(Einstein)
1920
SM Fiber
(Hicks)
Optical Maser
(Schalow, Townes)
Quantum Mechanics
1910
Phase
Contrast
(Zernicke)
Hubble
Telescope
Erbium
Fiber Amp
FEL
(Madey)
Commercial
Fiber Link
(Chicago)
Many New
Lasers
1930
1940
1950
1960
1970
1980
1990
2000
(Chuck DiMarzio, Northeastern University)
Lasers
Nature of Light
„
„
„
Particle
„
Isaac Newton (1642-1727)
„
Optics
Wave
„
Huygens (1629-1695)
„
Treatise on Light (1678)
Wave-Particle Duality
„
De Broglie (1924)
Maxwell -- Electromagnetic waves
Planck’s hypothesis (1900)
„
„
„
„
Light as particles
Blackbody – absorbs all wavelengths and conversely emits
all wavelengths
Light emitted/absorbed in discrete units of energy (quanta),
E=nhf
Thus the light emitted by the blackbody is,
⎞
2πhc ⎛
1
⎟
⎜
M (λ ) =
hc
5
⎜
λ ⎝ e λkT − 1 ⎟⎠
2
Photoelectric Effect (1905)
„
„
Light as particles
Einstein’s (1879-1955) explanation
„
light as particles = photons
Light of frequency ƒ
Kinetic energy = hƒ - Ф
Electrons
Material with work function Ф
Wave-particle duality (1924)
„
All phenomena can be explained using either
the wave or particle picture
h
λ=
p
„
Usually, one or the other is most convenient
„
In OPTICS we will use the wave picture
predominantly
Nature of Light
„
Particle : Isaac Newton (1642-1727)
„
Wave : Christian Huygens (1629-1695)
„
Wave-Particle Duality : Luis De Broglie (1924)
„
„
„
All phenomena can be explained using
either the wave or particle picture
Usually, one or the other is most convenient
In OPTICS we will use the wave picture
predominantly
Let’s warm-up
일반물리
전자기학
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.
Secondary
on-going wave
Primary incident wave
Construct the wave front
tangent to the wavelets
What about –r direction?
Electromagnetic Waves
Maxwell’s Equation
G G Q
∫ E ⋅ dA =
Gauss’s Law
G G
∫ B ⋅ dA = 0
No magnetic monopole
ε0
G G
dΦ B
⋅
=
−
E
d
s
Faraday’s Law (Induction)
∫
dt
G G
dΦ E Ampere-Maxwell’s Law
⋅
=
μ
+
ε
μ
B
d
s
i
∫
0
0 0
dt
Maxwell’s Equation
G G ρ
G G
G G
ρ
Gauss’s Law
∇⋅E =
E
⋅
d
A
=
∇
⋅
E
dv
=
dv
⇒
∫
∫
∫ε
ε0
0
G G
G G
G G
No magnetic monopole
⇒
∇⋅B = 0
∫ B ⋅ dA = ∫ ∇ ⋅ Bdv = 0
G
G G
G G G
d G G
G
G
∫ E ⋅ ds = ∫ ∇ × E ⋅ dA = − dt ∫ B ⋅ dA ⇒ ∇ × E = − ∂B
Faraday’s Law (Induction)
∂t
G G
G G G
dΦ E
B
⋅
d
s
=
∇
×
B
⋅
d
A
=
μ
i
+
μ
ε
∫
∫
0
0 0
dt
G
G
G
G G
G
G
G
d
∂E
= μ 0 ∫ j ⋅ dA + μ 0 ε 0 ∫ E ⋅ dA ⇒ ∇ × B = μ 0 j + μ 0 ε 0
dt
∂t
G
G G
G G
∂E G
⇒
ε0
= jd
∇ × B = μ 0 ( j + jd ) Ampere-Maxwell’s Law
∂t
Wave equations
G
G G
∂B
∇× E = −
∂t
G
G G
∂E
∇ × B = μ 0ε 0
∂t
In vacuum
G
G G G
G
G
∂
∂ ⎛ ∂B ⎞
⎟
∇ × ∇ × B = μ 0ε 0 ∇ × E = μ 0ε 0 ⎜⎜ −
∂t
∂t ⎝ ∂t ⎟⎠
G G G
G
2
∇ × ∇ × B = −∇ B
(
(
)
)
G
2
G
∂ B
∇ 2 B = μ 0ε 0 2
∂t G
G
∂2E
2
∇ E = μ 0ε 0 2
∂t
G
∂ ˆ ∂ ˆ ∂ ˆ
∇=
i+
j+
k
∂x
∂y
∂z
G
G G
G G G
G
G
2
2
∇ × ∇ × B = ∇ ∇ ⋅ B − ∇ B = −∇ B
G G G
G G G
G G G
A× B × C = A⋅C B − A⋅ B C
(
(
) ( )
) ( ) (
∂2B
∂2B
− μ 0ε 0 2 = 0
2
∂x
∂t
Wave equations
2
2
∂ E
∂ E
−
μ
ε
=0
0 0
2
2
∂x
∂t
)
Scalar wave equation
∂ 2Ψ
∂ 2Ψ
− μ 0ε 0 2 = 0
2
∂x
∂t
Ψ = Ψ 0 cos( kx − ω t )
k − μ0ε0ω = 0
2
2
ω
k
=
1
μ 0ε 0
=v≡c
Speed of Light
c = 2.99792 ×108 m / sec ≈ 3 ×108 m / s
Transverse Electro-Magnetic (TEM) waves
G
G G
∂E
∇ × B = −μ 0 ε 0
∂t
⇒
G G
E⊥B
Electromagnetic
Wave
Energy carried by Electromagnetic Waves
Poynting Vector : Intensity of an electromagnetic wave
G 1 G G
S=
E×B
(Watt/m2)
μ0
1
⎞
⎛B
⎜ = c⎟
S=
EB
⎝E
⎠
μ0
1 2 c 2
=
E =
B
cμ 0
μ0
Energy density associated with an Electric field : u E =
1
ε0 E 2
2
Energy density associated with a Magnetic field : u B =
1 2
B
2μ 0
Reflection and Refraction
Smooth surface
Rough surface
Reflected ray
n1
n2
Refracted ray
θ1 = θ1′
n1 sin θ1 = n2 sin θ 2
Reflection and Refraction
In Media,
c
n= =
v
με
μ 0ε 0
Interference & Diffraction
Reflection and Interference in Thin Films
• 180 º Phase change
of the reflected light
by a media
with a larger n
• No Phase change
of the reflected light
by a media
with a smaller n
Interference in Thin Films
δ = 2t = (m +
1
2
(
m + 12 )
)λ n =
λ
n
Bright ( m = 0, 1, 2, 3, ···)
Phase change: π
n
t
No Phase change
δ = 2t = mλ n =
m
λ
n
Dark ( m = 1, 2, 3, ···)
δ = 2t = mλ n1 =
Phase change: π
n1
n2
m
λ
n1
Bright ( m = 1, 2, 3, ···)
t
Phase change: π
n2 > n1
δ = 2t = (m + 12 )λ n1
(
m + 12 )
=
λ
n1
Bright ( m = 0, 1, 2, 3, ···)
Interference
Young’s Double-Slit Experiment
Interference
The path difference
δ = d sin θ = mλ
δ = r2 − r1 = d sin θ
⇒ Bright fringes
δ = d sin θ = (m + 12 )λ ⇒ Dark fringes
The phase difference φ = δ ⋅ 2π = 2πd sin θ
λ
λ
m = 0, 1, 2, ····
m = 0, 1, 2, ····
Diffraction
Hecht,
Optics,
Chapter 10
Diffraction
Diffraction Grating
Diffraction of X-rays by Crystals
Reflected
beam
Incident
beam
θ
θ
θ
d
dsinθ
2d sin θ = mλ
: Bragg’s Law
Regimes of Optical Diffraction
d >> λ
Far-field
Fraunhofer
d~λ
Near-field
Fresnel
d << λ
Evanescent-field
Vector diff.