Introduction to OpticsPhysics 313/313H
Matt DeCamp
DeCamp Research
S. Takada, Proteins (2001)
Use 40 femtosecond (10-15sec) laser
pulses to study motion of complex
molecules
Laser system in Sharp 012
I am an Atomic, Molecular, and
OPTICAL (AMO) physicist.
DeCamp Research Cont
Tightly focus light to generate x-rays
Course Plan• Introduction to light
– Waves– E-M Theory
• Light/matter interactions
• Optical Devices– Telescopes– Prisms
• Interference effects– Holograms– Gratings– Fourier Series
• Polarization – LCDs
• Optical Cavities– Lasers
What is Optics?
• Wikipedia: Optics is a branch of physics that describes the behavior and properties of light and the interaction of light with matter.
– What is “light”?
– How does light “behave”?
– How does matter effect light’s properties?
The study of light properties
through the centuries
• “Burning Glasses” in ancient Greek times
• Plato mentions light “bending”
• Alhazen (1000AD) studies mirrors
History Continued:
Wave vs. Particle
• Galileo (1609) builds telescope
to search the heavens
• Hooke (1665) proposes wave
nature of light
• Newton (1704) disperses light,
particle nature dominant
• Young (1803) and Fresnel
(1817) prove wave nature
through interference
History: Light Speed
• Romer (1676) used
planetary motion to measure
speed of light ~2.4x108 m/s
• Fizeau (1849) used a shutter
to measure the speed of
light 3.15x108m/s
• Speed of light is DEFINED
2.99792458x108m/s
History Cont.:
Electromagnetic Theory• Faraday (1845) use magnetic fields to alter light properties
• Maxwell (1873) unifies Electromagnetic fields
A
0 0
A
A
A
BE dl dS
t
EB dl dS
t
B dS 0
E dS 0
µ ε
∂= −∫ ∫∫
∂
∂=∫ ∫∫
∂
=∫∫
=∫∫
�� ��i i�
�� ��i i�
��i
��i
Faraday’s Law
Ampere’s Law
Gauss’s Law (Magnetic)
Gauss’s Law (Electric)
History Cont.
• Planck (1900) Quantizes
light energy
• Einstein (1905)
reintroduces light particles
(photons)
• 1920’s quantum
mechanics, light is both a
wave and a particle.
Wave Motion
2 2
2 2 2
1∂ ∂=
∂ ∂
y y
x v t
In general, waves obey the following equation
Question: What are some solutions?
= ±y( x,t ) y( x vt )For traveling waves
Electromagnetic Waves
Look in Appendix 1 for derivation
Maxwell’s equations lead to Electromagnetic wave equation
2 2
0 02 2
2 2
0 02 2
E E
x t
B B
x t
µ ε
µ ε
∂ ∂=
∂ ∂
∂ ∂=
∂ ∂
What is the speed of an Electromagnetic wave?
ε0=8.85x10-12 s2C2/m3kg µ0=4πx10-7 m kg/C2
Equating Electromagnetic wave
with light:
8
0 0
13x10 m / s
µ ε=
Maxwell: This velocity is so nearly that of light, that it seems we have strong
reason to conclude that light itself is an electromagnetic disturbance in the
form of waves propagated through the electromagnetic field according to
electromagnetic laws.
What is Light?
• Electromagnetic radiation
– The combination of propagating electric and
magnetic waves. But it is also a particle.
Electromagnetic Spectrum