7/30/2019 Chapter 1 Propagation
1/29
Welcome to Physics 461: OpticsInstructor: Dr. Yongchen Sun
Office: Akeley 117C
Ph#: 605- 677-5063
SD Optics 12
Lectures: Old Main, Room 204, TTh 2:00 - 3:15pm CT, attendance
is strongly encouraged. If you miss a class, you are responsible to
obtain handouts and homework assignments
: - : -
You are welcome to drop in or call outside my office hours but Imay not always be available.
7/30/2019 Chapter 1 Propagation
2/29
Fundamentals of Optics, 4th edition by Jenkins and
White
Equipment: OSA optics discovery kit $17.95/kit
http://www.edmundoptics.com/optics/optical-
lenses/lens-kits/optics-discovery-kit/1865
Old text last u dated in 1976. Can et chea er used
books.
Please make an effort to read the relevant text chapter
before you come to class.
There are also other useful texts. Please also review
your introductory physics text like Halliday and Resnick
SD Optics 12
7/30/2019 Chapter 1 Propagation
3/29
Other useful textsBorn Principles of Optics
Fowles Introduction to Modern Optics
Hecht Optics, 4th edition
Jenkins Fundamentals of Optics
Klein OpticsMeyer- Arendt Introduction to Classical & Modern Optics
Meyers Encyclopedia of Lasers and Optical Technology
Miloni Lasers
Moore Building Scientific Apparatus
O'Shea An Introduction to Lasers and their Applications
SD Optics 12
ea emen s o o ern p ca es gn
Optical Soc. of America Handbook of OpticsRay The Photographic Lens
Ray Photographic Optics
Ray Photographic Lenses and Optics
Siegman Lasers
Siegman An Introduction to Lasers and Masers
Silfvast Laser fundamentalsStrong Concepts of Classical Optics
Vaughan The Fabry-Perot Interferometer
Waynant Electro-Optics Handbook
Yeh Handbook of Fiber Optics
BYU Optics Online
7/30/2019 Chapter 1 Propagation
4/29
Lecture homework Doing problems is a necessary part of learning. Look over as manyproblems as you can from the text and check your answers in the
back of the book.
Increased proficiencyaccompanied by increased speedis also
important, both to your growth as a student and in the competitive
work environment one faces today.
SD Optics 12
Typically one homework set per week with an explicit due date
Please staple sheets together, otherwise please write your name in
the upper right corner of every sheet you turn in
Solutions will be posted on the web NO LATE HOMEWORK WILL BE ACCEPTED after solutions have been
posted
Your homework will be graded by me
7/30/2019 Chapter 1 Propagation
5/29
Homework gradingThe homework will not be graded in detail, but checked for
completeness.
0 - minimal effort
1 - reasonable effort, but serious mistake in physical reasoning
2 - physics ok, but serious math error
SD Optics 12
3 - completely correct, perhaps minor math error
Cooperation with your classmates is strongly encouraged.
Discussing and explaining physical concepts will give you a
higher level of understanding. However, everything you turn inmust be your own work.
7/30/2019 Chapter 1 Propagation
6/29
Exams 2 midterm exams: 44 % (22 % each)
final exam (comprehensive): 33 % all exams in class
the final exam carries
SD Optics 12
extra weight and replacesthe midterms if the score
is higher than your
average midterm exam
score.
you can bring your own
equation sheet (single
sided letter size)
7/30/2019 Chapter 1 Propagation
7/29
Explain your reasoning
SD Optics 12
Please show your work to receive full credit.
Empty pages earn you zero mercy points.
7/30/2019 Chapter 1 Propagation
8/29
Grading
2 Midterm exams 44 %
Final exam 33 %
Homework 23 %
SD Optics 12
B 80 - 89 %
C 70 - 79 %
D 60 - 69 %
F < 60 %
These are guaranteed. However, depending on the overall
class performance, curving can move these boundaries
substantially. The class average will typically be B.
7/30/2019 Chapter 1 Propagation
9/29
Class web page!
There, you can find
1. Posted (pdf format): Syllabus, homework solutions
2. Posted (pdf format): Lectures, (please dont print them
The website will point to the D2L site for the class:
Use the BOR username and password to login.
SD Optics 12
out!) 3. Class Announcements
Get into the habit of checking this Web page often!
7/30/2019 Chapter 1 Propagation
10/29
Math pre-requisitesI will only have limited class time available to teach you mathematics or
cover the basic physical concepts. Here is a list of what you mightwant to review:
Freshman-Sophomore Physics sequence (Physics 211/Physics 213)
Math - differential equations; calculus of derivatives and integrals(225)
SD Optics 12
complex plane, standard manipulations of complex numbers, andEuler's relation: ei = cos + isin
Geometry and trigonometry
Basic Fourier series/Fourier analysis/Fourier integral concepts will beintroduced in the course.
7/30/2019 Chapter 1 Propagation
11/29
Where to go for help??
See the syllabus, which covers this! See Me!!! Room UAK 117C.
Preferably during office hours. Or call me on the
SD Optics 12
.
My door is open for you, but you must make an
effort to come in.
7/30/2019 Chapter 1 Propagation
12/29
To succeed in this course
READ the book, which
cost you many $$$!
WORKthe assignedhomework problems
SD Optics 12
WORK extra problems
COME TO CLASS
7/30/2019 Chapter 1 Propagation
13/29
Geometrical Optics
Classical Properties of LightRectilinear Propagation-Light rays travel straight
7/30/2019 Chapter 1 Propagation
14/29
A Pinhole Camera Image
7/30/2019 Chapter 1 Propagation
15/29
Speed of Light-Fizzeau
Fizzeauc=312,000 km/s
Present
c=299,792,458 m/s
7/30/2019 Chapter 1 Propagation
16/29
Speed of light in matterThink of time sequence
Wire across slit as ref.
E from M1
Foucault 1850
1 2
E2 from M2 with water in T
v = 225000 km/s in water
(Michelson, 1907 Nobel)
v=299706 km/s in air
7/30/2019 Chapter 1 Propagation
17/29
Index (indices) of refraction
Ratio between the speeds in vacuum and in
matter cv
n =
Optical density (high for larger index in this book)
Not universal (Other def for absorption)
Glass 1.52-1.72 (1.47 quartz)
water 1.333 (4/3)
air 1.000 (1.000292 in the violet)
7/30/2019 Chapter 1 Propagation
18/29
Optical Path or
Optical Path Length (OPL)
d v t=
nd nvt ct = =
nd =Define OPL
Total OPL
A direct measurement of
total travel time
' ' '' ''nd n d n d = + + +
7/30/2019 Chapter 1 Propagation
19/29
Reflection and RefractionAll angles def. rel. N
Law of reflectionAngle of reflection equals to Angle
of incidence and is in the same
Snells Law of refraction
n for first medium and n for second medium
Relative index n sometimes used. Note the
notation. Of course, it doesnt matter if n=1.
sin '
sin ' '
n vconst
n v
= = =
7/30/2019 Chapter 1 Propagation
20/29
Small angle approximation
For small angles sin=
'
'
n
n
=
Symmetrical Snells law
sin 'sin 'n n =
7/30/2019 Chapter 1 Propagation
21/29
Graphical Construction-refractionAccurate
Two arcs-radii prop. n,n
Extend incident ray to meet
n arc at R
Draw ray parallel to N to
meet n arc at P
refracted ray
Proof of accuracy
Since OR/OP=n/n and sin()=sin, so
sin ' sin( )
OR OP
=
'
sin ' sin
n n
=
7/30/2019 Chapter 1 Propagation
22/29
Principle of Reversibility
If the ray goes backwards, the law of reflection
and refraction still holds.
But deal with the main ray only.
7/30/2019 Chapter 1 Propagation
23/29
Fermats Principle 1st proposed
From point A to point B, light takes the shortest
path (OPL smallest), because nature is economical
Modified
The path the light takes an extreme path (max,min, inflection)
First variation (like the first derivative) is zero
Paths around the real one equal to the real one tofirst approximation
7/30/2019 Chapter 1 Propagation
24/29
Fermats principle-plane reflection
7/30/2019 Chapter 1 Propagation
25/29
Fermats principle-elliptic reflector
7/30/2019 Chapter 1 Propagation
26/29
Fermats principle-plane refraction2 2 2
2 2 2
2 2 1/2 2 2 1/2
' '
( )
' '[ ( ) ] '[ ' ]
nd n d
d h p x
d h xn h p x n h x
= +
= +
= +
= + + +
2 2 1/2 2 2 1/2
want
'( 2 2 ) 2 0
2[ ( ) ] 2[ ' ]
'( 2 2 ) 2 0
2 2 '
( )'
'
sin 'sin ' Snell's law
t
n np x x
h p x h x
n n
p x xd d
p x xn n
d d
n n
=
+ + =+ +
+ + =
=
=
7/30/2019 Chapter 1 Propagation
27/29
Color (chromatic) dispersionDifferent color of light experience different indices of refraction
Fraunhofer lines traditionally used for labeling
More modern labelling may use round numbers in wavelength
Special materials may be labeled at specific wavelengthsLook up Sellmeier equation and Sellmeier coefficients
7/30/2019 Chapter 1 Propagation
28/29
Dispersive power and index
Crown glass as an example
At small angles
1.52933F
n = 1.52300D
n = 1.52042C
n =
' ' 0.00891F C F C
n n =
' 1 0.52300n =
Dispersive power
Dispersive index
1
F c
D
n nV
n
=
1D
F c
nv
n n
=
7/30/2019 Chapter 1 Propagation
29/29
Homework for chapter 1
1, 5, 10, 13, 18
Bonus problem 3 and rewrite 3rd paragraph of
section 1.3
ue next ues ay e ore c ass