chapter 1 propagation

7/30/2019 Chapter 1 Propagation

1/29

Welcome to Physics 461: OpticsInstructor: Dr. Yongchen Sun

Office: Akeley 117C

Ph#: 605- 677-5063

[email protected]

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.


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


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


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


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.


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)


7/29

Explain your reasoning

SD Optics 12

Please show your work to receive full credit.

Empty pages earn you zero mercy points.


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.


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!


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.


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.


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


13/29

Geometrical Optics

Classical Properties of LightRectilinear Propagation-Light rays travel straight


14/29

A Pinhole Camera Image


15/29

Speed of Light-Fizzeau

Fizzeauc=312,000 km/s

Present

c=299,792,458 m/s


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


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)


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 = + + +


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

= = =


20/29

Small angle approximation

For small angles sin=

'

'

n

n

=

Symmetrical Snells law

sin 'sin 'n n =


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

=


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.


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


24/29

Fermats principle-plane reflection


25/29

Fermats principle-elliptic reflector


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

=

+ + =+ +

+ + =

=

=


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


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

=


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

chapter 1 propagation

Documents