光電工程二 optoelectronic engineering...
TRANSCRIPT
光電工程二
Optoelectronic Engineering II http://mx.nthu.edu.tw/mingchang/
Instructor: 陳明彰LAs:??
Today’s class
Why are we here…?What’s this class about ?What do we need to do ?How do we plan on doing it ?
http://mx.nthu.edu.tw/mingchang/
Lots of information posted on the web.Check frequently for changes!
What we are going to cover this semester?
Grading• In-class participation (5%)
– Participation only – Graded (Reading quizzes, occasional graded clicker question)
• Homework (45%) (most of learning, collaboration helps but you need to write your own solutions) Late HW will not be accepted, but I will drop your lowest one HW. No other freebies!
• Project (15 %) May 24: 1:20pm
• Exams (35%)– (15% midterm/ 20% final): 1. April 19: 1pm-3:20pm.
2. June 14 : 1pm – 3:20 pm.– Final (30%): Jun. 12: 12:30pm – 3:30 pm
You must be able to make these dates so reserve this time on your calendar! If you need special accommodations: See me!
Note: In-class participation and weekly homework make up 40% of final grade. Grade strongly depends on showing up for class, doing reading, and doing homework every week.
Milestones
Comb laserFrequency stabilization/Laser
Light guided by Fibers
Blue Diode
Laser TweezersLaser cooling/ Laser
Holography 3D Imaing/Laser
Precision Measurement
CHEM
Super-resolutionImaging / Laser
Ultrafast camera / Laser
Trad’l Model of EducationInstruction viatransmission Individual (you!)Content
11
Course Transformation with LAs
Otero et al, Science 2006
Learning only comes as result of your effort!1. Reading before class- introduce ideas and terms.2. Analysis and discussion in class- explore, develop
basic ideas and understanding.3. Master and retain ideas through use in
extensive HW (4-6 hrs/wk)(collaboration good, but submit own work)
Model for learning
Learning only comes as result of your effort!
Constant efforts
(Homework, reading,
disussions …)
degradePatient:T.R.Schibli
Homework
Reading assignments:• For every class (typically 2 assignments per week).• Quizzes on reading assignments will be part of your
final grades
Written Homework:• Weekly. (Usually due in the class on Thursday.)• See class and course homepage for assignments!• Late HW will not be accepted! I will drop your
lowest (one) HW score, but no other freebies.
Written Homework:
Superposition
Temporal-‐Spatial Waves
Freezing Time
Light source
Electromagnetic waves
x
E
E-field (for a single color):
E(x,t) = E0 sin[ (2πx/λ ) ̶ ωt +φ]
λE0
φ
λ = 2πc/ω,
E
Bx
Wavelength λ of visible light is: λ ~ 350 nm … 750 nm.
ω = 2πf = 2π/T
Free physics simulations!http://phet.colorado.edu
Wave interference.jarRadio Waves.jar
Mirrors
Light source
EM-‐Waves in an interferometer
Light source
Semi-transparentmirror
L
L
Constructive interference
=+
Screen:
?
Esum(x,t) = ½ ·∙E0 sin(ωt+2πx/λ +φ) + ½ ·∙E0 sin(ωt+2πx/λ +φ) = ?
= E0 sin(ωt+2πx/λ +φ) = Elight source(x,t)
Light sourceLight source
L
L
Unequal arm lengths
ΔL/2ΔL
+ΔL/2
Destructive interference
=+
Screen:
?
Esum(x,t) = ½ ·∙E0 sin(ωt+2πx/λ +φ) + ½ ·∙E0 sin(ωt+2π(x+Δx)/λ +φ)
= ½ ·∙E0 sin(ωt+2πx/λ +φ) -‐ ½ ·∙E0 sin(ωt+2πx/λ +φ) = 0
if Δx = λ / 2:sin(x+π) = - sin(x)
Light sourceLight source
Moving mirror: What do you see?
Screen
ΔL
ΔL
Intensity
λ/2
Light sourceLight source
Tilted mirror: What do you see?Fringes!
Screen
Hint
Math Exercise
=?
=?
cos(x)+cos(x+phi)
http://mx.nthu.edu.tw/~mingchang/Courses/OP/Lecture_pdf/interference01.mp4
1.5cos(x)+cos(x+phi)
http://mx.nthu.edu.tw/~mingchang/Courses/OP/Lecture_pdf/interference02.mp4
Discussion
A*cos(x)+B*cos(x+phi)
Discuss the visibility ([Imax-‐Imin]/ Imax+Imin) as a function of amplitude (A & B)?
Case I : B=A
Case II : B=0.5A
Sum two waves with different wavelength ?@@
cos(1.1x)+cos(x)k1=1.1 k2=1
Period K
cos(1.2x)+cos(x)k1=1.2 k2=1
Period K
Relation between k1, k2 and K?
Discussion
Relation between k1, k2 and K?
