Lecture 23: Polarization

Slides:



Advertisements
Similar presentations
You have been given a mission and a code. Use the code to complete the mission and you will save the world from obliteration…
Advertisements

Copyright © Cengage Learning. All rights reserved.
Optics, Eugene Hecht, Chpt. 8
Advanced Piloting Cruise Plot.
Chapter 1 The Study of Body Function Image PowerPoint
Chapter 7 Companion site for Light and Video Microscopy Author: Wayne.
1 Copyright © 2010, Elsevier Inc. All rights Reserved Fig 2.1 Chapter 2.
By D. Fisher Geometric Transformations. Reflection, Rotation, or Translation 1.
7.5 Glide Reflections and Compositions
Business Transaction Management Software for Application Coordination 1 Business Processes and Coordination.
Today’s summary • A new look at propagation and phase delays
Jeopardy Q 1 Q 6 Q 11 Q 16 Q 21 Q 2 Q 7 Q 12 Q 17 Q 22 Q 3 Q 8 Q 13
Jeopardy Q 1 Q 6 Q 11 Q 16 Q 21 Q 2 Q 7 Q 12 Q 17 Q 22 Q 3 Q 8 Q 13
Title Subtitle.
My Alphabet Book abcdefghijklm nopqrstuvwxyz.
0 - 0.
DIVIDING INTEGERS 1. IF THE SIGNS ARE THE SAME THE ANSWER IS POSITIVE 2. IF THE SIGNS ARE DIFFERENT THE ANSWER IS NEGATIVE.
FACTORING ax2 + bx + c Think “unfoil” Work down, Show all steps.
Addition Facts
Year 6 mental test 5 second questions
1 T. Kataoka, S. E. Day, D. R. Selviah, A. Fernández Department of Electronic and Electrical Engineering University College London, U.K. Polarization-Insensitive.
Points, Vectors, Lines, Spheres and Matrices
Negative Numbers What do you understand by this?.
ZMQS ZMQS
ABC Technology Project
Plane wave reflection and transmission
VOORBLAD.
Direct-Current Circuits
Squares and Square Root WALK. Solve each problem REVIEW:
© 2012 National Heart Foundation of Australia. Slide 2.
The x- and y-Intercepts
Lets play bingo!!. Calculate: MEAN Calculate: MEDIAN
Motion in Two and Three Dimensions
Chapter 5 Test Review Sections 5-1 through 5-4.
GG Consulting, LLC I-SUITE. Source: TEA SHARS Frequently asked questions 2.
SPH3UW Today’s Agenda Friction What is it?
Addition 1’s to 20.
25 seconds left…...
Torque Rotational Equilibrium Rotational Dynamics
Week 1.
Vector Algebra One Mark Questions PREPARED BY:
TOC 1 Physics 212 and 222 Magnetic Forces Magnetic Force on a Moving Charge Magnetic Force on a Current Carrying Wire.
We will resume in: 25 Minutes.
©Brooks/Cole, 2001 Chapter 12 Derived Types-- Enumerated, Structure and Union.
PSSA Preparation.
Rolling, Torque, and Angular Momentum
Mechanics Lecture 2, Slide 1 Vectors and 2d-Kinematics Continued Relevant Equations How to use them Homework Hints.
Sections 5.1 & 5.2 Inequalities in Two Variables
Now that we have determined the solutions to the differential equation describing the oscillations of the electric and magnetic fields with respect to.
Beam propagation in anizotropic crystals Optic axis of a crystal is the direction in which a ray of transmitted light suffers no birefringence (double.
Polarization - linear - circular
Chapters 14 & 18: Matrix methods. Welcome to the Matrix.
Polarization Jones vector & matrices
c = km/sec I F = I 0 x (cosθ) 2.
Chapter 5 Jones Calculus and Its Application to Birefringent Optical Systems Lecture 1 Wave plates Wave plates (retardation plates) are optical elements.
Silicon chip birefringence
Chapter 44 Polarization. Content of this Chapter About polarization Polarizing sheets Polarization by reflection Double refraction Circular polarization.
Review of Basic Polarization Optics for LCDs Module 4.
Tue. Nov. 11, 2008Physics 208, Lecture 211 From last time… EM waves Inductors in circuits I? + -
Polarization Jones vector & matrices
Physics 102: Lecture 15, Slide 1 Electromagnetic Waves and Polarization Today’s lecture will cover Textbook Sections Physics 102: Lecture 15.
Elliptical polarization. Linear polarization the two orthogonal components are in phase.
Phys 102 – Lecture 16 Electromagnetic wave energy & polarization.
Lecture 24: Polarization
Announcements I should have exams back to you on Fri.
Matrix treatment of polarization
Categories of Optical Elements that modify states of polarization:
Elliptical polarization
Presentation transcript:

Lecture 23: Polarization Physics 212 Lecture 23: Polarization

What makes EM waves Which of the following do not create EM waves? Constant current Accelerating electron. Electron orbiting a nucleus. Charged pith ball rotating on a string around a circle. E) Electron moving with constant velocity.

So far we have considered plane waves that look like this: From now on just draw E and remember that B is still there:

Linear Polarization

The intensity of a wave does not depend on it’s polarization: I could have also rotated the coordinate system such that x points along hat e! So Just like before

Polarizers The molecular structure of a polarizer causes the component of the E field perpendicular to the Transmission Axis to be absorbed. Animation

Two Polarizers since the second polarizer is orthogonal to the first, no light will come through. cos(90) = 0

Two Polarizers you can use a polarizer at an angle so that it takes a portion of the polarized light and basically lets the light through AT THAT ANGLE. Then, when the light reaches the second polarizer, it is no longer orthogonal to it.

What if we put many polarizers between? Applet polarizer What if we put many polarizers between?

There is no reason that f has to be the same for Ex and Ey: Making fx different from fy causes circular or elliptical polarization: At t=0 Example:

Circular polarization In Physics and Astronomy, we define left/right circular polarization if the light rotates cw/ccw as seen from the receiver (looking at the incoming light). In engineering we define it as seen from the emitter! As seen by emitter

Q: How do we change the relative phase between Ex and Ey? A: Birefringence: Anisotropic material. Light incident from different directions propagates at different speeds. Right hand rule By picking the right thickness we can change the relative phase by exactly 90o. This changes linear to circular polarization and is called a quarter wave plate

This modification does not change the intensity either: Right Handed Circular Polarization (at t = 0) This modification does not change the intensity either: So Just like before

Circular Light on Linear Polarizer Q: What happens when circularly polarized light is put through a polarizer along the y (or x) axis ? I = 0 I = ½ I0 I = I0 X Half of before

In case A you lose your horizontal component of the wave, however in B you retain both, just at a shift of pi/2.

Both Ex and Ey are still there, so intensity is the same QW Plate Both Ex and Ey are still there, so intensity is the same

Ex is missing, so intensity is lower Polarizer

What is the polarization of the light in Case 2 after it passed through the quarter wave plate? Linearly polarized Right circularly polarized (as seen by receiver) Left circularly polarized (as seen by receiver)

Right circularly polarized (CCW) as seen by emitter Left circularly polarized (CW) as seen by receiver.

Executive Summary: Polarizers & QW Plates: Birefringence RCP Circularly or Un-polarized Light Polarized Light Polarizers & QW Plates: Birefringence RCP

Calculation Light is incident on two linear polarizers and a quarter wave plate (QWP) as shown. What is the intensity I3 in terms of I1? fast y 45o x slow 60o I1 I2 I3 z Conceptual Analysis Linear Polarizers: absorbs E field component perpendicular to TA Quarter Wave Plates: Shifts phase of E field components in fast-slow directions Strategic Analysis Determine state of polarization and intensity reduction after each object Multiply individual intensity reductions to get final reduction. The purpose of this Check is to jog the students minds back to when they studied work and potential energy in their intro mechanics class.

Calculation (A) LCP (B) RCP (C) (D) (E) unpolarized Light is incident on two linear polarizers and a quarter wave plate (QWP) as shown. fast y 45o Light incident on QWP is linearly polarized at 45o to fast axis E1 x RCP slow LCP or RCP? Easiest way: Right Hand Rule: l/4 Ex Ey 60o I1 I2 I3 z What is the polarization of the light after the QWP as seen by emitter? (A) LCP (B) RCP (C) (D) (E) unpolarized x y The purpose of this Check is to jog the students minds back to when they studied work and potential energy in their intro mechanics class. Light will be circularly polarized after QWP Curl fingers of RH back to front Thumb points in dir of propagation if right hand polarized.

Calculation (A) I2 = I1 (B) I2 = ½ I1 (C) I2 = ¼ I1 Light is incident on two linear polarizers and a quarter wave plate (QWP) as shown. fast y 45o x E1 RCP slow Ex Ey 60o I1 l/4 I2 I3 z What is the intensity I2 of the light after the QWP? (A) I2 = I1 (B) I2 = ½ I1 (C) I2 = ¼ I1 AFTER: BEFORE: No absorption: Just a phase change ! Same before & after !

Calculation (A) LCP (B) RCP (C) (D) (E) unpolarized Light is incident on two linear polarizers and a quarter wave plate (QWP) as shown. fast y 45o x E1 RCP slow Ex Ey 60o E3 I1 l/4 I2 = I1 I3 z What is the polarization of the light after the 60o polarizer? (A) LCP (B) RCP (C) (D) (E) unpolarized x y 60o The purpose of this Check is to jog the students minds back to when they studied work and potential energy in their intro mechanics class. Absorption: only passes components of E parallel to TA (q = 60o) 60o Ex 3 Ey E3

Calculation (A) I3 = I1 (B) I3 = ½ I1 (C) I3 = ¼ I1 Light is incident on two linear polarizers and a quarter wave plate (QWP) as shown. fast y 45o x E1 RCP slow Ex Ey 60o E3 I1 l/4 I2 = I1 I3 = ½ I1 z What is the intensity I3 of the light after the 60o polarizer? The purpose of this Check is to jog the students minds back to when they studied work and potential energy in their intro mechanics class. (A) I3 = I1 (B) I3 = ½ I1 (C) I3 = ¼ I1 Ey E3 3 NOTE: This does not depend on q !! 60o Ex