ECE-1466%20Modern%20Optics%20Course%20Notes%20Part%201

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ECE-1466Modern OpticsCourse NotesPart 1

• Prof. Charles A. DiMarzio
• Northeastern University
• Spring 2002

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ECE1466 Modern Optics

• Instructor Chuck DiMarzio
• Office Hours Thu 2-4 or by appointment
• E-mail dimarzio _at_ ece.neu.edu
• Web Check frequently for new material
• http//ece.neu.edu/courses/ece1466/ece1466.html
• Course Mailing List Use for general questions
• mailtoece1466_at_gnoson.ece.neu.edu
• Send me e-mail and I will add your name.

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Lecture 1 Overview

• Introduction
• Why Optics?
• A bit of history
• Motivational Example Microscope
• Administrivia
• Course Layout
• Grading
• Syllabus

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Why Optics?
Index of Refraction
Absorption Spectrum of the Atmosphere
from Jackson
1mm
1nm
1mm
1mm
1m
Absorption Spectrum of Liquid Water
1nm
1mm
1m
1km
1mm
5
Earthlight
6
A Bit of History
Wave Theory (Longitudinal) (Fresnel)
Empirical Law of Refraction (Snell)
...and the foot of it of brass, of the
lookingglasses of the women assembling,
(Exodus 388)
Light as Pressure Wave (Descartes)
Transverse Wave, Polarization Interference (Young)
Rectilinear Propagation (Euclid)
Law of Least Time (Fermat)
Light Magnetism (Faraday)
Shortest Path (Almost Right!) (Hero of Alexandria)
vltc, Two Kinds of Light (Huygens)
EM Theory (Maxwell)
Plane of Incidence Curved Mirrors (Al Hazen)
Rejectionof Ether, Early QM (Poincare, Einstein)
Corpuscles, Ether (Newton)
1900
1800
1700
1600
2000
1000
0
-1000
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More Recent History
Laser (Maiman)
http//www.sff.net/people/Jeff.Hecht/chron.html
Hubble Telescope
http//members.aol.com/WSRNet/D1/hist.htm
Polaroid Sheets (Land)
Phase Contrast (Zernicke)
Erbium Fiber Amp
HeNe (Javan)
Optical Fiber (Lamm)
Optical Maser (Schalow, Townes)
GaAs (4 Groups)
Quantum Mechanics
FEL (Madey)
Speed/Light (Michaelson)
CO2 (Patel)
Holography (Gabor)
Commercial Fiber Link (Chicago)
Spont. Emission (Einstein)
Many New Lasers
2000
1990
1980
1970
1960
1950
1940
1930
1920
1910
8
Some Everyday Applications

• Illumination
• Signaling
• Cameras Film and Electronic
• Bar-Code Reader
• Surveying and Rangefinding
• Microscopy
• Astronomy

9
My Research Interests

• Biological and Medical Imaging
• Acousto-Photonic Imaging (DOT and Ultrasound)
• Optical Quadrature Microscopy
• Landmine Detection
• Laser-Induced Acoustic Mine Detection
• Microwave-Enhanced Infrared Thermography
• Environmental Sensing
• Optical Magnetic Field Sensor
• Underwater Imaging with a Laser Line Scanner
• Hyperspectral Imaging Laboratory Experiments

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Some Other Applications (1)

• Communication
• Lasers and Fast Modulation
• Fibers for Propagation
• Fast Detectors
• Dense Wavelength Diversity Multiplexing
• Free-Space Propagation (Not Much)
• Optical Disk Memory
• Lasers, Detectors
• Diffraction Limited Optics

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Some Other Applications (2)

• Photo Lithography for Integrated Circuits
• Short Wavelength Sources
• Diffraction Limited Optics
• Adaptive Optical Imaging
• Non-Linear Materials or Mechanical Actuators
• Velocimetry and Vibrometry
• Coherent Detection, Coherent Sources

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Some Other Applications (3)

• Hyperspectral Imaging
• Dispersive Elements
• Large Detector Arrays
• Fast Processing
• Medical Treatment
• Delivery
• Dosimetry

13
Some Recent Advances

• Laser Tweezers
• Optical Cooling
• Entangled-States
• Fiber-Based Sensors
• Optical Micro-Electro-Mechanical Systems

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Motivation Designing a New Microscope

• Its Not Just About Resolution
• Resolution Limited by Diffraction
• Its About What Is Measured
• Transmission, Reflection, Phase, Fluorescence,
  Polarization, Non-Linear Properties
• And About How Data Are Processed
• Registration, Deconvolution, Tomography,
  Parameter Estimation
• And About Measuring Everything at Once

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Contrast Features

• Material Properties
• Wavespeed
• Attenuation
• Birefringence
• Non-Linearity

• Composition What are the materials?
• Quantitative Measurements How much of each?
• Structure How they are arranged?
• Boundaries
• Shapes

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A Couple of Rules

• Frequency and Wavelength
• nlc where n is frequency, l is wavelength
• c is the speed of light.
• Photon Energy
• E hn where h is Plancks constant
• Materials Absorb and Emit Photons with
  Corresponding Changes in Energy

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Some Material Properties
Absorption
Emission
Fluorescence
2-photon
Energy
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3-D Fusion Microscope
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Interference and Quadrature Microscopy
CCD
Object
CCD
Laser Source
QWP
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Mouse Embryos with DIC
4-Cell Embryo
2-Cell
1-Cell
Fragmented Cell
Multi-Cell Embryo
Compacted Embryo
100 mm
Image by Carsta Cielich in Carol Warners
Laboratory at Northeastern University
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Mouse Oocyte with QTM
Unwrapped Phase
Amplitude
Phase
10027.jpg
3993.jpg
10028.jpg
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Some 3D Scanning Microscopes
thanks to Badri Roysam, RPI
Reflectance Confocal VivaScope 1000 - imaging
in vivo
Fluorescence Confocal
Two-Photon Microscope
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What Does Each Mode Contribute?

• DIC
• 2-D Structure
• QTM
• 2-D Phase, 3-D Index and Absorption
• RCM
• 3-D Structure
• LSCM
• 3-D Composition
• TPLSM
• 3-D Composition (Endogenous Fluorophores)

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Why Use This Example?

• Important Application Area
• Current Interest at Northeastern
• Coverage of Important Topics
• Geometric Optics
• Diffraction
• Interference
• Polarization
• Non-Linear Optics
• Lasers
• Signals and Noise

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Some Everyday Concepts (1)

• Specular and Diffuse Reflection
• Refraction

Diffuse
Retro
Specular
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Some Everyday Concepts (2)

• Imaging

Wavefronts
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High-School Optics
F
Image
Object
F
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Basic Geometric Optics

• Reflection and Refraction
• Imaging
• Real and Virtual
• Image Location Conjugate Planes
• Magnification
• Transverse, Angular, Longitudinal
• Reflecting Optics (Not much in this course)
• Refracting Optics

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Reflection
q
q
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Plane of Incidence

• Contains Normal
• Contains Incident Ray
• And Thus Contains Refracted Ray
• Is the Plane Shown in the Drawing
• Angles
• Defined from Normal

q
q
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Imaging

• First, Assume a Point Object
• Spherical Wavefronts and Radial Rays Define
  Object Location
• Find Image Location
• Real or Virtual?
• Next Assume an Extended Object
• Compute Magnification
• Transverse, Longitudinal, Angular

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Where Are We Going?

• Geometric Optics
• Reflection
• Refraction
• The Thin Lens
• Multiple Surfaces
• (From Matrix Optics)
• Principal Planes
• Effective Thin Lens
• Stops
• Field
• Aperture
• Aberrations

Ending with a word about ray tracing and optical
design.
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The Plane Mirror (1)
Extended Object
Point Object
q
B
B
q
q
h
x
x
A
A
A
A
-s
s
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The Plane Mirror (2)
Image is Virtual (Dotted lines converge) Erect
(mgt0), Perverted (can not rotate to object) but
not distorted (mmz)
Transverse Magnification
xx mx/x1
Longitudinal Magnification
dy
ds
dx
ds-ds mzds/ds-1
Angular Magnification
qq maq/q 1
dx
(refer to picture on left side of previous page)
dy
ds
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Refracting Surfaces (1)
Snells Law
50
Air to Water
n
45
n
Air to Glass
m
Air to ZnSe (10
m)
40
m
Air to Ge (10
m)
35
q
30
q
25
Angle of Refraction
20
15
10
5
0
0
10
20
30
40
50
60
70
80
90
Angle of Incidence
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Refracting Surfaces (2)
Snells Law
90
Water to Air
80
n
Glass to Air
n
m
ZnSe to Air (10
m)
m
Ge to Air(10
m)
70
60
q
50
q
Angle of Refraction
40
30
20
10
0
0
10
20
30
40
50
60
70
80
90
Angle of Incidence
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Sign Definitions
B

• Object Distance, s
• Positive to Left
• Image Distance, s
• For Refraction
• Positive to Right
• For Reflection
• Positive to Left
• Notation
• Capital Letter Point
• Lower Case Distance
• (Almost Always)

A
F
A
F
B
s
s
s
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Real and Virtual Images

• Real Image
• Rays Converge
• Can Image on Paper
• Solid Lines in Notes
• Virtual Image
• Extended Rays Converge
• Dotted-Lines in notes

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The Thin Lens (1)
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The Thin Lens (2)
Front Focal Length
Back Focal Length
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Special Case Thin Lens in Air
Lens Makers Equation with d 0
Lens Equation
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Imaging Systems
B
H
H
V
V
B
D
D
f
f
s
s
w
w
s, s are object and image distances w, w are
working distances
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Principal Planes with Bending
HHVV/3 holds, except for extreme meniscus
lenses. H, H in lens from plano-convex to
convex-plano. Mensicus lenses not common.
P
P
0.1/cm, z
0.5 cm, n1.5
1
2
12
0.4
0.3
0.2
0.1
p1, Power of Front Surface, /cm.
0
-0.1
-0.2
-0.3
-0.4
-2
-1
0
1
2
3
4
5
Locations V, V',H,H'
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Bending an IR Lens (Ge n4)
P
P
0.1/cm, z
0.5 cm, n4
1
2
12
HHVVX3/4 for n4, over a wide range of
bending. Meniscus lenses are more common in the
IR because of the high indices of refraction, as
we will see later.
0.4
0.3
0.2
0.1
p1, Power of Front Surface, /cm.
0
-0.1
-0.2
-0.3
-0.4
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
Locations V, V',H,H'
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Some Optical Failures
f
f
Right Focal Length, Wrong Principal Planes For
the Application
Meniscus Lens for Infrared Detector