Transcript MSEG 803 Equilibria in Material Systems

MSEG 667
Nanophotonics: Materials and Devices
1: Introduction
Prof. Juejun (JJ) Hu
[email protected]
References
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Principles of Nano-optics
 L. Novotny and B. Hecht, UD Library link
Fundamentals of Photonics
 B. A. Saleh and M. C. Teich, John Wiley & Sons, Inc.
Photonics: Optical Electronics in Modern Communications
 A. Yariv and P. Yeh, Oxford University Press
Waves and Fields in Optoelectronics
 H. A. Haus, Prentice-Hall, Pearson Higher Education
Photonic Crystals: Molding the Flow of Light
 J. D. Joannopoulos, S. G. Johnson, J. Winn, R. Meade, MIT link
Classical Electrodynamics
 J. D. Jackson, Wiley
Electromagnetic Wave Theory
 J. A. Kong, EMW Publishing
The class
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Sakai site
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Syllabus, announcements, lecture slides,
assignments, exam solutions will be posted on Sakai
UD Capture
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Class will be videotaped
Link to the videos will be posted on Sakai
Grading policies
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One mid-term: 25%
One final: 35%
Homework assignments: 10%
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Discussions are allowed and encouraged; but you
are supposed to complete the assignments
independently!
Design review projects: 30%
Exams
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Exams will be open book & open internet
No texting, no online chatting, no collaboration during
the exam
No exam questions can be
be solved simply by Wiki
or Google
Your answers are supposed
to be concise and precise
What exactly is “nanophotonics”?
Optics/Photonics
Microphotonics
Nanophotonics
Lens & prisms
Optical fibers
Nanoparticles
L >> l
L~l
L << l
Course content
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Basic theories
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Optical micro- and nano-cavities
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Electromagnetic wave theory
Guided wave optics
Diffractive optics
Resonant cavity basics
Photonic crystals
Nanophotonic chem-bio sensors
Light-matter interactions in the nanoscale
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Optical absorption
Classical dipole radiation
Spontaneous and stimulate emission
Course content (cont’d)
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Optics on surfaces and nano-structures
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Photonics of quantum-confined structures
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Surface plasmon-polaritons
Scattering theory
Localized surface plasmonic resonance: metallic nanostructures
Quantum dots and quantum wells
Carrier dynamics in quantum confined structures
Quantum well modulators
Numerical methods for nanophotonics
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FDTD, EME, BPM, FD, FEM, etc.
Course content (cont’d)
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Student proposed topics in optics or photonics
Examples:
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Optical design of solar cells
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What: antireflection coatings, light trapping,
quantum dot solar cells, nanowire cells
Why: PV is a promising renewable energy
source and everyone is talking about it
Infrared imaging/detection
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What: photodiodes, photoconductors, avalanche photodiodes,
detector noise, responsivity, spectral response
Why: this is my thesis topic; plus, it is cool to see what myself
looks like in an infrared camera!
Models of light
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Ray optics
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Light propagates in a straight
line
Wave optics (scalar wave
theory)
Electromagnetic wave optics
(vectorial wave theory)
Quantum optics
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Wave-particle duality: photons
Momentum:
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p k
Energy:
E 
The particle nature of light is most pronounced when l is small
Ray optics: a visual tool (λ << Lsystem)
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In a homogeneous medium, light travels along straight
lines (rays)
Reflection and refraction
http://www.lon-capa.org/~mmp/kap25/Snell/app.htm
Law of reflection: θr = θi
Snell’s law: nr sinΘr = ni sinΘi
Ray optics provide spatial intuition but no physical insight into the laws!
Reflection & refraction on curved surfaces
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Incident and reflection/refraction angles are taken with
respect to the surface normal
Optical force: radiation pressure
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Wave-particle duality of light
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Photons have momentum: p = h / λ
Force needs to be applied to change the propagation
direction of a photon: Δp = -F·t
Reflected ray
Incident ray
Reflected ray
Δp
F: radiation pressure
Incident ray
Radiation pressure in science fictions: solar sail
Count Dooku’s solar sailer:
Star Wars Episode II: Attack
of the Clones
Optical force: trapping of particles
• Stable trapping condition: creating a potential well
• Forces in opposite directions
Scattering force
light beam
focusing
lens
reflected light
reflected light
Δp
incident light
Gradient force
Fs
Fg
incident light
transparent
particle
Δp
refracted light
refracted light
Optical tweezers
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Move particles, live cells, microspheres …
Optical tweezers for
“A real-life implementation
of the evergreen arcade
game Tetris was obtained
by optically trapping 42
glass microspheres (1 μm
dia.) in a 25 μm x 20 μm
sized area under a microscope. Their positions are
then steered with a
computer.”
What is the magnitude of optical force you can obtain
with a 1 mW laser?