Optics

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Fundamental of OpticsLAMPA 502

• Prof. Walid Tawfik
• Office

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Course reference

• Introduction to Optics, F. L. Pedrotti

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Course Information

• Grading
• ASSIG 5
• Attendance 5
• Mid EX1 30
• Final Test 60
• total 100

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Course content sequence
Week Topic Lecture Exercises Practical
1 Introduction to geometrical optics 2 - -
2 The ray approximation in the ray optics 2 - -
3 Mathematical treatment of some optical phenomena such as reflection and refraction 2 - -
4 Huygenss Principle 2    
5 Dispersion 2    
6 Total Internal Reflection 2    
7 Fundamentals of wave optics 2 - -
8 Theoretical formulation of wave superposition Term paper exam 2 - -
9 Introduction to diffraction patterns 2 - -
10 Theoretical formulation of Diffraction Patterns from Narrow Slits and Resolution of Single-Slit and Circular apertures Mid-term Exam 2    
11 Theoretical formulation and conditions for wave interference from single and double slits (Youngs experiment) 2 - -
12 Introduction to polarization of light and its applications 2 - -
13 Applications of diffraction of light 2    
14 Applications interference of light 2    
  Total 28    
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Nature of Light
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Nature of Light

• Particle
• Isaac Newton (1642-1727)
• Optics
• Wave
• Huygens (1629-1695)
• Treatise on Light (1678)
• Wave-Particle Duality
• De Broglie (1924)

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Young, Fraunhofer and Fresnel(1800s)

• Light as waves!
• Interference
• Thomas Youngs (1773-1829) double slit experiment
  
• see http//members.tripod.com/vsg/interf.htm
• Diffraction
• Fraunhofer (far-field diffraction)
• Augustin Fresnel (1788-1827) (near-field
  diffraction polarization)
• Electromagnetic waves
• Maxwell (1831-1879)

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Max Plancks Blackbody Radiation (1900)

• Light as particles
• Blackbody absorbs all wavelengths and
  conversely emits all wavelengths
• The observed spectral distribution of radiation
  from a perfect blackbody did not fit classical
  theory (Rayleigh-Jeans law) ? ultraviolet
  catastrophe

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Cosmic black body background radiation, T 3K.
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Plancks hypothesis (1900)

• To explain this spectra, Planck assumed light
  emitted/absorbed in discrete units of energy
  (quanta),
• E n h??
• Thus the light emitted by the blackbody is,

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Luis de Broglies hypothesis (1924)

• Wave and particle picture
• Postulated that all particles have associated
  with them a wavelength,

• For any particle with rest mass mo, treated
  relativistically,

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Photons and de Broglie

• For photons mo 0
• E pc
• Since also E hf

• But the relation c ?ƒ is just what we expect
  for a harmonic wave

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Wave-particle duality

• All phenomena can be explained using either the
  wave or particle picture
• Usually, one or the other is most convenient
• In OPTICS we will use the wave picture
  predominantly

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Propagation of light Huygens Principle (Hecht
4.4.2)

• E.g. a point source (stone dropped in water)
• Light is emitted in all directions series of
  crests and troughs

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Terminology

• Spherical waves wave fronts are spherical
• Plane waves wave fronts are planes
• Rays lines perpendicular to wave fronts in the
  direction of propagation

Planes parallel to y-z plane
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Huygens principle

• Every point on a wave front is a source of
  secondary wavelets.
• i.e. particles in a medium excited by electric
  field (E) re-radiate in all directions
• i.e. in vacuum, E, B fields associated with wave
  act as sources of additional fields

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Huygens wave front construction
Construct the wave front tangent to the wavelets
What about r direction? See Bruno Rossi Optics.
Reading, Mass Addison-Wesley Publishing Company,
1957, Ch. 1,2 for mathematical explanation
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Plane wave propagation

• New wave front is still a plane as long as
  dimensions of wave front are gtgt ?
• If not, edge effects become important
• Note no such thing as a perfect plane wave, or
  collimated beam