Transcript Light - Introduction to Physical Optics

Is that a Mirage…
or am I just seeing things?
An introduction to Physical Optics
Light - Introduction to Physical
Optics
• Reflection, Refraction, Snell’s Law,
Dispersion and the Wave-Particle Debate
(Chp 33)
• Polarization (Chp 33)
• Some applications to Biology and technology
• Interference and Diffraction (Chp 35)
The Wave-Particle Debate
Newton
Huyghens
• light consists of small
“massy” particles or
corpuscles that travel in
straight lines, are subject to
forces as one would expect
of particles but also have
additional vibratory
properties that can be used
to explain dispersion, color
produced by oil slicks and so
• light propagates as a wave
disturbance through the
ether - an unseen, elastic
medium pervading all of
space. Light will add, cancel
and share properties
common to all waves.
on.
Huyghen’s Principle
... every point on a primary wavefront
serves as the source of spherical
secondary wavelets propagating in the
forward direction such that the primary
wavefront at some later time is the
envelope of these wavelets. Further,
the wavelets advance with a speed and
frequency equal to the primary wave at
each point in space.
Mirages...
• Optical
– inferior
– superior (Fata Morgana)
• Acoustic
Optical Mirages
• Water on the Road?
• Fata Morgana
• Build your own
mirage!
Picture Gallery
Acoustic Mirages
• The Call of the Loon?
• Voices on the Lake?
• Combine refraction, dispersion and
reflection
• Illustrate subtle wave-properties of light as
well
Rainbow Gallery
•
•
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Spectral Order
1st and 2nd orders
Alexander’s Dark Band
Supernumeray rings
• Note the spectral order:
violet inside, red outside
• Faint outer rings is the 2nd order ring or
secondary bow. What do you notice about
the spectral order?
• Look at the sky brightness between the
primary and secondary bow.
• Beneath the primary bow there are subtle
repetitions of green and violet. These
“extra” arcs are called supernumary arcs.