(Geometrical Optics)

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(Geometrical Optics)
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A beam of light generated by a laser. The beam is
visible because particles in the air have
scattered the light.
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Optical path
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n1 ? l1 n2 ? l2 n3 ? l3
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n (x,y,z)
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Convex elliptical
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PA - AP??
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An off-axis parabolic mirror element
The 2.4m-diameter hyperboloidal primary mirror of
the Hubble Space Telescope
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This solar-thermal electric plant in the Mojave
Desert uses long rows of parabolic mirrors to
focus the suns rays on oil-filled pipes,which
are located at the focal point of each mirror.
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A hyperbolic interface between air and glass
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Several hyperbolic lenses seen in cross section
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Comparison of spherical and paraboloidal mirrors
In the paraxial region
Polishing a spherical lens
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The reflected ray lies in the plane formed by the
incident ray and the normal.
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The bundle of rays from the top of the object
appears to originate from the image behind the
mirror
There is an image point for every source point
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For the woman to see her full-sized image, only a
half-sized mirror is needed.
Multiple reflections can be obtained with two
plane mirrors.
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Many emergency vehicles are reversed-lettered so
the lettering appears normal when viewed through
the rearview mirror of a car
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This array of corner reflectors was left on the
Moon by the Apollo 14 astronauts.
The incoming ray that strikes point A eventually
emerges along BD, parallel to the incoming ray.
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Refraction
A beam of light is refracted as it enters a tank
of water.
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(No Transcript)
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4????(Total Internal ReflectionTIR) ????
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Optical fiber
Light can travel with little loss in a curved
optical fiber, because the light is totally
reflected whenever it strikes the core-cladding
interface and because the absorption of light by
the core itself is small.
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A bronchoscope ??
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Light rays emanating from the bees body enter
the tube and, in part, are guided around the 90
degrees turn via TIR, eventually exiting through
the front surface and allowing you to see the bee.
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5??? (Prisms)
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A dispersive device
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To effect a change in the orientation of an image
or in the direction of propagation of a beam
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Rainbows
The colors of a rainbow result from dispersion in
the reflection of light from individual water
droplets in the air.
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The disks overlap, so it is relatively brighter
below the primary rainbow and above the secondary
rainbow, but darker between them.
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