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3 Wave Optics SCPY152 General Physics II June 19, 2015 Udom Robkob, Physics-MUSC

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Topics Light waves Phasor Huygenss principle Law of superposition Double slit interference Multiple slit interference Thin films Single slit diffraction Single hole diffraction Double slit diffraction Grating diffraction

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Light Waves Light waves Plane wave = sinusoidal field

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Phasor Rotating vector = phasor

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Law of Superposition Law of superposition

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Law of Superposition Phasor diagram

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Double Slit Interference Coherent light source = monochromatic light sources generate light waves in phase Young double slit experiment

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Double Slit Interference Path different y

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Double Slit Interference Path different y What is equation for destructive interference?

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Multiple Slits Interference In case of triple slit interference

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Multiple Slits Interference In case of triple slit interference Three phasors are determined

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Multiple Slits Interference In case of triple slit interference Three phasors are determined

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Multiple Slits Interference In case of triple slit interference Three phasors are determined Let try to analyze four slit interference pattern!

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Interference from Thin Films Let us determine thin transparence film of refractive index n and thickness d. There are interferences at the front side and back side of the film. We determine interference between light come from the front surface and the back surface of the film.

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Thin Film Interferences In case of front side interference The interference depends on path different 2d and phase different of the two light beams

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Thin Film Interferences In case of n>n o, the first beam has phase shift from reflection at the front surface but not the second beam Destructive Interference:

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Thin Film Interferences Exercise

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Thin Film Interferences Exercise

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Thin Film Interferences In case of non-uniform film

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Thin Film Interferences In case of non-uniform film In case of n>n 0, for destructive interference

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Thin Film Interferences Newtons rings R

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Thin Film Interferences Newton rings analysis

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Diffraction Phenomena We can see light diffraction in many places

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Huygenss Principle Huygenss principle Every point on the wave front becomes a new source of the wave"

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Single Slit Diffraction Single slit diffraction

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Single Slit Diffraction Phasor analysis

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Single Slit Diffraction Phasor analysis

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Single Slit Diffraction Phasor analysis-destructive interference Path different

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Single Slit Diffraction Phasor analysis-destructive interference Path different

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Double Slits Diffraction Double slit diffraction