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Explore the principles of interference, wave superposition, and diffraction in physical optics. Learn about thin film interference, double slits, and mirror equations. Discover applications like Newton's rings and X-ray diffraction.
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26 Interference & Diffraction--Physical/Wave Optics Thin film interference
Superposition & Interference Superposition: The net response at a given place and time caused by two or more stimuli is the sum of the responses which would have been caused by each stimulus individually (wikipedia) Key factor: phase.
Double Slits Interference-1 Fringes
Double Slits Interference-2 Mirror Equation
Interference in Thin Film Note: when nb > na, reflected wave undergoes an additional half cycle (i.e., l/2) phase shift.
Example: Interference Fringes (note: additional l/2 phase shift from the bottom reflection)
Diffraction—Reality Fresnel diffraction: near-field diffraction Fraunhofer diffraction: far-field diffraction
Fresnel & Fraunhofer: Single Slit Huygens’s Principle: Every point of a wave front may be considered the source of secondary wavelets that spread out in all directions with a speed equal to the speed of propagation of the waves.
Multiple Slits & Diffraction Gratings Constructive interference or bright fringes occur: Destructive interference or dark fringes occur:
Circular Apertures & Resolving Power First Dark Ring occurs
Resolving Power Rayleigh’s Criterion (increase D or reduce l could improve the resolution)
Ch 26 Homework Answers to multiple choice problems Problems: 1, 6, 11, 15, 25, 27, 47