PHYS 131 Lecture Notes - Lecture 20: Christiaan Huygens, Physical Optics, Huygens–Fresnel Principle
14 Nov 2017
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Document Summary
Physical optics involves phenomena where the wave nature of light is essential. This occurs when the light must pass through openings that are similar in size to its wavelength. Using rays (as in ray tracing) is fine as long as the light is interacting with objects much larger than its wavelength. But when light interacts with small things (barriers, pinholes, slits, etc) comparable in size to , we have to understand how the wavefronts can get distorted and bent: this property is called diffraction. This is the realm of physical optics, aka wave optics. We can predict ho(cid:449) wa(cid:448)efronts propagate: hu(cid:455)gens" principle: Formulated by the dutch physicist christiaan huygens (1600s) Hu(cid:455)gens" principle e(cid:454)plains ho(cid:449) light propagates through openings: The phase of one wave to another wave is a measure of the offset between the two waves (i. e. , how out of sync" they are) If the peaks and troughs of two waves line up, they are in phase": constructive interference.
