PHYS 131 Lecture Notes - Lecture 4: Rectilinear Propagation, Geometrical Optics, Physical Optics
14 Nov 2017
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Document Summary
Optical effects can be divided into two broad classes: light as rays without considering wave properties; this is geometric optics, light as fundamentally a wave; this is physical optics or wave optics. Wave effects are important when the size of the object interacting with a light wave is comparable in size to the wavelength of the wave. For example, light waves passing through a pinhole. Wave optics (or physical optics) are required to correctly describe this situation. The wave-lengths of visible light are small, of the order of a micron (10-6 m), so it is easy to find situations where the wavelength of light is smaller than the size of the interacting objects. For example, light passing through lenses or reflecting from mirrors. For these cases, we can use geometric optics. Geometric optics has a wide range of applications. (cameras, Ray: we can specify direction of a light wave"s propagation with a straight line.
