Michelson’s Interferometer An interferometer is a device that can be used to measure lengths or changes in length with great accuracy by means of interference fringes. We describe the form originally devised and built by A. A. Michelson in 188 I.Consider light that leaves point P on extended source S in and encounters beam splitter M. A […]
Iridescence of a Morpho Butterfly Wing A surface that displays colors due to thin-film interference is said to be iridescent because the tints of the colors change as you change your view of the surface. The iridescence of the top surface of a Morpho butterfly wing is due to thin-film interference of light reflected by thin terraces […]
Equations for Thin-Film Interference In this chapter we have now seen three ways in which the phase difference between two waves can change: 1. by reflection 2. by the waves traveling along paths of different lengths 3. by the waves traveling through media of different indexes of refraction When light reflects from a thin film, […]
Reflection Phase Shifts Refraction at an interface never causes a phase change- but reflection can, depending on the indexes of refraction on the two sides of the interface. shows what happens when reflection causes a phase change, using as an example pulses on a denser string (along which pulse travel is relatively slow and a lighter string […]
Interference from Thin Films The colors we see when sunlight illuminates a soap bubble or an oil slick are caused by the interference of light waves’ reflected from the front and back surfaces of a thin transparent film. The thickness of the soap or oil film is typically of the order of magnitude of the wavelength of the […]
Combining More Than Two Waves In a more general case, we might want to find the resultant of more than two sinusoidally varying waves at a point. The general procedure is this: 1. Construct a series of phasors representing the waves to be combined. Draw them end to end, maintaining the proper phase relations between adjacent […]
Intensity in Double-Slit Interference Equations 36-14 and 36-16 tell us how to locate the maxima and minima of the double-slit interference pattern on screen C of Fig. 36-8 as a function of the angle o in that figure. Here we wish to derive an expression for the intensity I of the fringes as a function of O. […]
Coherence For the interference pattern to appear on viewing screen C in Fig. 36-6, the light waves reaching any point P on the screen must have a phase. difference that does not vary in time. That is the case in Fig. 36-6. because the waves passing through slits SI and S2 are portions of the single light wave […]
Coherence For the interference pattern to appear on viewing screen C in the light waves reaching any point P on the screen must have a phase. difference that does not vary in time. That is the case in . because the waves passing through slits SI and S2 are portions of the s single light wave that […]
L.ocatlng the Fringes Light waves produce fringes in a Young’s double-slit interference experiment, as it is called. but what exactly determines the locations of the fringes’? To answer. we shall use the arrangement in . There. a plane wave of monochromatic light is incident on two slits SI and S2 in screen B; the light diffracts through the […]