Light Diffraction, Interference and Polarization

Diffraction Diffraction is the bending of any wave including light. Easily seen when looking at shadows Every shadow’s edge is slightly blurry due to bending of light waves around the object

Problems with diffraction Microscopes that use light cannot see objects that are smaller than wavelength of light Diffraction makes the object very blurry Electron microscopes are used instead to avoid diffraction.

Interference When two waves interact, the waves may join to make a larger wave or cancel each other out

Diffraction Gratings An object with a multitude of closely placed slits. Separates light into the spectrum of colors Examples Bird’s feathers CD/DVD discs

Interference Thin films of liquid can act like diffraction gratings Examples Soapy water Gasoline on water

Polarization The alignment of transverse waves along the same axis. Occurs when the light reflects off a shiny surface Glass windows Water

Uses of Polarization Sunglasses 3-d movies glasses Polarized sunglasses have closely spaced vertical slits. This blocks light reflected from pavement or water sources 3-d movies glasses One eye is vertically polarized; the other is horizontally polarized.