{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Diffraction and Interference

Diffraction and Interference - Diffraction and Interference...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Diffraction and Interference Performed: 4/19/07, Due: 4/26/07 Theory: The term interference refers to any situation in which two or more waves overlap in space. In this experiment we examine light interference through diffraction. Diffraction is the group of interference patterns formed when light strikes a barrier that has an aperture or an edge. Interference effects such as those seen in diffraction cannot be understood with a particle model of light, and is explained using a wave model for light since interference is a wave property. Light also has particle properties which are evidenced by the photoelectric and Compton effects. Questions about propagation of light require a wave theory of light and many of the interactions of light with matter require a particle theory, so light is viewed as a wave-particle duality. In this experiment we analyze the waves aspects and behavior of light. Monochromatic light is light of a single color and thus of a single wavelength. Common light sources do not emit monochromatic light, but lasers are a nearly monochromatic source of light, with the familiar helium-neon laser with a wavelength range of the order of one part in one billion. Coherence is when two monochromatic sources of light have the same frequency with any definite, constant phase relation. The light emitted by a laser is also highly coherent. The coherence means that there are surfaces, in this experiment approximately planes, in which the light is in phase. When such light falls on a slit or slits, the electric field oscillates in phase over the area of the slit(s) and Huygen’s principle can be used to calculate where the transmitted light will interfere constructively and destructively. In this experiment it is assumed that the light incident on the aperture(s) is a monochromatic plane wave, and that the observing screen is are enough away that all the lines from the aperture(s) to a given point in the observed intensity parttern are essentially parallel. This is far-field of Fraunhofer diffraction. Slits are used in the diffractions
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}