School of Physics Lecture Demonstration Manual

Od-3 Diffraction (Fraunhaufer)

Published: Wednesday 15 March 2006 - Updated: Monday 28 March 2011

Aim

To demonstrate the diffraction pattern of various objects subject to the Fraunhaufer conditions (far field diffraction).

Apparatus

Diagrams

Click on pictures to enlarge.

Fraunhaufer diffraction Diagram

Description

As long as both the incoming and outgoing waves approach being planar (differing therefrom by a small fraction of a wavelength over the extent of the diffracting object), we obtain Fraunhaufer diffraction. The experimental setup to achieve these conditions is displayed above. Diffracting objects are inserted after the collimator.

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