School of Physics Lecture Demonstration Manual

Od-3 Diffraction (Fraunhaufer)

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


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



Click on pictures to enlarge.

Fraunhaufer diffraction Diagram


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.

Safety notes

Electrical safety 

Laser safety 

Sharps safety 


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