School of Physics Lecture Demonstration Manual

Od-4 Diffraction (Fresnel)

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

Aim

To demonstrate the diffraction pattern of various objects subject to the Fresnel conditions (near field diffraction).

Apparatus

Diagrams

Click on pictures to enlarge.

Fresnel Diffraction Diagram

Description

When the source or the image plane are too near the diffracting object for the curvature of the wavefronts to be negligible Fresnel diffraction prevails. The experimental setup above produces these conditions. Diffracting objects are placed at O.

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