Diffraction

Diffraction is the energy-conserving deviation of Waves due to interaction with an obstacle.

Common Observation

This effect is the most prominent with Plane Waves, which are emitted from Lasers, and also are approximated by distant point sources (which would emit Spherical Waves).
Ocean Waves are also approximately plane waves, which is why the effect is prominent there too. The reason why we do not observe diffraction more in everyday life is because most light sources do not emit plane waves.

Edge Diffraction

Or that they bend around corners. This is called Edge Diffraction

Ocean Waves

Intuition is very helpful

Uncertainty

Any Fourier Transform implies the Scale Theorem implies the Uncertainty Principle. Fraunhofer Diffraction uses the Fourier Transform. Therefore, Fraunhofer Diffraction implies the Uncertainty Principle. Specifically, in the case of 1 slit, an uncertainty principle between:

• The slit width
• The diffraction pattern width

The smaller the slit, the larger the diffraction angle and the bigger the diffraction pattern

2 Slit Diffraction

See 2 Slit Experiment

See also

Diffraction Grating Huygen’s Principle Fresnel Diffraction Fraunhofer Diffraction 2 Slit Experiment