Huygens' principle
Intermediate
Each point on a wavefront is a source of secondary wavelets.
Every point on a wavefront acts as a source of secondary spherical wavelets; the new wavefront is their envelope. It explains reflection, refraction and diffraction.
Plane waves hitting a boundary and bending.
Ignores the backward wave (needs Kirchhoff).
In more detail
Huygens' principle states that every point on a wavefront acts as a source of secondary wavelets, and the new wavefront is their envelope. It explains reflection, refraction and diffraction.
Real-world uses
- Huygens' principle is used to construct wavefronts in optics and acoustics.
- It helps explain why waves bend around obstacles.
- Engineers use Huygens' principle to predict how a wave spreads through a gap or bends around an obstacle.
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Frequently asked questions
What are secondary wavelets?
Spherical waves emitted from each point on a wavefront.
Does it explain interference?
Yes, when combined with superposition, it explains interference patterns.
What is a wavefront?
A surface on which all points of a wave have the same phase, which moves forward as the wave travels.
Related topics in Optics
Reflecting telescope · Camera and f-number · Wave theory of light · Coherent sources · Young's double slit · Fringe width