The Huygens principle determines that each wavefront acts as a new source, generating new waves. This explains, for example, the phenomenon of diffraction.
Christian Huygens (1629-1695) was a Dutch mathematician, physicist, and astronomer who patented the first pendulum clock (1656), produced powerful lenses capable of detecting one of Saturn ‘s moons, and developed work related to the wave theory of light .
The so-called Huygens principle says that each point on a wavefront works as a new source, producing waves that propagate with the same frequency, speed and in the same direction as the original waves.
The image above represents waves propagating on the surface of the water, for example. Each line corresponds to a wavefront that moves to the right. According to the Huygens principle, each highlighted point on the wavefront behaves like a new source, which makes the wavefront maintain its shape, as long as there are no obstacles to be overcome.
This principle is behind the explanation of the phenomenon of diffraction , according to which waves have the ability to circumvent obstacles .
Waves undergoing diffraction
In the image above, parallel wavefronts are diffracted as they pass through the slit. It can be seen that the ripples reach the regions opposite the obstacles, and this is possible because each point of the wavefront behaves as a source of new waves, following the principle established by Huygens.