Is the Huygens principle applicable in a vacuum?

Huygens' principle, in optics, a statement that all points of a wave frontof light in a vacuum or transparent medium may be regarded as new sources of wavelets that expand in every direction at a rate depending on their velocities. read more

Huygens’ principle, in optics, a statement that all points of a wave frontof light in a vacuum or transparent medium may be regarded as new sources of wavelets that expand in every direction at a rate depending on their velocities. read more

Huygens’ principle, in optics, a statement that all points of a wave front of light in a vacuum or transparent medium may be regarded as new sources of wavelets that expand in every direction at a rate depending on their velocities. read more

According to Huygens' principle, a plane light wave propagates though free space at the speed of light, c Every point on a wave-front may be considered a source of secondary spherical wavelets which spread out in the forward direction at the speed of light. The new wave-front is the tangential surface to all of these secondary wavelets. read more

But let’s go back to the Huygens’ principle. It applies to the description of light as a wave. It is a theoretical model that is, nevertheless, useful for describing certain scenarios. read more