Published:
When light interfaces from one media to another, its phase fronts (lines of constant phase) must stay continuous across the interface of the boundaries. This is true of all physical waves. From this fact, we actually derive Snell’s equation.
Published:
When an electromagnetic wave encounters a boundary between two dielectric media, part of the wave is reflected and part is transmitted. Due to energy conservation, the total power carried by the incident wave must equal the sum of the powers carried by the reflected and transmitted waves, assuming there is no absorption. Additionally, Maxwell’s equations require that the tangential components of the electric and magnetic fields remain continuous across the boundary. To describe this behavior quantitatively, I derive the Fresnel equations for s-polarized (transverse electric, TE) light, where the electric field is perpendicular to the plane of incidence.
Published:
“The vast interplanetary and interstellar regions will no longer be regarded as waste places in the universe, which the Creator has not seen fit to fill with the symbols of the manifold order of His kingdom. We shall find them to be already full of this wonderful medium; so full, that no human power can remove it from the smallest portion of space, or produce the slightest flaw in its infinite continuity.”
— James Clerk Maxwell