Wave Optics

Light behaves as a wave

Light behaves as a wave. The wave model explains reflection, refraction, interference, diffraction, and polarisation. It also predicts that when light

A wavefront is a surface

A wavefront is a surface of constant phase. For a point source it is spherical, and far from the source it can be treated as plane. The direction of e

Each point on a wavefront acts

Each point on a wavefront acts as a source of secondary wavelets, and the forward envelope of these wavelets gives the new wavefront at a later time.

Using wavefront geometry

Using wavefront geometry, the speed ratio and angle ratio satisfy sin i over sin r equals v1 over v2. In refractive-index form, n1 sin i = n2 sin r. W

For light going from denser

For light going from denser to rarer medium, the critical angle satisfies sin ic = n2 over n1. If the angle of incidence becomes greater than ic, no r