The index of refraction is given by: where = radian plasma frequency. .

for this is ordinary dispersion. For this is anomalous dispersion.

For plasma, so if there is no propagation.

• metals are shiny
• ionosphere reflects radiowaves of less than a few Mhz.

for transparent dielectrics: with .

solids and liquids: For of order 1, . This means tightly bound solids with loose valence electrons will be optically dense. The index, n is:

source psfile jl@crush.caltech.edu index linear_electrooptic_effect