For ten points, identify this dimensionless quantity, the coefficient of the trigonometric functions in Snell's law.
A power series expansion of this quantity in even powers of frequency is one of several Cauchy's equations. When this quantity lies it the upper half of an Argand diagram, the corresponding material is evanescent, and each of its parts can be found from the other via a relation derived from causality and named for Kramers and Kronig. The path-length integral of this property is stationary according to Fermat's principle and it can vary with applied electric field according to the Pockels effect. Its square is equal in general to the product of the relative permeability and relative permittivity of an optical medium. For ten points, identify this dimensionless quantity, the coefficient of the trigonometric functions in Snell's law.
A power series expansion of this quantity in even powers of frequency is one of several Cauchy's equations.
{index of refraction} (or {refractive index}; prompt on {n})