Sumit Majumdar
Last Activity: 9 Years ago
This is given by the standard Cauchy relation:

wherenis the refractive index, λ is the wavelength,B,C,D, etc., arecoefficientsthat can be determined for a material by fitting the equation to measured refractive indices at known wavelengths. The coefficients are usually quoted for λ as thevacuum wavelengthinmicrometres.
Usually, it is sufficient to use a two-term form of the equation:

where the coefficientsBandCare determined specifically for this form of the equation.