Sellmeier equations

Dispersion of the refractive index of the amorphous film can be analyzed based on the Sellmeier equation,as follows ... 

The indices of refraction of LaCh have been measured by LaFrance (1970) and are given by the Sellmeier equation... 

The Sellmeier equation is a later development of Cauchy s work that handles anomalously dispersive regions, and more accurately models a material s refractive index across the ultraviolet, visible, and infrared spectrum. 

Sellmeier Equation An empirical relationship between refractive index and wavelength for a particular transparent medium. The equation is used to determine the dispersion of light in the medium. It was first proposed in 1871 hy W. Selhneier, and was a development of the work of Augustin Cauchy on Cauchy s equation for modeling dispersion. 

For common optical glasses, the refractive index calculated with the three-term Sellmeier equation deviates from the actual refractive index by less than 5 x 10 over the wavelengths range of365 nm to 2.3 pm, which is of the order of the homogeneity of a glass sample. Additional terms are sometimes added to make the calculation even more precise. In its most general form, the Sellmeier... 

The Sellmeier equation can also be given in another form ... 

A2 — Cl A2 — C2 Here, the coefficient A is an approximation of the short-wavelength (e.g., ultraviolet) absorption contributions to the refractive index at longer wavelengths. Other variants of the Sellmeier equation exist that can account for a material s refractive index change due to temperature, pressure, and other parameters. (Refractive index... 

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