Optics Tools

A collection of C programs for calculating index of refraction, Brewster angle etc

Programs in the collection

sellmeier: calculate index of refraction using Sellmeier's equation
sellmeier_n1: calculate dn/dlambda using Sellmeier's equation
sellmeier_n2: calculate d^2n/dlambda^2 using Sellmeier's equation
laurent: calculate index of refraction using Laurent's equation
laurent_n1: calculate dn/dlambda using Laurent's equation
laurent_n2: calculate d^2n/dlambda^2 using Laurent's equation
compressor: calculate edge to edge distance of a prism compressor as a function of the material in the optical path and prism material.
brewster-prism: calculate the angle of a brewster prism.

Source code

Download the source code here.

The programs are written in ANSI-C and should compile with any C compiler. A Makefile is provided for the use gcc and gnu-make. Compiling the programs is as simple as moving the zip-file to some directory and typing there

> unzip optics-tools.zip
> make all

Under any UNIX flavor this works out of the box. Under Mac OS X you'll need Apple's Xcode. Under Windows the min-gw environment will do the job. You may of course also import the sources into any other C compiler environment.

Sellmeier equation

The Sellmeier equation is 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 by W. Sellmeier, and was a development of the work of Augustin Cauchy on Cauchy's equation for modelling dispersion (source Wikipedia).

(Source CVI Melles Griot)

Laurent equation

For some media the Laurent series gives better results.

(Source CVI Melles Griot)

External Links

An XLS file with dispersion coefficients and other optical properties of all Schott glasses.