Refraction index vs. wavelength?

[jaejoon89]

How does the refraction index vary with wavelength?

For example, if you take light that initially has just one wavelength and disperse it through a prism and calculate the different indices for each wavelength. I'm guessing they'll be different... Is it linear? exponential? etc.

 

[horatio89]

I'm not sure of the exact physics defining the relationship between the refractive index and the wavelength, but there is an empirical formula relating these two variables known as Cauchy's Formula:

n = A + B/(lambda)^2, where A and B are constants, n is the refractive index at wavelength, lambda.