# Raman transition - Index of refraction

1. Sep 4, 2012

### Oamitt

When one calculate the real part of the index of refraction for a specific multilevel atom one would use the following formula:
$$Re(n(\Delta))=1+\frac{N e^2}{8\pi \epsilon_0 m\omega} \sum_i \frac{\Delta_i}{\Delta_i^2+(\gamma/2)^2}K_i$$
Where $K_i$ is the C-G coefficient.

My question is as follow:
How can I calculate this index of refraction in the case of a Raman transition? a.e. in the case where there is a coupling between two fields to create an otherwise forbidden transition.