Group velocity and reflective index relationship

[JayKo]

how these two are related to each there? if refractive index is given as a function of angular frequency, how both are related? reflective index= omega*c / k.anyone?

 

[Claude Bile]

Group velocity is equal to;

$$\frac{d\omega}{dk}$$

Where

$$k = \frac{k_0}{n}$$

Where $k_0$ is the free-space wave-vector and $n$ is the refractive index of the medium.

Claude.

 

[JayKo]

hi Claude, thanks :D :D ;)