# getRefractiveIndex

returns the susceptibility of choosen subsystem.

## Contents

- Syntax
- Description

## Syntax

- getRefractiveIndex(name)
- getRefractiveIndex(name,eps)

## Description

getRefractiveIndex(name,eps) works excatly analougus to the getSusceptibility method The refractive Index is calculated using the susceptibility by

where d denots the density of the medium. d is set to an arbitrary low value of d = 0.01, which corresponds to a gas.