# Convention problem

1. Jun 20, 2003

### Josette

Hi!! I'm new to this forum.
The index of refraction of a medium can be expressed as n'-jn" or n'+jn" as per the convention chosen for the phase advance in time(n" stands for absorption). Am I right in saying that the complex reflection/transmission coefficient calculated as a function of frequency would be different for the 2 conventions???
Thanks for helping...

2. Jun 23, 2003

### shchr

Hi! lonely question!
I don't understand what you mean by convention chosen for the phase advance in time. Anyway, the convention should be determined so that transmitted light is correctly described as attenuated one. The complex transmission/reflection coefficient may differ from convention to convention. But transmittivity and reflectivity calculated from those coefficients should not differ. Because transmittivity and reflectivity are measureable quantities. If those differ from convention to convention, physics changes by convention used to describe the phenomena. I think it is unacceptable.