又翘课了。。。。

抄点板书赎下罪

Quantities

, , ,

, , ,

Maxwell Eq.

Linear media & isotropic media

Media gives the relation between , and ; similar for , and

Linear media means and are linearly related to and

Define relative permittivity and relative permeability (in Gaussian unit, ):

Here about Gaussian Unit there're some little problems, better see here

In general, and are tensors, when and , the media is isotropic

Maxwell Eq. in isotropic media

Assume that , , then

light speed in media: , where is the refractive index

Dispersive media

, where is the response function

similarly,

Causality:

Fourier transformation

Similarly,

We have ,

with

Dispersive relation

So for E.M. wave of a specific frequency , the Maxwell Eq. gives the wave equation

Plane wave solution:

TBD