# Non Linear Optics (tensors)

1. Jun 11, 2007

### n0_3sc

1. The problem statement, all variables and given/known data
a) What does the tensor nature of susceptibility mean? Ie. the $$xxxx$$ in:
$$\overline{P}=\epsilon_0\chi_{xxxx}\overline{E}$$

b) What does the 3 vertical dots mean in: $$\chi^{(2)}\vdots\overline{E}$$?

3. The attempt at a solution
a) I understand that $$\overline{P}=\epsilon_0\chi_{xx}\overline{E}$$ means the first x corresponds to the component of P and the second x relates to the polarization of the Electric Field. But what do the other x's mean?

b) No clue...

Last edited: Jun 11, 2007