Why does P-polarized light have an Ex component?

[geo_alchemist]

Let us imagine a surface, with X and Y axes on it and Z axis normal to it.
well, the theory, (in my particular case, some article) says that S polarized light, propagating along the x-directioin possesses only electric field components, E_i, parallel to the surface (||y-direction), i.e. transversal electric waves have E_i=(0, E_y, 0), while P-polarized light has E_i=(E_x, 0, E_z).

The question:

I understand that S-polarized light, propagating along x-direction has only electric field components, E_i, parallel to the surface. E_i=(0, E_y, 0), since in case of s-polarization E is perpendicular to plane of incidence.

Also I understand that P-polarized light, propagating in the same x-direction has E_z component, since in case of P-polarization E is in the plane of incidence.


what I do not understand is, why p-polarized light has E_x component.

 

[Andy Resnick]

A picture is worth 1000 words:

http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/tayu/ACT05E/img/05IMG/05_11.jpg

Does this help? Otherwise, please refer to the diagram and tell me which directions you are calling x,y, and z.

 

[geo_alchemist]

It seems that I understand bt it still is a bit foggy for me. Any further clarification would be greatfully appreciated.
Here is modified image with x, y and z.
http://img232.imageshack.us/img232/2802/0511copy.jpg

Uploaded with ImageShack.us

 

[Andy Resnick]

Do you see the essential difference between s- and p- polarization? It's not the (x,y,z) components per se, it's whether or not the electric field is in the plane of incidence.

 

[geo_alchemist]

Essential difference I see perfectly. what I need is to describe this difference in terms of Ex, Ey and Ez.

Anyway, now I understand it, thanks for picture ;)