Hello. My question/problem is this: I have a plane wave traveling in the positive z-direction through 3 different mediums. Also, medium 2 is comprised of a slab with thickness a. I want to express the electric and magnetic fields of the wave as it travels through these mediums. More specifically, I want to know how to express the electric and magnetic field inside the slab as it is influenced by the slab. I specifically want to know this because I am not sure how to do it. I want to express these equations because I would like to know the reflection and transmission of the wave as it passes the 3 different mediums. Because the incident wave will be reflected back and transmitted through the 3 mediums. If anybody could help me. Specially how to express the electric and magnetic field in medium 2 (slab), I would be extremely grateful!