Hi guys! Was wondering if anyone was confident with Fresnel equations for a refractive index interface. From what I understand: Assume incoming normal plane wave travelling in z-direction and polarised in x plane. Assume z=0 is the plane that separates two materials: n_1 and n_2 (refractive index) I think the Fresnel solution for the wave should go: Ex = (for z>0) exp(-i*k0*n_1*z)+r*exp(i*k0*n_1*z) (for z<0) t*exp(-i*k0*n_2*z) the RED term representing the normal incident component and the GREEN term represents the reflected component which only exist in the n_1 half and the BLUE term representing the transmitted component which only exists in the n_2 half. I am uncertain about if I should be adding both the incident and reflected term (for z>0) as long as they are travelling in different directions or if I need to subtract them. i.e. should it be RED+GREEN or RED-GREEN? As I already have defined them to travel in opposite directions. Any thoughts? Many thanks!