If we have a very thin sheet of conductor, and a plane EM wave incident upon it from a vacuum, it goes into the conductor and starts dying exponentially. Another result is that the E and B fields of the wave aren't in phase anymore (see Griffiths). Now, what happens when the wave reaches the other side? I assume it transmits some sort of energy/wave to the vacuum, but what happens because the E and B fields are probably not in phase at this boundary? Does a plane wave with E and B fields out of phase propagate into the vacuum? I kind of assumed this wasn't possible. Or do out of phase E and B fields propagate for a bit and then die out? Thanks!!