Diffraction Grating: Does Light Excite Electrons or Pass Through Holes?

[gyroscopeq]

Simple question about this:

Say you have a wire diffraction grating. Does the incoming light excite the electrons in the metal, which scatter new light *or* does the incoming light simply pass through the "holes" in the mesh and get absorbed by the grating? I've seen it explained both ways, yet they seem incompatible.

Thanks!

 

[jerromyjon]

It is only the path separations which cause every photon to interfere with itself creating the diffraction you see.

 

[gyroscopeq]

It is only the path separations which cause every photon to interfere with itself creating the diffraction you see.

I get that. I had always understood these gratings as allowing the "original" light to pass through the holes in them, then interfere with itself. However, I recently read (Feynman Lectures) that the light excites the elections in the metal grating, and that is what emits the light which forms the pattern.