Rotating 2D Grating Couplers

If I use a 2D Grating Coupler component on my model and rotate it, am I to understand that it only applies to a 2D space or does it expand across the surface?

I want to have a plane surface (xy) with a grating structure built up in the z direction in 2D, rotated to some angle between x and y, and then send y polarized light normal (z) at the structure to read the transmission in the x polarization.

Is this clearly worded?

I assume that this topic is on discussion in this post (Rotating a 2D grating). Please continue the conversation there.

It is. I did not know what the response times are like or which might have been the better forum to post in. Would you like this one deleted?