Yes, we do have some pretty good theories for designing metamaterials. From what I can remember (and quickly look up on the net), one of the leading theories is

Yes, we do have some pretty good theories for designing metamaterials. From what I can remember (and quickly look up on the net), one of the leading theories is called transformation optics, and finding a coordinate transform to a coordinate system where the path you want light to take is a straight line. You can work out what your metamaterial has to look like from that coordinate transform. I probably have some of the details of the technique wrong, I am trying to remember a talk from a year ago. If you want more detail, look at John Pendry's papers (he is probably the leading theorist in metamaterials). http://www3.imperial.ac.uk/people/j.pendry http://www3.imperial.ac.uk/people/j.pendry