might there be some interesting optical properties?

I mucked about with radio a fair bit years ago - so maybe a bit of a side-track but thinking in terms of something that might behave a bit like an array of antennas but on an atomic scale... add something "non-linear" to that picture (eg changes in "states" in the behaviour of electrons around those atoms causing something at a known frequency to be emitted or absorbed?).. and the thought of lthat in the context of something that could look like a tiny delay line ..

gets the imagination going anyway...