Mind boggled that this article comes up now. Been working on similar tech recently, and the question of non-linearality arose right away. The discussed conclusi

Mind boggled that this article comes up now. Been working on similar tech recently, and the question of non-linearality arose right away. The discussed conclusion was "impossible". Yet I was able to design a crude NAND gate. So there has to be non-linearality it the quantum nature of diffraction and interference.