Photonic nano-antennas: Directive emission and quantum state transformation

We consider the general concept of quantum field quantization in the nano-antenna modeled as an atomic chain. We show that the transformation of quantum near-field to the far-field is accompanied by the transformation of the quantum state of light. As a result, transmitting and receiving antennas cannot be considered separately, which has no analogs in classical antennas. Such behavior stems from the transmitting antenna quantum state destruction via the signal detection by the receiving antenna.