From Classical Superposition of Waves to Quantum Interference: Three Level Quantum System for Two Entangled Photons

Properties and applications of a plasmonic cross-shaped nano-antenna is presented and compared to those of array of holes. A simple analytical model based on the superposition of waves are proposed and compared to the numerical results. A direct consequence of unequal path for two orthogonal surface waves leads to a coherent quantum interferometer with interesting properties. Mechanism behind the rotating surface charge densities and consequently, the formation of rotating resultant dipole moments is identified and the concept of Dipole-SPP-LSP-Stokes coupling is introduced. All of which leads to the most significant findings (a) foundation of a three-level quantum system for entangled photons, based on the polarization states of the transmitted light and (b) further encapsulation of the three-level quantum system into a continuous orthonormal set of pure quantum states (c) an inference on the nonexistence of spin in a single photon, hence the requirement of two photons to create such spin states.