2024/03/13 by Elkin A. Santos, Maximilian A. Weissflog, Santos, Elkin A. +7 · 1 citation
Engineering · Physics and Astronomy · #FOS: Physical sciences #Mechanical and Optical Resonators #Nonlinear Optical Materials Studies #Optics (physics.optics) #Photonic and Optical Devices #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2403.08633
openalex publication_date 2024/03/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We develop a fully vectorial and non-paraxial formalism to describe spontaneous parametric down-conversion in nonlinear thin films. The formalism is capable of treating slabs with a sub-wavelength thickness, describe the associated Fabry-Pérot effects, and even treat absorptive nonlinear materials. With this formalism, we perform an in-depth study of the dynamics of entangled photon-pair generation in nonlinear thin films, to provide a needed theoretical understanding for such systems that have recently attracted much experimental attention as sources of photon pairs. As an important example, we study the far-field radiation properties of photon pairs generated from a high-refractive-index nonlinear thin-film with Zinc-Blende structure, that is deposited on a linear low-refractive-index substrate. In particular, we study the thickness-dependent effect of Fabry-Pérot interferences on the far-field radiation pattern of the photon pairs. We also pay special attention to study of entanglement generation, and find the conditions under which maximally polarization-entangled photon pairs can be generated and detected in such nonlinear thin-films.