Author(s): Benjamin Jarvis-Frain, Andy Schang, Fernando Quijandría, Ibrahim Nsanzineza, Dmytro Dubyna, C. W. Sandbo Chang, Franco Nori, and C. M. Wilson The generation of entangled photons through spontaneous parametric down-conversion (SPDC) is a critical resource for many key experiments and technologies in the domain of quantum optics. Historically, SPDC was limited to the generation of photon pairs. However, the use of the strong nonlinearities … [Phys. Rev. Lett. 137, 040201] Published Tue Jul 21, 2026