Classical-to-quantum transition in multimode nonlinear systems with strong photon-photon coupling
Yue‐Xun Huang, Ming Li, Ke Lin, Yan‐Lei Zhang, Guang−Can Guo, Chang‐Ling Zou
Abstract
With advanced micro- and nanophotonic structures, the vacuum photon-photon coupling rate is anticipated to approach the intrinsic loss rate and lead to unconventional quantum effects. Here, we investigate the classical-to-quantum transition of such photonic nonlinear systems using the quantum cluster-expansion method, which addresses the computational challenge in tracking large photon number states of the fundamental and harmonic optical fields involved in the second-harmonic generation process. Compared to the mean-field approximation used in the weak-coupling limit, the quantum cluster-expansion method solves multimode dynamics efficiently and reveals the quantum behaviors of optical parametric oscillations around the threshold. This paper presents a universal tool to study quantum dynamics of multimode systems and explore the nonlinear photonic devices for continuous-variable quantum information processing.