Cooperative absorption model for photon avalanche upconversion
Phys. Rev. A 112, 013522 – Published 21 July, 2025
DOI: https://doi.org/10.1103/96n8-6hk6
Abstract
Photon avalanche (PA) is a nonlinear process that presents a large growth of the upconversion fluorescence intensity signal and a strong absorption of the excitation light source occurring in lanthanide-doped systems. Conventional excitation schemes may introduce unwanted detrimental effects such as linear transmission losses and thermal effects. Here, a model is proposed in which the triggering mechanism for the PA effect is the absorption of a single photon by a pair of neighboring ions. The proposed model was studied using a rate equation system that describes the population dynamics of the electronic states of praseodymium ions in a silica fiber. The theoretical simulations confirm the presence of transmission attenuation and PA upconversion fluorescence when the lanthanide ions are at a short distance (a few angstroms), which guarantees the necessary PA positive feedback condition: a large cross-relaxation energy transfer rate among the lanthanide ions.
