Investigating Optical Up-conversion Process of Erbium-doped Ceria Nanoparticles in Photonic Bilayer Bragg structure

This paper offers a thorough analysis using simulations, delving into the dual photonic impacts of using a Bragg stack in the optical upconversion (UC) process; the alteration of the local density of photon states (LDOS) and the amplification of local irradiance. We specifically investigate their influence on the upconversion quantum yield of the upconverter Er-CeO2nanoparticles (NPs). The Bragg stack being analyzed is composed of layers that alternate between TiO2 and Poly(methylmethacrylate) (PMMA), with the latter housing nanoparticles responsible for upconversion. The photonic effects are initially simulated independently and later integrated in a rate equation model to study its effect on the upconversion efficiency. This model accurately describes the kinetics associated with the upconversion (UC) processes within Er-CeO2 NPs. In order to ascertain the highest achievable upconversion efficiency across a spectrum of realistically feasible structures, adjustments are made to the refractive index of the active material within the con- fines of available materials. This work demonstrates the positive effect of photonic Bragg structure on the upconversion efficiency of Er-CeO2NPs.