Ultrabright Upconversion in Thermally Crystallized BaYF5:Yb,Er Glass-Ceramics via Dopant Enrichment for...

All-optical data encoding provides a route to ultrafast, low-energy photonic memory and computation, yet its implementation is hindered by weak nonlinearities and low emission efficiencies in conventional materials. Upconversion luminescence offers strong nonlinear behavior, but typical hosts suffer from inefficient energy transfer, dilute and randomly distributed dopants, and complex excitation demands. Here, we report thermally crystallized BaYF5:Yb,Er glass-ceramics that overcome low upconversion efficiency and dopant inhomogeneity through controlled Er3+ enrichment within BaYF5 nanocrystals. Thermal crystallization reduces interionic distances, promoting cooperative Yb3+-Er3+ sensitization and Er3+-Er3+ energy migration. The combination of theoretical modeling and experiments shows efficient population of high-energy emitting states, yielding ultrabright upconversion emission with enhancement factors of 113-, 118-, and 110-fold for the blue, green, and red channels under 980 nm excitation. Optimized nanocrystals also prolong emission lifetimes, suppress nonradiative relaxation, and produce clear saturation behavior. Leveraging strongly nonlinear responses, power- and pulse-width-modulated excitation enables precise control of both spectral and temporal outputs, forming a highly reconfigurable platform. This allows multidimensional data encoding and implementation of fundamental optical logic gates with high fidelity and self-referenced decoding. The system offers robust, secure, and scalable functionality for advanced all-optical information processing applications.