Spatial Ln ³⁺ ‐Enrichment in Nano‐Phases and kinetic Pulse‐Compression on Multiphoton Upconversion Pumping Toward UV Lasing Glass‐Ceramics

Abstract The multiphoton upconversion of near‐infrared (NIR) light into challenging UV emission is of great importance and interest for both fundamental research and advanced applications. However, the NIR‐to‐UV multiphoton upconversion process is inherently inefficient. In this work, a strategy is presented to enhance NIR‐to‐UV conversion by integrating spatial and temporal control of energy transfer (ET) in lanthanide‐doped transparent materials. Through a molecular dynamics simulation‐assisted glass‐ceramic design approach, the spatial distance is reduced between Yb‐Tm‐Gd ions and accelerated their ET rates, achieving a 267‐fold enhancement of UV emission at 311 nm. Furthermore, this is showed that energy depletion in intermediate excited levels and back ET can be suppressed through short pulse‐width excitation, thereby increasing the proportion of UV photons in upconversion emissions from 1.61% to 38.81%. Consequently, low‐threshold, room‐temperature random lasing at 311 nm under 980 nm ns laser excitation is realized. These findings establish a novel design framework for developing compact solid‐state UV lasers with practical applicability.