Boosting Nd3+ emission in Nd/Al/Y co-doped silica glass by mid-range localized environmental manipulation

Abstract

Improving the repetition frequency of high-energy lasers is vital to promote the development and application of high-energy lasers, and its key lies in finding the laser gain media with excellent thermal shock resistance and high emission cross-section. Rare-earth ion (RE3+)-doped silica glass, whose thermal shock parameter is 1.5 times higher than that of yttrium aluminum garnet (YAG) crystals, is expected to satisfy this criterion after enhancing the emission intensity of RE3+. Nevertheless, modulating the spectral properties of RE3+ in rigid silica glass networks poses a significant challenge. Herein, we propose a mid-range localized environmental manipulation approach, which dramatically changes the microscopic symmetry of RE3+ from amorphous to the desired crystal structures for emission enhancement. As a representative, Nd/Y/Al co-doped silica glasses were prepared and heat-treated for different durations to form different mid-range localized environments, which were demonstrated by transmission electron microscopy, electron paramagnetic resonance tests, and Judd-Ofelt theory analysis. The results show that Nd3+ enters the YAG structure in favor of its emission enhancement. After optimizing the mid-range local environment of Nd3+ to balance fluorescence enhancement with fluorescence quenching and Rayleigh scattering, the emission intensity increases by 300%. Our work suggests that the mid-range localized environmental manipulation approach is extremely promising for promoting the development of high-energy and high-repetition-rate lasers. Furthermore, this approach can be generalized to adjust the emission characteristics of other RE3+-doped glasses and fibers.