Breakthrough in laser glass: A rational path to designing complex materials

A research team from the South China University of Technology has developed an innovative statistical modeling approach that accelerates the development of advanced rare-earth-doped laser glasses. Applying neighboring glassy compounds (NGCs) model, the team accurately predicted the local structural environments and luminescence properties of complex glass systems, reducing experimental trial-and-error. The NGCs model was used to establish the composition-structure relationship and populate the composition-property space. Finally, multi-luminescence property charts are generated to select compositions that satisfy multiple constraints, thus facilitating the rational design of chemically complex laser glasses for targeted applications. This versatile methodology paves the way for discovering next-generation laser materials with superior performance, expanding the horizons of glass science and technology.

Rare-earth (RE) doped glasses are key materials in modern photonics, finding widespread applications in telecommunication, solid-state lasers, and optical amplifiers due to their unique luminescent properties such as high efficiency, broad emission spectra, and excellent thermal stability. However, the development of these functional glasses remains a significant challenge, which is still relying on traditional trial-and-error methods, which are often time-consuming and limited in their predictive capacity. The main reasons for this are as follows: (i) The amorphous topological structure of glass remains largely enigmatic, and has been recognized as one of the 125 Most Challenging Scientific Issues by Science. (ii) The complexity of glass structure renders the study of the medium-range order (MRO) and short-range order (SRO) structures of RE ions challenging, further complicating laser glass design. (iii) The design of new laser glasses is not solely based on a single target property. These limitations highlight a critical need for more versatile, predictive frameworks capable of accurately estimating the luminescent properties of complex, RE-doped glasses. Such methodologies must bridge the gap between microscopic structural features and macroscopic optical behaviours in a manner that is both physically interpretable and computationally efficient.

The Solution: The researchers reported a new strategy for the design of laser glass: the surroundings of RE ions within chemically complex laser glasses are regarded as a statistical collection of their corresponding NGCs configurations. Based on this concept, they introduced an NGCs model in which the structural characteristics and luminescent behaviors of RE-doped glasses are quantitatively described through ensemble-averaged contributions of these NGCs. Specifically, for a given glass system, both the structural characteristics and luminescent behaviors of glasses with compositions across the entire composition space can be anticipated by referencing only a finite set of NGCs. To illustrate the predictive capabilities of the NGCs model, two local structural parameters, the pair distribution function (g(r)) and structure factor (S(Q)), were predicted and compared with those generated from molecular dynamics (MD) simulations. Furthermore, the NGCs model enabled the estimation of four representative luminescence metrics, effective linewidth (Δλ_eff), emission cross-section (σ_e), absorption cross-section (σ_α), and radiative lifetime (τ_rad), which were subsequently validated through comparison with experimental measurements. It was observed that the NGCs model closely reproduces the results of the MD simulations and experiments for Er³⁺-doped quaternary germanate glass system.

The Future: Future research will extend the NGCs model to predict other physical properties of glass, such as thermal properties and mechanical properties, thereby expanding the model's potential in the field of glass design.

The NGCs model reported here is applicable to any RE-doped laser glass system and can be used to: (i) understand the key structure features influencing glass luminescence properties and establish the composition-structure relationship, (ii) populate the composition-property space of chemically complex glass and provide insights into the underlying physics governing glass luminescence, and (iii) generate multi-luminescence property charts to guide the optimization of laser glass performance. The NGCs model allows for the high-throughput screening of luminescence properties, thereby enabling rational design of chemically complex glass systems, particularly in unexplored composition regions.

The Impact: The NGCs model establishes the composition-structure-property relationship for chemically complex laser glasses, opening new avenues for the discovery of next-generation laser glass materials.

The research has been recently published in the online edition of Materials Futures, a prominent international journal in the field of interdisciplinary materials science research.

Reference:  Zhenjie Lun, Minbo Wu*, Di Zuo, Haojun Zou, Dongdan Chen*, Shanhui Xu, and Zhongmin Yang*. Rational design of chemically complex laser glasses via neighboring glassy compounds model[J]. Materials Futures, 2025, 4(4): 045601. DOI: 10.1088/2752-5724/adff9e