Rare-earth-doped glasses have been demonstrated as highly promising scintillator materials, particularly for X-ray imaging applications. However, challenges such as high defect density, low luminescence efficiency, and poor spatial resolution remain, primarily attributed to high phonon energy, inefficient energy transfer (ET), and light scattering in glass materials. Herein, we report a successfully designed dual-sensitized codoped Gd-based oxyfluoride glass scintillator that can achieve high internal quantum efficiency (IQE, 97.5%), excellent X-ray luminescence (XEL) intensity (216% Bi₄Ge₃O₁₂), high optical transparency (approximately 90% at 550 nm), and good radiation stability by using Tb³⁺ as the luminescent center, synergistically incorporating Gd³⁺ and Ce³⁺. Specifically, the optimized glass scintillator can achieve a spatial resolution of up to 32.6 lp·mm⁻¹ for X-ray imaging, coupled with an exceptionally low detection limit of 1.03 μGy·s⁻¹. Additionally, the developed glass scintillator enables irregular-shaped and large-scale fabrication (diameter: 5 cm) that is difficult to accomplish with conventional scintillator materials. The developed material offers a new option for developing low-cost, high-performance glass scintillators for high-resolution X-ray imaging.

Mid-infrared light sources have some important applications in military and national economy, such as national defense safety, food safety, spectral analysis and so on. Recent research work on rare-earth element ions doped chalcogenide glasses and optical fibers mainly focuses on improving the solubility of rare-earth element ions, reducing the local phonon energy of rare-earth element ions and co-doping of sensitized ions. The mid-infrared fluorescence of rare-earth element ions such as Dy³⁺, Pr³⁺, Dy³⁺, Tb³⁺, and Sm³⁺ can be obtained in glass and optical fiber. This broadband mid-infrared fluorescence is applied in the sensing field to realize the sensing of gases such as CO₂ and CH₄. This review represented recent research progress on rare-earth element ions doped mid-infrared chalcogenide glasses and optical fibers. Various factors affecting the mid-infrared luminescence of chalcogenide glass fibers were discussed, i.e., the solubility of rare-earth element ions, phonon energy around rare-earth element ions, energy transfer between sensitized ions and impurity loss. The research progress of broadband mid-infrared fluorescence in the field of gas sensing was summarized. There are five deficiencies in the research of rare-earth element ions doped sulfur fiber gas sensor. Obtaining the mid-infrared laser in rare-earth element ions doped glass fiber is still a challenge. In addition to seeking the solutions from the perspective of active fiber preparation (i.e., matrix selection, rare-earth ions co-doping, local structure regulation, preform glass purification, etc.), some aspects of optical fiber grating writing technology, pump laser power and wavelength tuning were also concerned. Rare-earth element ions doped mid-infrared chalcogenide fiber as a promising optical material has a great application potential due to its advantages of compactness, compactness and economy.