Facile Scalable Fabrication and Multi-Modal Quantitatively Cross-Correlating Characterization of Gradient Refractive Index Optoelectronic Materials

Conversion of glasses into transparent glass-ceramic nanocomposites often involves complex engineering challenges where multiple competing factors such as the type, size, volume fraction, location, and composition of crystalline phases need to be precisely balanced out within a glass matrix. Especially, the development of a single optoelectronic component where its properties are required to spatially vary, such as gradient refractive index (GRIN) materials, bolsters the call for the new strategy on the fabrication and characterization of glass-ceramic materials that are scalable and multi-faceted, respectively. Here, we employ Ge-As-Pb-Se chalcogenide glasses as a testbed starting material and demonstrate a controlled crystallization process systematically developed for their conversion into spatially tuned glass-ceramic nanocomposites. Especially, we present a first-ever combination of a simplistic yet widely applicable gradient thermal treatment process and multi-modal quantitatively cross correlating microstructural-morphological-chemical-optoelectronic metrology, to develop large-scale transparent bulk GRIN glass-ceramic materials with refractive index contrasts up to ~ 0.2. Our findings are expected to provide new insights into the nature of complex crystallization process within glasses while opening the possibility of developing a cost-effective and scalable manufacturing process for spatially tailored optoelectronic components.