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Infrared graded‐index (GRIN) lenses are desirable for realizing miniaturization and lightweight of infrared imaging systems. Chalcogenide glasses have excellent infrared transparency, good rheological property, and large refractive index range, making them preferred materials for infrared GRIN lenses. In this work, aiming to find thermally matched chalcogenide compositions with high refractive index contrast for preparing GRIN glasses by the stacking diffusion approach, we investigated characteristic temperature, thermal expansion coefficient and refractive index of Ge‐As‐Se and Ge‐As‐Se‐Te glasses, optimized the glass compositions, and evaluated the feasibility of preparing GRIN glass using the optimized chalcogenide glass powders. It is found that Ge20As20Se20Te40 and Ge12As22Se66 glasses have similar softening temperature (247°C vs. 249°C), reasonably difference of thermal expansion coefficient (3.8 ppm/K), and large refractive index contrast (∼.48). The glass powders with composition xGe20As20Se20Te40‐(1‐x) Ge12As22Se66 can be hot‐pressed into glass disks with good transmittance at the same temperature and pressure. Graded refractive index profile is formed near the interface between the layers after the co‐pressed glass is thermally treated. These results demonstrate the prospect of the compositions for preparing infrared GRIN glasses. [ABSTRACT FROM AUTHOR]

Gradient refractive index materials (GRINs) are rapidly evolving in optical achromats and compact imaging systems. And GRINs with multi-band imaging mean higher integration for advanced optical imaging systems. In this paper, GRINs covering mid-wave infrared (MWIR) and long-wave infrared (LWIR) were prepared by thermal diffusion method based on Ge 20 Se 80-x Te x glasses. Similar glass transition temperatures (ΔT g = 1 °C) and coefficients of thermal expansion (ΔCTE = 5.47 ppm/K) permit efficient bonding and diffusion processes between the glasses. The GRINs were visualized by infrared imagers, and the axial diffusion results were accurately characterized by Raman spectroscopy and energy dispersive spectrometer (EDS). The refractive index difference (Δn) of the GRINs reaches 0.23 and the diffusion depth reaches 3.53 mm. Diffusion coefficients and activation energy were calculated and discussed. Dispersion property is initially evaluated by Abbe number and partial dispersion. [ABSTRACT FROM AUTHOR]