Broadband mid‐infrared emission from Cr2+ in crystal‐in‐glass composite glasses by Hot Uniaxial Pressing

Cr2+‐doped II‐VI crystals have witnessed an excellent gain media for continuously tunable and femtosecond‐pulsed lasers. Despite this, major challenges persist toward realizing ultrabroad emission bandwidth and efficient Cr2+‐doped fiber due to the valence diversity of Cr, especially in chalcogenide glasses. Here, we propose to prepare Cr2+:ZnSe/As2S3‐xSex composite glasses by Hot Uniaxial Pressing (HUP), a method that sinters uniformly mixed crystal and glass powders into geometrically designed composite chalcogenide glasses. The densification of the composite glasses reached 99.88%, indicating that a few or none pores remain. Our research shows that Cr2+:ZnSe crystals have good performance in chalcogenide glasses, and the composite glasses have the potential to be made into mid‐infrared–doped fibers. It was demonstrated by scanning electron microscopy (SEM) and X‐ray diffraction (XRD) that the composite glasses have a uniform Cr2+:ZnSe distribution and no crystal disintegration. The transmittance of the composite glasses was significantly improved by tailoring the refraction index. The mid‐infrared (MIR) fluorescence and decay of the glasses were measured. The lattice constant was measured, calculated, and discussed to reveal the influence of sintering process on lifetime.