11:00 AM - 11:30 AM
[16a-213-7] [INVITED] New development of chalcogenide glasses for infrared transmitting materials
Keywords:chalcogenide glass, Infrared transmitting materials, chalcohalide glasses
Recently, chalcogenide glasses have received much attention for the use in various optical equipment, such as infrared surveillance cameras, night vision cameras, thermal imaging systems, and so on. Remarkable progress are made in the technology of the chalcogenide glasses with excellent homogeneity, mold-formability, and mass-productivity. Among them, selenide-based glasses have been well developed for practical applications while new sulfide glass systems without selenium and arsenic, which are the most popular elements used in chalcogenide glasses, have been also investigated in the last decade. In this presentation, we introduce new As, Se-free sulfide glasses in addition to summarizing the current researches and developments on the chalcogenide glasses for application in the infrared region.
The As, Se-free sulfide glasses are based on the Ga-Sb-S systems with additional components such as Sn and MX (M=Cs, Ag, X=Cl, Br, I). Glasses are obtained in the pseudo-three component systems; the compositional area are ranging approximately 10 to 60 mol% of GaS3/2, 20 to 90 mol% of SbS3/2, and 0 to 50 mol% of the additional component. Glasses with some compositions have DT=Tc-Tg, the index for the thermal stability against crystallization, higher than 200 K, indicating that the glasses are expected to be suitable for mold-shaping. The transmission edge at the infrared region of these glasses are located around 13 um. Thus, the infrared transmission ranges of the glasses cover the so-called atmospheric windows. This was rather difficult for the conventional sulfide glasses, in which the transmission limits are located around 11 um.
The glass-forming systems based on Ga-Sb-S-MX are also interesting as a chalcohalide system, a fourth family of non-oxide glass systems. By the incorporation of halides into chalcogenide glasses, we expect to find new glass-forming systems having high performance for applications in the infrared optics. For instance, physicochemical properties such as refractive index are drastically varied by the incorporation of halides. This means that the designability in optics is increased using these infrared transmitting materials. On the other hand, it has been reported that the incorporation of halides sometimes induces inhomogeneity such as crystallization and phase separation in the chalcogenide glasses. Although these phenomena are undesirable for optical applications, investigations for the development of new functional glasses have been also carried out by using the induced inhomogeneity.
The As, Se-free sulfide glasses are based on the Ga-Sb-S systems with additional components such as Sn and MX (M=Cs, Ag, X=Cl, Br, I). Glasses are obtained in the pseudo-three component systems; the compositional area are ranging approximately 10 to 60 mol% of GaS3/2, 20 to 90 mol% of SbS3/2, and 0 to 50 mol% of the additional component. Glasses with some compositions have DT=Tc-Tg, the index for the thermal stability against crystallization, higher than 200 K, indicating that the glasses are expected to be suitable for mold-shaping. The transmission edge at the infrared region of these glasses are located around 13 um. Thus, the infrared transmission ranges of the glasses cover the so-called atmospheric windows. This was rather difficult for the conventional sulfide glasses, in which the transmission limits are located around 11 um.
The glass-forming systems based on Ga-Sb-S-MX are also interesting as a chalcohalide system, a fourth family of non-oxide glass systems. By the incorporation of halides into chalcogenide glasses, we expect to find new glass-forming systems having high performance for applications in the infrared optics. For instance, physicochemical properties such as refractive index are drastically varied by the incorporation of halides. This means that the designability in optics is increased using these infrared transmitting materials. On the other hand, it has been reported that the incorporation of halides sometimes induces inhomogeneity such as crystallization and phase separation in the chalcogenide glasses. Although these phenomena are undesirable for optical applications, investigations for the development of new functional glasses have been also carried out by using the induced inhomogeneity.