Fig. 1. Transmission spectra of high-index chalcogenide glass NBL-TQIR-1 (sample thickness of 2.5 mm). The photo of NBL-TQIR-1 chalcogenide glass sample with the diameter of Φ50-100 mm

Fig. 2. (a) Design scheme of dual-field MWIR optical system of traditional crystal materials, focal length of 60 mm, F#3; (b) Design scheme of lightweight medium wave dual-field optical system based on NBL-TQIR-1, focal length of 60 mm, F#3; MTF of traditional crystal materials optical system is calculated for (c) narrow field and (d) wide field; MTF of optical NBL-TQIR-1 system is calculated for (e) narrow field and (f) wide field

Fig. 3. (a) Design of traditional material medium/short wave uncooled confocal optical system, focal length of 50 mm, F#1, from front to rear, ZnSe, IG6, BaF₂, and IG4; (b) Design of medium/short wave cooled confocal surface optical system based on NBL-GRIN chalcogenide glass, 50 mm, F#1 lens, from front to rear, the two lenses are GRIN-NBL-27/NBL-12 and NBL-17, respectively; (c) MTF of traditional material medium/short wave optical system; (d) Sag Z diagram of the first diffractive surface of lens 4; (e) MTF of medium/short wave optical system

Fig. 4. (a) Design of traditional material medium/long wave cooled confocal optical system, focal length of 60 mm, F#3, four lenses from front to rear, ZnSe, Ge, BaF₂, and Ge; (b) Design of medium/long wave cooled confocal optical system based on NBL-GRIN chalcogenide glasses, focal length of 60 mm, F#3, the two lenses from front to rear are NBL-GRIN and NBL-22, respectively; MTF of traditional material is calculated for (c) MWIR and (d) LWIR wavebands; MTF based on NBL-GRIN is calculated for (e) MWIR and (f) LWIR