Infrared Chalcogenide Glasses

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Product Information

Reliable solutions for the infrared industry

Infrared glasses (IRG) offer excellent transmission in the shortwave IR (SWIR), midwave IR (MWIR), and longwave (LWIR) range. Physical properties such as low dn/dT and low dispersion enable optical designers to engineer color-correcting optical systems without thermal defocusing. The IRG family of chalcogenide glasses is optimized for pairing with the family of IR glasses and other IR materials to support cost-effective and high-performance optical designs. These glasses encompass the common IR transmission bands 3 - 5 μm and 8 - 12 μm, but can transmit as low as 0.7 μm. Furthermore, the IR glass series offered by SCHOTT can be processed using conventional grinding and polishing techniques, single point diamond turning or molding to support low- to high-volume component-level manufacturing.

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Advantages

Low dn/dT and low dispersion
Excellent transmission in SWIR, MWIR and LWIR
Customized coatings
Effective production from prototypes to mass volumes
Superior quality and repeatable performance proven by internal measurements and process controls of batch material
Effective performance for color correcting optical systems and athermal imaging designs

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Supply Forms

Infrared chalcogenide glasses are available as:

Supply Forms	Thicknesses	Dimensions
Typical forms of supply will depend on customer‘s requirements	up to 150 mm	diameter: up to 95 mm
Offering of polished blanks for sample parts	5 mm up to 30 mm	diameter: 10 mm up to 95 mm

	Infrared Chalcogenide Glasses
Material Properties	IRG 22	IRG 24	IRG 25	IRG 26	IRG 27
Composition	Ge₃₃As₁₂Se₅₅	Ge₁₀As₄₀Se₅₀	Ge₂₈Sb₁₂Se₆₀	As₄₀Se₆₀	As₂S₃
Density	4.41 g/cm³	4.47 g/cm³	4.66 g/cm³	4.63 g/cm³	3.20 g/cm³
Thermal expansion (20 – 100°C)	12.5 · 10^–6/K	20.0 · 10^–6/K	14.0 · 10^–6/K	21.4 · 10^–6/K	22.5 · 10^–6/K
Transition temperature	368 °C	225 °C	285 °C	185 °C	197 °C
Thermal change dn/dT*	94.8 · 10^–6/K (1 μm)	46.0 · 10^–6/K (1 μm)	79.2 · 10^–6/K (1 μm)	76.2 · 10^–6/K (1 μm)	15.6 · 10^–6/K (1 μm)
	67.7 · 10^–6/K (5 μm)	21.15 · 10^–6/K (5 μm)	62.0 · 10^–6/K (5 μm)	33.4 · 10^–6/K (5 μm)	-3.2 · 10^–6/K (5 μm)
	67.1 · 10^–6/K (10 μm)	20.3 · 10^–6/K (10 μm)	61.1 · 10^–6/K (10 μm)	32.2 · 10^–6/K (10.6 μm)	-3.7 · 10^–6/K (10.6 μm)
Refractive index	2.5971 (1 μm)	2.7249 (1 μm)	2.7284 (1 μm)	2.9316 (1 μm)	2.4841 (1 μm)
	2.5104 (5 μm)	2.6192 (5 μm)	2.6183 (5 μm)	2.7909 (5 μm)	2.4129 (5 μm)
	2.4968 (10 μm)	2.6090 (10 μm)	2.6030 (10 μm)	2.7781 (10 μm)	2.3873 (10 μm)