Broad IR Transmission
Selected compositions support MWIR and LWIR applications, with useful spectral ranges extending from the near infrared beyond 12 µm.
Infrared Optical Material
Chalcogenide Glass
Moldable Infrared Glass for Compact, High-Performance Optical Systems.
A family of infrared-transmitting glasses engineered for thermal imaging, sensing, spectroscopy, laser delivery, and precision molded optics.
Why Chalcogenide Glass
Design Flexibility Across Mid-Wave and Long-Wave Infrared
Chalcogenide glasses combine broad infrared transmission with glass-like processing and composition-dependent optical properties, giving designers an adaptable alternative to crystalline infrared materials.
Precision Moldability
Suitable grades can be precision molded into aspheric and diffractive surfaces for compact, high-volume optical assemblies.
Tailorable Properties
Refractive index, dispersion, thermal behavior, and transmission vary by composition, enabling material selection around system priorities.
Low-Volume to Production
Supports polished prototypes, custom geometries, and scalable molded optics when the design and glass grade are compatible.
Engineering Properties
Composition-Dependent Optical, Mechanical, and Thermal Characteristics
Chalcogenide glass is a material family rather than a single composition. Representative ranges below must be confirmed for the selected grade, wavelength, geometry, and operating environment.
Physical & Mechanical Properties
| Material Family | Glasses based on sulfur, selenium, or tellurium systems |
|---|---|
| Structure | Amorphous glass |
| Density | Approximately 3.0–5.0 g/cm³, composition dependent |
| Hardness | Lower than sapphire and many crystalline IR materials |
| Thermal Expansion | Grade dependent; include in athermal design analysis |
| Glass Transition | Composition dependent and relevant to molding and service temperature |
| Environmental Response | Grade-specific sensitivity to moisture, abrasion, and thermal cycling |
Optical Properties
| Transmission Range | Common grades span approximately 1–12 µm; selected grades extend farther |
|---|---|
| Refractive Index | Typically high, often approximately 2.2–3.5 in the infrared |
| Dispersion | Composition dependent; useful for IR achromatization |
| Visible Appearance | Usually dark and opaque in the visible spectrum |
| Reflection Loss | Significant when uncoated because of the high refractive index |
| Coating Compatibility | MWIR/LWIR AR, protective, filter, and custom spectral coatings |
| Available Grades | As-S, As-Se, Ge-As-Se, Ge-Sb-Se, and other engineered systems |
Types & Commercial Grades
Chalcogenide Glass Options for Infrared Optical Design
Material families and commercial grades can be evaluated according to spectral band, refractive index, dispersion, thermal behavior, environmental requirements, fabrication method, and availability.
Composition Families
Representative sulfur-, selenium-, and tellurium-based systems include As–S, As–Se, Ge–As–Se, and Ge–Sb–Se compositions.
SCHOTT IRG Series
Representative infrared chalcogenide glasses include IRG 22, IRG 24, IRG 25, IRG 26, and IRG 27.
AMTIR Series
Representative commercial materials include AMTIR-1, AMTIR-2, and AMTIR-8, with additional AMTIR grades available from the manufacturer.
BlackDiamond™ Series
Representative proprietary chalcogenide materials include BD2™ and BD6™ for molded or polished infrared optical components.
Availability notice. Brand names and trademarks belong to their respective manufacturers. Grade availability, substitutions, fabrication feasibility, and final specifications are confirmed for each project.
Optical Transmission
Infrared Coverage Tailored by Glass Composition
Transmission varies significantly across chalcogenide families. Material selection should begin with the operating band, absorption limits, temperature range, and required refractive-index behavior.
Representative envelope only. Final transmission depends on composition, thickness, surface finish, absorption bands, temperature, and coating.
Material Comparison
Where Chalcogenide Glass Adds Design Flexibility
| Property | Germanium | ZnSe | ZnS | Chalcogenide Glass |
|---|---|---|---|---|
| IR Coverage | Broad MWIR/LWIR | Broad VIS–LWIR | VIS–LWIR, grade dependent | Broad, composition dependent |
| Refractive Index | Very high | Moderate | Moderate | High and tailorable |
| Precision Molding | No | Limited | Limited | Strong advantage |
| Mechanical Durability | Good | Moderate | Good | Grade dependent |
| Best Fit | Thermal imaging | Broadband optics | Multispectral windows | Compact molded IR optics |
Manufacturing Capabilities
From Chalcogenide Glass Blank to Finished Infrared Component
COE Sapphire supports material selection, precision fabrication, optical finishing, coating, inspection, and integration for custom chalcogenide glass optics.
Precision Machining
Controlled cutting, edging, generating, beveling, and custom geometry fabrication with brittle-material handling.
Polishing & Molding
Precision polishing for prototypes and suitable aspheric or diffractive molding pathways for production designs.
Optical Coating
MWIR and LWIR anti-reflection, protective, filter, and custom spectral coating options.
Quality Assurance
Dimensional inspection, surface metrology, transmission verification, cosmetic inspection, and documentation.
Design Guide
Specify the Right Chalcogenide Glass Component
Provide operating wavelength and temperature, preferred glass grade, dimensions, tolerances, surface form and quality, clear aperture, edge treatment, coating, quantity, and environmental requirements.
Discuss Your SpecificationGlass GradeSelected by transmission, index, dispersion, and thermal behavior
Surface FormPlano, spherical, aspheric, diffractive, or custom
Production MethodPolished prototype or precision-molded production design
Mechanical DesignMounting and edge protection matched to glass properties
EnvironmentTemperature, humidity, abrasion, shock, and thermal cycling
CoatingsMWIR, LWIR, protective, filter, and custom coatings
Related Optical Components
Chalcogenide Glass Components Manufactured to Your Specification
Frequently Asked Questions
Chalcogenide Glass FAQs
What is chalcogenide glass?
Chalcogenide glass is an amorphous material containing one or more chalcogen elements such as sulfur, selenium, or tellurium, combined with network-forming elements to produce useful infrared optical properties.
What wavelength range does chalcogenide glass transmit?
The range depends on composition. Common infrared grades cover portions of approximately 1 to 12 µm, while selected compositions can extend beyond that range.
How does it compare with germanium?
Chalcogenide glass generally offers lower refractive index and less density than germanium, plus precision-molding potential. Germanium remains a strong choice for many established LWIR systems and harsh-environment designs.
Can chalcogenide glass be precision molded?
Yes. Compatible compositions can be molded into aspheric and diffractive surfaces, enabling compact designs and repeat production. Molding feasibility depends on geometry, tolerances, glass transition behavior, and volume.
Does chalcogenide glass require an AR coating?
Usually. Its relatively high refractive index creates significant surface reflection, so band-specific anti-reflection coatings are commonly used to improve system transmission.
Custom Chalcogenide Glass Optical Components
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