Multispectral infrared material for MWIR and LWIR systems
Zinc Sulfide (ZnS) is a versatile infrared optical material transmitting from approximately 0.4 μm (visible edge) to 14 μm. Available in regular (transparent yellow) and Cleartran (multispectral) grades, it covers both MWIR and LWIR bands. ZnS offers good mechanical strength, moisture resistance, and is widely used for thermal imaging, FLIR systems, and airborne IR optics.
Zinc Sulfide is a polycrystalline infrared optical material produced by chemical vapor deposition (CVD). It offers broad transmission from the visible edge (~0.4 μm) through the LWIR (14 μm), making it one of the few materials suitable for multispectral applications.
Two main grades are available: regular ZnS (amber/yellow, better MWIR transmission) and Cleartran ZnS (water-white, optimized for multispectral 3–12 μm performance). Both offer excellent moisture resistance and good mechanical durability.
Reference data — verify with PhotonEdge for project-specific specifications.
Dual-band AR for MWIR and LWIR. Essential for multispectral systems.
Typical use: Multispectral thermal imaging
Single-band LWIR AR coating.
Typical use: Thermal imaging cameras
Hard protective overcoat for environmental durability.
Typical use: Outdoor/airborne systems
Regular ZnS for MWIR-optimized applications; Cleartran for multispectral or LWIR priority.
Softer than Ge (4 vs 6 Mohs). Handle with care; consider protective coatings for exposed surfaces.
Very low dn/dT (6×10⁻⁵/K) — excellent for athermal optical designs across temperature ranges.
CVD polycrystalline structure causes some scattering. Not suitable for high-precision imaging requiring minimal scatter.
ZnS covers broader range (MWIR+LWIR) but is softer. Ge is harder and has higher index for stronger optics.
ZnS has better multispectral performance; ZnSe has better transmission in specific bands and is preferred for CO₂ laser
ZnS covers IR; Sapphire covers UV-VIS-NIR. Different application domains.
Regular ZnS is amber-colored and optimized for MWIR. Cleartran is water-white with optimized multispectral performance from 3 to 12 μm.
Yes, ZnS transmits at 10.6 μm. However, ZnSe is often preferred for CO₂ laser due to lower absorption at that wavelength.
ZnS covers both MWIR and LWIR (broader range), while Ge is limited to 2-14 μm but is harder and has a higher refractive index.
ZnS has moderate hardness (4 Mohs). It is less scratch-resistant than Ge or Sapphire. Protective overcoats (DLC) are recommended for exposed surfaces.
Excellent. ZnS has very low dn/dT (6×10⁻⁵/K), making it nearly athermal — ideal for systems operating across wide temperature ranges.
Describe your application and wavelength requirements. Our engineering team will recommend the optimal material grade and specifications.
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