Infrared materials are selected based on spectral transmission, refractive index, mechanical properties, and system-level requirements.
- Germanium (Ge): High refractive index (~4.0) with strong LWIR transmission (8–14 µm); suited for thermal imaging optics and IR sensing assemblies.
- Silicon (Si): Mechanically durable with good transmission in the 1–6 µm range; ideal for near-IR optics and harsh-environment applications.
- Zinc Selenide (ZnSe): Broad spectral transmission (~0.6–16 µm), low absorption; widely used in CO₂ laser optics and broadband IR systems.
- Zinc Sulfide (ZnS): Multispectral transmission (visible through LWIR, depending on grade); used in dual-/multi-band optical systems.
- Gallium Arsenide (GaAs): High refractive index semiconductor with IR transparency; applicable to advanced photonics, nonlinear optics, and quantum systems.