Infrared Material Selection by Wavelength

This plot compares the typical uncoated transmission (%) of common IR substrates versus wavelength (µm), helping you quickly shortlist materials that will pass your target band with minimal bulk absorption. Read it left‑to‑right by band: near‑IR (≈1–2.5 µm), mid‑IR (≈3–5 µm), and long‑IR/CO2‑laser region (≈8–12 µm), then focus on materials whose curves stay high and flat in your operating range. For example, CaF2 and BaF2 are useful into the mid‑IR before their long‑wavelength cutoffs, while ZnSe maintains strong transmission across much of the mid‑IR and into the CO2‑laser region. Ge and Si are primarily IR materials with strong transmission in specific IR windows, but their usable range and throughput depend strongly on thickness, surface finish, and any AR/DLC coatings applied. Use this chart as a first filter, then finalize by checking refractive index/dispersion, thermal properties, durability, and coating availability for your environment and power density.