Usable from 5.6µm. See attached image for spectral performance curve

Specifications:

Material: Zinc Selenide (ZnSe)
Laser Grade Diameter Tolerances: +.000”, -.005” for parts up to 2.000”Ø
+.000”, -.010” for parts from 2.50” to 6.000”Ø
Thickness: ±.010”
Parallelism: < 30 seconds of arc
Surface Quality: < 40/20 scratch – dig Laser Finish

Spectral Performance:

Standard AR Coating type both sides @5.5µm
Absorption: < 0.3 % total
Reflectance: < 0.50% per surface @ 5.5µm
Transmittance: > 98.5% typical