Metallic coatings are essential for numerous optical systems due to
their high and broadband reflectivity in the infrared spectral range.
In contrast to well-established (protected) silver and gold mirror
coatings, iridium is environmentally durable, referring to ISO 9211-3
and thermally stable up to 600 °C even without protective
layers, as demonstrated. Additionally, the optical and related
structural properties of atomic layer deposited (ALD) and magnetron
sputtered (MS) Ir coatings were investigated using spectrophotometry,
FTIR, ellipsometry, WLI, AFM, XRR, XRD, SEM, and electrical
resistivity measurements. The properties of Ir ALD and Ir MS coatings
differ due to their topography and microstructure.