The Pros and Cons of Protected and Surface Coatings for High-Phase-Thickness Applications
Metal salt compounds, or dielectrics, produce thin-film coatings with precise spectral control. Because they are soft and require glass coverslips laminated to the coating substrate to protect them from damage, they are called protected coatings. Refractory metal-oxide materials, although hard and not in need of a protective glass layer, produce coatings that can demonstrate spectral shift over time, called durable surface coatings.
A jig with coated substrates is measured on an automated...
Photonics Spectra, July 2005