Witness Samples are essential to maintaining accuracy, repeatability and traceability of any thin film coating operation. Witness Samples aid in the measurement of transmission and reflectivity performance. They are also used to measure the durability of a coating and verify the resistance to environmental effects like humidity, temperature, salt spray, etc.

Esco offers a full complement of witness samples in three different configurations: Transmission, Reflection and Wedged. Most common generic indices as well as specific optical glass manufacturer's types are available. We can also supply melt specific materials at a competitive cost to our customers. Please note that specific optical glass and material pricing fluctuates, and may be subject to change.

Transmission: Polished 2 sides | Reflection: Polished 1 side/opposite ground finish | IR materials: Polished 2 sides
Diameter 25.40 mm +/-0.10 | Thickness 1.50 mm +/-0.25 | Flatness <1.0 wave @633nm | Surface Quality 60-40 scratch-dig