Witness Samples

Witness Samples

Coating on different optical surfaces, including spherical, aspherical, planar, etc., but how to better detect the performance of thin film? The usual landscape photometer detection systems are suitable for plane detection, from which the witness samples are derived. Through the witness sample, the transmittance, reflectivity, actual applicable temperature, moderate and so on of the film can be detected.

Description of witness samples

The witness samples provided by ECOPTIK include a full range of brands such as CDGM, Schott, CORNING, etc. The general diameter is about 1'' and the thickness is 1-3mm, which basically adapts to the size of standard spectrophotometer tools.

ECOPTIK witness samples be polished one side or both surface according to the customers’ requirement to be used meet for transmit or reflect thin film coating

Specification of witness samples





Clear aperture

> 85% of diameter

Surface quality

60/40 or better


<3 arc min or better


λ/4 - λ/10@633nm


Fine ground


<0.2mm x 45deg

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