In our continuing effort to improve the qualification of thin film solutions to meet optical industry tasks, Omega has extended its capabilities in representing spectral data.
The performance of today's coatings in many cases exceeds the measurement capabilities of qualifying instruments. Spectrophotometer-based measurements using a reasonable spectral bandwidth (SBW) are limited by signal/noise to optical density (OD) levels of OD5 or OD6 at best. Although highly refined, these spectral analyzing devices cannot accurately represent both the precise wavelength and the intensity at that wavelength in a single measurement.
In contrast, laser-based measurements may be used to verify filter performance to much higher OD, proving filter response matches theoretical models. Laser-based rocking curves demonstrate that OD does not collapse, even in the higher order modes. Furthermore, perturbation experiments show that transmission always fails before OD fails (see Measuring Sharp Spectral Edges to High Optical Density).
To meet our customers' needs, Omega has developed dedicated measurement systems using specialized spectral analyzing equipment to overcome the limitations of current spectrophotometers. These systems intelligently combine spectral measurements with theoretical design predictions, thus increasing their capability. After carefully testing for validity, we are extending the dynamic range of our spectral representations to OD10, although performance beyond OD7 is subject to microscopic defects, such as voids, which are not quantified.
As these new measurement systems combine spectral measurement with advanced data analysis, in addition to extended spectral measurements we are also able to provide statistical performance data. These detailed descriptions of part-to-part variability may help with your instrument design and operational analysis. Initially, we can offer statistics around one of several of the spectral specifications such as CWL, HBW, peak %T, or average %T over a range.
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