- How can I add refractive index file to the Catalog in Optilayer Pro? I have added several materials to the Layers Material database, but they don't show up in the Catalog.
OptiLayer/OptiChar/OptiRE Catalog databases were designed to be read-only. Typically we use already published data and provide corresponding references.
As a solution you can create a Problem Directory that will be used as an additional Catalog (MyCatalog, for example). You can place all your layer materials files there and use "File Transfer" option to take necessary files to your directories. Network shared locations are also supported.
In each new release, we extend data in the Catalog. If you think that your data deserves placing to Catalog and to be accessible by all OptiLayer customers, please, let us know. But in this case we will need to indicate all details related to the data.
- Can I use in OptiLayer layer materials which I created in OptiRe?
OptiLayer and OptiRE can use the same Problem Directories and can share the same data including materials and substrates. Designs also can be accessed through the Design database by both programs. Even material abbreviation assignment can be easily transferred from/to OptiLayer/OptiRE project files.
- I have a question related to Error analysis setup. I would like to understand how relative RMS errors are applied to the layers’ thicknesses. Let’s say: I specify 2% relative RMS errors for all thicknesses of a design. Could you explain what happens during the computations?
During Error analysis, variations of thicknesses are performed according to normally distributed random values. More specifically: Let the thickness of the layer is equal to . Then the RMS of 2% (for example) for this layer is determined as . The variation of this thickness is determined as , where is a normally distributed random value with average equal to m and RMS equal to (Variance ). See also http://en.wikipedia.org/wiki/Normal_distribution. For safety we also perform additional truncation of values outside the corridor of (they have quite low probability) in order to avoid too large rare variations. A similar procedure applies for absolute random errors, but in this case the variation is expressed absolute units.
- How can I properly calculate La*b* color values for transmission and reflectance? I evaluate La*b* color coordinates for a simple green glass substrate (Observer 2°, D65 light source) and OptiLayer gives a result that does not coincide which is not confirmed by a different software. D65 light source is chosen in the color checkbox (Color tab of General Configuration Window). If I additionally enter normalized D65 spectra as "Light Source", it works properly. I consider this as an inconvenience because I expect the program to calculate color values properly if I only check D65 in the checkbox!
In OptiLayer, it is not the case! Light Source that you select in Color tab (General Configuration Window) affects the position of the so-called Reference White point, that is used for the definition of some color spaces, including La*b*. Therefore, the role of this selection is just the definition of the Color space itself. Actual Light source can be different, and it is required by many applications. You load current Light Source (and optionally Detector) from the corresponding database. Of course, if you need to use D65 only, you need to specify this color source in two places: in Color tab of General Configuration window and load it to memory from the database. Maybe it requires an additional operation and more attention, but this approach provides more flexibility. Even more, using Environment Manager you are able to formulate and to solve problems with a set of different light sources for the same color space.
- I am working with monitoring spreadsheet (OptiMonitor) and observe that the Swing values do not coincide with the ones provided by Essential Macleod program. What is the reason?
Our definition of Swing is different from the one by Essential Macleod. In the case when no extrema is present inside the layer, we use "virtual" extremum concept, i.e., the extremum that may occur if we continue the deposition of this layer without interruption. On the other hand, Essential Macleod just uses ratios of initial and final values of the signal that is less informative from our point of view.
Small differences in the obtained values are most likely connected with the definition of the spectral line width or shape. It is obvious, that OptiLayer and Essential Macleod software perform numerical integration using different algorithms with a different number of nodes. In addition to this, "Half-Width parameter" in OptiLayer has a different meaning; it is not directly related to FWHM parameter. In the case of rectangular shape, it is straightforward that FWHM is half-width of this rectangle. In the case of Gaussian shape, it is A parameter in the formula defining spectral line profile, - the deviation of the wavelength from the central value: . It is easy to see that "Half width at half maximum" (HWHM) is connected with A with the formula: . These notes will help you to improve the correspondence of the results from OptiLayer and from Essential Macleod software.
Note, that in any case, the accuracy of measurements even in the most advanced in situ monitoring devices is lower that observed discrepancies.