Technical Issues - FilmStar News 2018

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January 2    Collector to Targets

DESIGN...Reverse-engineering can be more reliable when P/S measurements at angles > 0 are included. New multi-angle attachments (Cary UMA, PE Lambda with ARTA/TAMS) and the Spectra Collector enable users to save data in a single file. That capability has been enhanced with DESIGN  2.61.4150 able to quickly convert multi-angle spectra to Optimization Targets. (Previously this required opening multiple spectra and tediously converting one at a time or writing a macro utilizing BASIC Function SpecTargets.)

The procedure is as follows:

1. Open the DESIGN Collector (Spectra...Collector <Shift+F8>).

2. Open the Targets dialog (Optimize...Targets <Ctrl+T>). New targets supplement current ones, so you may need to clear the grid (File...Clear Targets <Shift+Del>) before clicking <Collector to Targets>.

Note that blue cells in the Collector grid indicate calculated data. Also note that Collector wavelength units (nm) were converted to current DESIGN units (Ám).

January 8    IndexSolve Updated with Collector

IndexSolve.bas was originally developed some years ago to partially automate (executable video file) a user's manual procedure for deducing n,k for silver through %R/%T measurements at multiple angles. The method is useful for metals of known thickness when it is impossible to utilize dispersive functions. The method depends on selecting a film thickness wherein both %R and %T can be accurately determined.

New IndexSolveCL.bas (CL for Collector) makes it much easier to load spectra. Users without MEASURE can duplicate Collector format in Excel by paying attention to row headers: TR = %T Random-pol, RP = %R P-pol, etc. Data can be placed in a single worksheet or in multiple sheets (tabs) with identical wave ranges. Click Spectra.. Sort to start with high wavelength.

DESIGN 2.61.4160 adds Function CLcell (Collector values) and CLinfo (row and column counts) (similar to Excel functions XLcell and XLinfo). Our example may be downloaded. Ag Setup.faw creates the Collection, while Ag Solve.faw deduces (n, k). If things work as expected (n, k) will match Ag_Sopra.itw values.

Blue cells indicate DESIGN-calculated test spectra

You need to run the calculation twice, for %T and %R. The values shown below were utilized.

Upon running this you obtain TP/TS and RP/RS 6░ columns. These were averaged (giving TR and RR) by highlighting adjacent 6░ columns and clicking Spectra.. Average P and S. If columns are not highlighted all P and S columns are averaged. In practice, data are generated by FilmStar MEASURE or by other programs via Excel transfer to Collector format.

As shown below, the solution (blue lines) overlaps original Sopra Ag.itw values (red lines)

Exercise for advanced users: Add noise to calculated spectra and see how it affects results.