User-defined functions have been available as optimization targets since DESIGN 2.30.1000. 2.61.2200 added the ability to evaluate such functions. Both the FSPlot Module and Interactor are supported. A further improvement offers better utilization of the optional description field.

User-defined functions are accessed by clicking the User Defined button in either the Setup Parameters or Optimization Targets dialog. Variables are RFP (refl P), TRP (trns P), RFS (refl S), TRS (trns S), RPP (refl phase P), TPP (trns phase P), RPS (refl phase S), TPS (trns phase S). Reflectance and transmittance are in percent; phase is in degrees.

Note: File menu added in DESIGN 2.61.3950

New Jan 2017...User-defined functions are saved with Optimization Targets (FILM Archive) and may be cleared or changed upon opening a new FILM Archive. In order to utilize functions in multiple designs, DESIGN 2.61.3950 added a File menu enabling collections of functions (*.ufn) to be saved and recalled. Click a Test button to activate the Calculator and enter/test a formula. In addition, the Calculator Formula text box has been expanded to two lines (not shown below).

Syntax and other errors are indicated as shown below. After entering or editing a formula the Calculator offers the option of updating the corresponding row's Formula column.

Once defined, new functions appear in the Setup Parameters Plot list box as shown below.

The same functions appear in the Optimization Targets Type column and in the Generate Targets dialog.

In the seven layer design illustrated below, the goal was to achieve 20% TS/(TP+TS) in the range 450-600 nm at an angle of 45°. Note that polarization settings, such as those in the Pol column above, do not apply to user-defined functions.