The Variator is a panel of sliders for exploring how sensitive a design is. Drag any slider and the spectrum responds instantly: layer-thickness and substrate sliders nudge the shared design, so every open window — Optical Evaluation, Admittance, the electric-field and color tools — re-renders live, while the Variator’s own plot overlays the perturbed curve on a dotted baseline. It is a fast, reversible way to see which parameter matters before you commit to anything.
Settings
Section titled “Settings”Per-layer thickness — one slider per front and back layer, ranging roughly ±20 nm (or ±20 % of the layer, whichever is larger) around its baseline value. The slider label shows the layer’s material and baseline thickness.
Substrate thickness — nudges the substrate thickness in millimetres around its baseline.
Δn and Δk per material — one pair of sliders per unique material in the
stack, applied as constant offsets to the dispersive n(λ) and k(λ). These
stay local to the Variator preview — other windows keep showing the
unperturbed materials — and k is held at or above zero.
Preview controls — set the wavelength range and angle of incidence for the plot, toggle the dotted baseline overlay, and show the merit-function targets (when the design has any). The evaluation target (Front / Back / Total) is shown as a read-only badge and follows the Design Editor.
Revert — zeros every slider and restores the original design. Each slider row also has its own reset, and double-clicking a slider snaps it back to baseline.
How to read it
Section titled “How to read it”The solid R and T curves are the perturbed design; the dotted curves are the untouched baseline, so the gap between them is exactly the effect of the sliders you moved. The quickest use is a tolerance gut-check: jiggle one layer and watch a stopband edge walk — if a small move shifts the spectrum a lot, that layer needs tight process control.
Because the thickness and substrate sliders feed the shared design, the change is live everywhere, but it is non-destructive: the first slider move sets one undo checkpoint, so a single Ctrl+Z (or Revert) returns the design to where it started. The baseline is remembered while you re-arrange the workspace, so your reference point survives moving the window around.
References
Section titled “References”- H. A. Macleod, Thin-Film Optical Filters, 5th ed., §13.7 (sensitivity of multilayer performance to thickness errors).