The Specification window holds your design’s requirements as a list of PASS/FAIL qualifiers — “T ≥ 99 % averaged over 450–650 nm”, “R ≤ 0.5 % at 550 nm”, “no more than 30 layers”, and so on. It is the human-readable contract the coating must meet, kept separate from the Merit Function the optimizer minimizes. Each qualifier answers a yes/no question with a tolerance, and one button converts the whole list into merit operands so you can optimize toward exactly what you specified.

Each row is evaluated against the active design and recomputes on every change, showing a per-row verdict and an overall PASS/FAIL badge at the top.

Qualifier kinds

Kind	Asks	Units
T / R / A at λ	Channel value at a single wavelength versus a target.	%
T / R / A avg	Band-averaged channel value over a wavelength range.	%
Min / Max	Worst-case extremum of a channel over a band (catches spikes).	%
Integral	A source × detector weighted metric (e.g. T_vis, T_sol).	%
Central λ	Center wavelength of a passband or edge feature.	nm
FWHM	Full width at half-maximum of a feature.	nm
Edge λ	Wavelength where a channel crosses a level (a filter edge).	nm
Thickness budget	Total physical stack thickness.	nm
Layer count	Number of layers in the stack.	count

Settings

Each row exposes only the fields that apply to its kind:

Kind — one of the qualifier kinds above. Channel picks T, R or A (fixed for the at-a-wavelength and average kinds). λ / band is a single wavelength or a start/end range. AOI and pol set the angle of incidence and polarization for optical kinds.

Comparison and target — the actual test. You can require ≥, ≤, an equality = ± tol, or a range ∈ [lo, hi], against the target value you enter (percentages for T/R/A; nanometres or a count for the geometric kinds).

Presets — drop in a ready-made requirement set for a common coating type, either replacing or appending to the current list. You can also save the current list as your own reusable preset and load it back later.

How to read it

Each row carries a colored verdict: green and a check mark when it passes, red and a cross when it fails, with the measured value shown beside the target. The banner at the top turns green only when every active row passes, and reports how many of the total are passing. A failing row adds a short summary line explaining the miss.

For stopband suppression, prefer the Min / Max (worst-case) kinds: a band average can pass while a narrow resonance spikes through it. Once your requirements are in place, Generate MF writes them into the design as OPGT/OPLT merit operands — each spec becomes a measurement row plus a one-sided target referencing it — so Refinement and the synthesis tools optimize toward the specification directly and stay in sync with it. The specification is saved in the project file alongside the design.

References

• H. A. Macleod, Thin-Film Optical Filters, 5th ed., Ch. 7 (filter specifications: central wavelength, FWHM, edges).