The Broadband Monitoring Simulator is a 6-page wizard that simulates what happens when your design is actually deposited and watched by an in-chamber broadband spectrophotometer. It grows the coating layer by layer with realistic deposition-rate jitter, per-material index drift, and signal noise, lets the simulated monitor decide when to cut each layer, and then shows you the manufactured spectrum next to the theoretical one so you can see how well the design survives production.

You set up the deposition conditions on the first four pages, run a single computational-manufacturing experiment on page 5 and scrub through it like a movie, and read the resulting performance on page 6.

Settings

The wizard walks through one topic per page.

Page 1 — Deposition Rates. For each material, set the mean rate (nm/s), the RMS rate fluctuation, and the correlation time that controls how slowly the rate drifts. The preview shows a sample rate-vs-time trace; press Randomize to draw a new one.

Page 2 — Parameters Deviation. Per material, add a systematic and random shift to the real refractive index, plus a systematic inhomogeneity. The lower table lets you exclude individual layers from monitoring (they are then cut purely on time) and give each one an extra relative thickness error. Shutter delay (mean and RMS, in seconds) models the lag between the cut decision and the shutter actually closing.

Page 3 — Monitoring System. Choose the measured quantity and polarization (T or R, s/p/average), the angle of incidence, the scan interval between spectrum readings, and the monitoring band (λ min, λ max, and number of points). The preview shows the ideal monitoring signal for the layer selected in the tab strip.

Page 4 — Signal Errors. Add random noise (percent of signal) and a slow baseline drift to the monitor signal. The preview shows the noisy signal for the selected layer.

Page 5 — Deposition Simulation. Press Start to run one full manufacturing experiment. The coating then plays back layer by layer on an interactive timeline (play/pause, speed, scrub, layer ticks). The bar chart compares the estimated, actual, and target thickness of the current layer; the spectrum shows the theoretical guide curves (end, 80 %, 90 %) against the as-built curve.

Page 6 — Resulting Performance. Tabs show the manufactured vs. theoretical spectrum, relative and absolute thickness-error bars per layer, and tables of as-built thicknesses and refractive indices.

The coating side that is deposited, and the way the resulting spectrum is scored, follow the surface mode set in the Design Editor, shown as a badge on the window. The in-chamber monitor signal is always computed on a semi-infinite substrate, the way a spectrophotometer aimed through the chamber actually sees it.

How to read it

Page 6 is the verdict. If the manufactured curve hugs the theoretical one and the error bars are small, the design is robust to the monitoring conditions you set. Large thickness errors on a particular layer point to a layer that is hard to monitor at the chosen wavelength or strategy — a candidate for a different monitoring wavelength, tighter rate control, or a more tolerant redesign. Because every run uses fresh random draws, run it a few times (or re-run page 5) to see the spread of outcomes rather than trusting a single realization.

References

• Tikhonravov & Trubetskov, Appl. Opt. 44, 6877 (2005) — computational manufacturing as a bridge between design and production.
• H. A. Macleod, Thin-Film Optical Filters, 5th ed., Ch. 12.