Use your own optical constants

Measured optical constants let you describe a film using supplied refractive-index data. In EUV Insight, attach that data to a layer, a material in a repeated group, or the substrate. Keep the sample identity and measurement conditions with the file so the result can be traced back to its inputs.

Prepare an optical-constants CSV

Use a header followed by 2–2,000 rows in a CSV or tab-separated file, no larger than 1 MB. Supply three distinct columns: wavelength or photon energy, and either n and k or δ and β. Column names can differ; you map them during import.

The app uses n + ik = 1 − δ + iβ, with nonnegative k or β. Check your source’s complex-index sign convention before importing. The importer does not infer or correct a different convention.

The file below is a practice dataset: 61 calculated Zr reference points from 12–15 nm at 6.52 g/cm³. It demonstrates the import format; it does not represent a new measurement.

wavelength_nm,n,k
12,0.96968324,0.00311206
13.5,0.95887617,0.00376529
15,0.94601334,0.00486249

Preview shows three selected rows, rounded for readability. Download the complete file for the exercise.

Import the file into your layer stack

1. Open the single-Zr example above. Confirm replacement if you already have a design open.
2. Set the workspace wavelength range to 12–15 nm and keep the target at 13.5 nm. Leave the 100 nm layer, disabled substrate, normal incidence and unpolarized illumination unchanged.
3. Open Materials and select the Zr layer under Material in this design.
4. Choose the downloaded file. Set Coordinate unit to nm and Optical convention to n, k. Map wavelength_nm, n and k to their corresponding columns.
5. Use a descriptive dataset name. In Source / citation, record “EUV Insight calculated Zr reference example; bundled CXRO data.” For a real dataset, enter its actual citation or instrument and sample details.
6. Select Use optical data. Inspect the imported and reference curves, then save the design if you want to retain the dataset with it.

Check coverage and interpolation

Imported values are interpolated linearly in wavelength. There is no extrapolation outside the supplied range. Ensure the table covers every wavelength needed by your spectrum, measurement comparison or optimization.

Energy coordinates are converted to wavelength and sorted. Duplicate coordinates, nonpositive n, and negative k are rejected. Use enough samples to resolve the features in your original data, especially near absorption edges.

At the supplied wavelengths, this practice file reproduces the reference optical constants up to numerical precision. Between those points, the imported and reference curves can differ because their interpolation procedures differ.

What happens to density and saved data?

Imported n and k are used directly. Changing the layer’s density does not rescale them, and density fitting is disabled for that material. Changing its chemical formula restores reference data. You can also select Restore reference data for this material in Materials.

The dataset, source and notes are embedded in the saved design; account sync includes that data when you save to your account. A separate reusable material library across designs is not yet available. Combined imported data is also subject to the saved-design size limit, so a valid individual file may still need fewer rows.

Use the imported data in a comparison

Once the material data is attached, the model uses it when predicting the optical response. Follow the measured-reflectivity comparison guide to inspect the difference between a supplied spectrum and a candidate stack. Document the material data as well as the fitted geometry.