General Introduction

The refractive-index fitting module fits material refractive index using photometric data.

Fitting usually requires one or more of: transmittance, reflectance, and film thickness measurements. Given equivalent data accuracy, having more data types improves fitting reliability.

The module supports fitting for substrates or coating materials. When fitting coating materials, the substrate refractive index is typically required (it can be fitted first).

Multi-angle photometric data often helps convergence.

Scope

This fitting module is intended for single-layer coating materials. For substrates or optically thick transparent layers (k ≈ 0) use the Filmstar Index module; consult the Filmstar documentation for details.

Fitting Flow

A typical refractive-index fitting workflow is shown below: