Influence of Scattering and Steepness in Optical Component Characterization Using Optical Coherence Tomography (OCT)

Optical Coherence Tomography (OCT) is increasingly used in industrial metrology, particularly in the production of optical components. This study investigates how surface steepness and roughness, in conjunction with scanning lens design, affect the accuracy and performance of OCT measurements. Three scanning lenses with different numerical apertures (NA) and fields of view were evaluated using two spectral-domain SD-OCT systems operating at 840 nm and 1300 nm, respectively, to image three distinct sample types. To complement the experiments, an optical simulation framework was developed to replicate each lens-sample configuration. Surface roughness for each sample was quantified using white-light interferometry and modeled via the K-correlation method, enabling realistic simulations of both specular reflections and scattered light components. Simulated reflection and scattering profiles were directly compared with experimental B-scans. The analysis revealed strong correlations between system configuration, surface characteristics, and measurement deviations. This integrated experimental-simulation approach provides practical insights for optimizing OCT system design in the inspection of complex optical geometries.