Rigorous modelling of scattered light from large area 3D surfaces for a confocal microscope using surface integral equation method

Confocal microscopy is a powerful optical instrument for fast and contactless surface profile measurement. With the advanced computation capability, it becomes increasingly desired to model the potential optical instruments for exploring beforehand the possible error source, uncertainties, and suitability for definite surfaces. Wave-optics simulations were have been developed to model confocal microscopes. However, the scattering from biological or technical surfaces was normally approached by a thin phase layer, which cannot predict multi-scattering and polarization effects. We report modelling results from large area surfaces for a confocal microscope using a rigorous simulation tool based on surface integral equation method and multi-level fast multiple algorithm, with which polarization effects, multiple-scattering effects are included. The results will be compared with those from other method scattering models such as thin layer approximation and rigorous coupled wave analysis method.