Influences of fluorescence film thickness and optical aberrations on curved surface metrology in fluorophore-aided scattering confocal microscopy

Fluorescence film thickness and optical aberrations are important systematic error sources of curved surface metrology in fluorescence-aided scattering confocal microscopy (FSCM). In this paper, we established a tilted surface measurement model in FSCM to analyse the influence of fluorescent film thickness and aberrations on the measurement accuracy under different local slope angles of a curved surface. The simulation results demonstrate that the systematic errors caused by the fluorescence film thickness on free-form surface measurements increase with the local slope angle of the surface. The systematic errors caused by optical aberrations will lead to significant deviations between the measured and the actual surface when the local slope angle is greater than the complementary angle of the half aperture angle of the objective lens. Our studies allow for analysing the systematic errors caused by fluorescence film thickness and optical aberrations in different situations, thus contributing to the uncertainty evaluation of free-form surface measurement by FSCM.