Compensating aberration induced error in differential confocal microscopy

Johannes Belkner; Ingo Ortlepp; Uwe Gerhardt; Eberhard Manske

doi:10.1117/12.2592392

20 June 2021 Compensating aberration induced error in differential confocal microscopy

Johannes Belkner, Ingo Ortlepp, Uwe Gerhardt, Eberhard Manske

Proceedings Volume 11782, Optical Measurement Systems for Industrial Inspection XII; 117820P (2021) https://doi.org/10.1117/12.2592392
Event: SPIE Optical Metrology, 2021, Online Only

Abstract

Confocal microscopy is a working horse of optical profilometry since decades. It is a pointwise measurement method, where the whole sample must be scanned in all three dimensions. The high lateral resolution thereby outstrips its lowered scanning speed compared to widefield based principles. Furthermore, for a single 3D surface, even single-digit nanometre depth-resolution has been shown. However, albeit such high axial resolution, the accuracy may suffer from sample or optics induced wavefront distortions that differ from point to point. The acquired signal then experiences a shift that leads to a wrong acquired depth. Here we model this error through a low NA scalar model. We further present a method to compensate this error significantly by enhancing the principle of differential confocal microscopy. Theoretical results show the possibility for ideal compensation of the error caused by such in-stationary aberrations in confocal depth measurements.

Conference Presentation

Citation Download Citation

Johannes Belkner, Ingo Ortlepp, Uwe Gerhardt, and Eberhard Manske "Compensating aberration induced error in differential confocal microscopy", Proc. SPIE 11782, Optical Measurement Systems for Industrial Inspection XII, 117820P (20 June 2021); https://doi.org/10.1117/12.2592392

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