Measurement of amorphous corundum layers by self-focusing optical coherence tomography system with matrix detector

Slawomir Tomczewski; Leszek Salbut

doi:10.1117/12.929278

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13 September 2012 Measurement of amorphous corundum layers by self-focusing optical coherence tomography system with matrix detector

Slawomir Tomczewski, Leszek Salbut

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Proceedings Volume 8494, Interferometry XVI: Applications; 84940M (2012) https://doi.org/10.1117/12.929278
Event: SPIE Optical Engineering + Applications, 2012, San Diego, California, United States

Abstract

We present detection of inhomogeneities in amorphous corundum layers by optical coherence tomography system with CMOS matrix detector. The presented setup is based on modified Twyman-Green interferometer with specially designed scanning module. The module consists of two beam directing mirrors, a beam splitter, an objective lens and it's illuminated by a high-power pig-tailed light emitting diode. The system is calibrated that the objective gives image of zero optical path difference plane in infinity. Due to this and because the matrix detector is placed in the focal plane of an imaging lens, therefore even if distance between the objective and the imaging lens changes during scanning process, the zero optical path difference plane is always in-focus. Hence the system focuses itself on imaged layers and there is no drop in transverse resolution coming from defocusing. In the paper we present, the idea of self-focusing tomographic system, its theoretical analysis and design aspects. Calibration of proposed system and its application for measurement of amorphous corundum layers are also presented. The measurements results show occurrences of the inhomogeneities in the investigated samples.

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Slawomir Tomczewski and Leszek Salbut "Measurement of amorphous corundum layers by self-focusing optical coherence tomography system with matrix detector", Proc. SPIE 8494, Interferometry XVI: Applications, 84940M (13 September 2012); https://doi.org/10.1117/12.929278

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