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

摘要

We present detection of inhomogeneities in amorphous corundum layers by optical coherence tomography system withCMOS matrix detector. The presented setup is based on modified Twyman-Green interferometer with specially designedscanning module. The module consists of two beam directing mirrors, a beam splitter, an objective lens and it'silluminated by a high-power pig-tailed light emitting diode. The system is calibrated that the objective gives image ofzero optical path difference plane in infinity. Due to this and because the matrix detector is placed in the focal plane ofan 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 nodrop in transverse resolution coming from defocusing. In the paper we present, the idea of self-focusing tomographicsystem, its theoretical analysis and design aspects. Calibration of proposed system and its application for measurement ofamorphous corundum layers are also presented. The measurements results show occurrences of the inhomogeneities inthe investigated samples.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.