Open AccessTerahertz thickness determination with interferometric vibration correction for industrial applications
Author(s) -
Tobias Pfeiffer,
Stefan Weber,
Jens Klier,
S. Bachtler,
Daniel Molter,
Joachim Jonuscheit,
Georg von Freymann
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.012558
Subject(s) - terahertz radiation , optics , interferometry , materials science , metrology , vibration , terahertz spectroscopy and technology , distortion (music) , terahertz time domain spectroscopy , frequency domain , nondestructive testing , time domain , acoustics , optoelectronics , computer science , physics , amplifier , cmos , quantum mechanics , computer vision
In many industrial fields, like automotive and painting industry, the thickness of thin layers is a crucial parameter for quality control. Hence, the demand for thickness measurement techniques continuously grows. In particular, non-destructive and contact-free terahertz techniques access a wide range of thickness determination applications. However, terahertz time-domain spectroscopy based systems perform the measurement in a sampling manner, requiring fixed distances between measurement head and sample. In harsh industrial environments vibrations of sample and measurement head distort the time-base and decrease measurement accuracy. We present an interferometer-based vibration correction for terahertz time-domain measurements, able to reduce thickness distortion by one order of magnitude for vibrations with frequencies up to 100 Hz and amplitudes up to 100 µm. We further verify the experimental results by numerical calculations and find very good agreement.