Mirau-Based CSI with Oscillating Reference Mirror for Vibration Compensation in In-Process Applications

Abstract

We present a Mirau-type coherence scanning interferometer (CSI) with an oscillating reference mirror and an integrated interferometric distance sensor (IDS) sharing the optical path with the CSI. The IDS works simultaneously with the CSI and measures the distance changes during the depth scanning process with high temporal resolution. The additional information acquired by the IDS is used to correct the CSI data disturbed by unwanted distance changes due to environmental vibrations subsequent to the measurement. Due to the fixed reference mirror in commercial Mirau objectives, a Mirau attachment (MA) comprising an oscillating reference mirror is designed and built. Compared to our previous systems based on the Michelson and the Linnik interferometer, the MA represents a novel solution that completes the range of possible applications. Due to its advantages, the Mirau setup is the preferred and most frequently used interferometer type in industry. Therefore, the industrial use is ensured by this development. We investigate the functioning of the system and the capability of the vibration compensation by several measurements on various surface topographies.

A novel cubic‐exp evaluation algorithm considering non‐symmetrical axial response signals of confocal microscopes

“…The field of application of the cubic algorithm is not limited to depth response signals obtained by confocal microscopes. Asymmetrical signals or spectra to be evaluated also occur if other sensor principles such as coherence scanning interferometry (Lehmann & Xie, 2015;Serbes et al, 2021), optical coherence tomography (Fercher et al, 2002(Fercher et al, , 2003, chromatic confocal microscopy (Chen et al, 2019;Claus & Nizami, 2020) and focus variation microscopy (Cui et al, 2018;Xu et al, 2022)…”

“…The field of application of the cubic algorithm is not limited to depth response signals obtained by confocal microscopes. Asymmetrical signals or spectra to be evaluated also occur if other sensor principles such as coherence scanning interferometry (Lehmann & Xie, 2015; Serbes et al, 2021), optical coherence tomography (Fercher et al, 2002, 2003), chromatic confocal microscopy (Chen et al, 2019; Claus & Nizami, 2020) and focus variation microscopy (Cui et al, 2018; Xu et al, 2022) are being used. The cubic signal processing algorithm can be applied to increase the accuracy of the detection of the maximum position of a signal or spectrum compared to common approaches based on symmetrical approximations.…”

A novel cubic-exp evaluation algorithm considering non-symmetrical axial response signals of confocal microscopes

“…The field of application of the cubic algorithm is not limited to depth response signals obtained by confocal microscopes. Asymmetrical signals or spectra to be evaluated also occur if other sensor principles such as coherence scanning interferometry (Lehmann and Xie, 2015;Serbes et al, 2021), optical coherence tomography (Fercher et al, 2002(Fercher et al, , 2003, chromatic confocal microscopy (Chen et al, 2019;Claus and Nizami, 2020) and focus variation microscopy (Cui et al, 2018;Xu et al, 2022) are being used. The cubic signal processing algorithm can be applied to increase the accuracy of the detection of the maximum position of a signal or spectrum compared to common approaches based on symmetrical approximations.…”