Random-phase-shift Fizeau interferometer

Broistedt, Hagen; Doloca, Nicolae Radu; Strube, Sebastian; Tutsch, Rainer

doi:10.1364/ao.50.006564

Cited by 14 publications

(4 citation statements)

References 8 publications

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“…In order to avoid systematic errors, any amplitude modulation must be additionally reduced by the normalization of the measured signals. An approach concerning this normalization in a different context was already published [20]. Another critical aspect is the non-sinusoidal signal component which may result from multiple reflections between the measuring object and the probe head.…”

Section: Hilbert Transform Signal Processingmentioning

confidence: 99%

Measurement of distance changes using a fibre-coupled common-path interferometer with mechanical path length modulation

Schulz¹,

Lehmann²

2013

Meas. Sci. Technol.

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We present a novel type of fibre-coupled interferometric sensor. A micro-optical probe acts as a common-path interferometer and focuses the measuring light emitted by a laser diode onto the surface under investigation. The probe is mounted on a bending beam and deflected periodically by a piezoelectric actuator. This generates a phase-modulated interference signal, which is transformed to an electrical signal by a photo diode. The measurement principle is based on the fact that a distance change between the probe and the measurement object leads to a characteristic phase-shift of the measured signal. The photo diode signal is analysed in different ways in order to enable both high accuracy in the nanometre range and high measurement speeds, where the data rate of the sensor is finally limited by the conversion rate of the used analogue-to-digital converter. In order to extend the range of unambiguity of the sensor and to improve the robustness of measurement, we apply a dual-wavelength technique using two laser diodes emitting at different wavelengths simultaneously. Repeatability measurements, responses to distance changes and, finally, the measurement of calibration specimens with well-defined surface profiles demonstrate the performance of the system.

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Section: Hilbert Transform Signal Processingmentioning

confidence: 99%

Measurement of distance changes using a fibre-coupled common-path interferometer with mechanical path length modulation

Schulz¹,

Lehmann²

2013

Meas. Sci. Technol.

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“…In the phase shifting process, the OPD increment is very tiny, usually tens of nanometres, and therefore is easily disturbed by environmental unsteady factors. Due to the phase-shifting error caused by vibration, traditional phase extraction algorithms [1] are not suitable and researchers have developed many methods to minimise the effect of vibration on PSI, such as simultaneous phaseshifting method [2,3] and phase-shifting error detection and compensation method [4,5]. Both the two methods require modification of the interferometer and the configuration is elaborate.…”

Section: Introductionmentioning

confidence: 99%

Dual-mode phase-shifting interferometry based on iterative algorithms

Liu¹,

Huang²,

Yue

2019

Phys. Scr.

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Iterative algorithms are useful for retrieving wavefront phase from vibration disturbed interferograms for phase-shifting interferometry (PSI). But the dependence of convergence on the initial value deviation from the exact value impairs their application in severe vibration. In this paper, performance investigation of a representative iterative algorithm indicates that a higher frame rate of the camera, with matched phase shift, helps in enhancing the success probability of convergence. However, the camera frame rate is limited by its transmission speed and could not be increased easily. To improve the convergence of iterative algorithms, a dual-mode (DM) PSI is proposed that utilises the binning function of cameras. In DMPSI, two modes, high-speed and high-resolution modes, work consecutively by switching the camera binning function and two series of interferograms are collected respectively. The wavefront phase could be accurately estimated from high-speed interferograms and then is input to the iterative calculation with high-resolution interferograms as the initial value, and a wavefront phase with high-resolution is achieved ultimately. DMPSI combines the advantages of two complementary modes of cameras to reconstruct an accurate and high-resolution wavefront. Both simulations and a practical measurement verify the enhancement of vibration resistance of iterative algorithms. DMPSI is easy to implement with low cost and good compatibility, predicating a reliable solution for optical wavefront measurement in the severe vibration.

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“…Methods [1][2][3][4] were proposed to retrieve phase from interferograms with translational phase-shifting errors. Thereafter research was concentrated on relative tilt between reference and measured wavefronts, and some methods addressing it were proposed [5][6][7][8]. With tilt-shifting error compensated, the surface measurement error from phase-shifting error is well suppressed.…”

Section: Introductionmentioning

confidence: 99%

Vibration-resistant phase retrieval method with contrast compensation for phase-shifting interferometry

Liu¹,

He²,

Yuan³

et al. 2017

J. Opt.

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Vibration hinders the application of phase-shifting interferometry (PSI) to on-machine test and large-aperture mirror measurement. The investigation of PSI fringe disturbed by vibration indicates that, besides tilt-shifting error, inter- and intra-frame contrast variation is significant. The contrast variation is another dominant error source in phase retrieval of PSI. An inter- and intra-frame contrast compensation method is proposed here to retrieve wavefront phase from interferograms subjected to vibration. The method constructs algebraic equations with interferogram data and solves equations using iterative procedures. Experiments validate its effectiveness and manifest its capability to suppress vibration-induced error over a large frequency region. To enhance the calculation efficiency, a spatial subsampling strategy is proposed. Practical testing shows that subsampling reduces calculation time exponentially and preserves retrieval accuracy and spatial resolution. The proposed method, of which the unique ability is compensating the tilt-shifting error and fringe blur caused by vibration, predicates an effective and low-cost solution for PSI applied in vibration.

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Random-phase-shift Fizeau interferometer

Cited by 14 publications

References 8 publications

Measurement of distance changes using a fibre-coupled common-path interferometer with mechanical path length modulation

Measurement of distance changes using a fibre-coupled common-path interferometer with mechanical path length modulation

Dual-mode phase-shifting interferometry based on iterative algorithms

Vibration-resistant phase retrieval method with contrast compensation for phase-shifting interferometry

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