Phase-shifting interferometry (PSI) is the preferred non-contact method for profiling sub-nanometer surfaces. Based on monochromatic light interference, the method computes the surface profile from a set of interferograms collected at separate stepping positions. Errors in the estimated profile are introduced when these positions are not located correctly. In order to cope with this problem, various algorithms that minimize the effects of certain types of stepping errors (linear, sinusoidal, etc.) have been developed. Despite the relatively large number of algorithms suggested in the literature, there is no unified way of characterizing their performance when additional unaccounted random errors are present. Here, we suggest a procedure for quantifying the expected behavior of each algorithm in the presence of independent and identically distributed (i.i.d.) random stepping errors, which can occur in addition to the systematic errors for which the algorithm has been designed. The usefulness of this method derives from the fact that it can guide the selection of the best algorithm for specific measurement situations.
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http://dx.doi.org/10.1364/AO.55.008925 | DOI Listing |
Sci Rep
January 2025
School of Opto-electronics Engineering, Xi'an Technological University, Xi'an, 710021, China.
This paper explores a multi-directional (multiple directional) shearing synchronous polarization phase-shifting interferometer that utilizes a birefringent crystal displacer. This design effectively mitigates nonlinear issues and environmental influences commonly encountered in synchronous phase-shifting interferometry. Additionally, it enables the acquisition of shear wavefront information from multiple directions.
View Article and Find Full Text PDFRev Sci Instrum
December 2024
OFS Laboratories, 19 Schoolhouse Road, Somerset, New Jersey 08873, USA.
Transmission matrix measurements of multimode fibers are now routinely performed in numerous laboratories, enabling control of the electric field at the distal end of the fiber and paving the way for the potential application to ultrathin medical endoscopes with high resolution. The same concepts are applicable to other areas, such as space division multiplexing, targeted power delivery, fiber laser performance, and the general study of the mode coupling properties of the fiber. However, the process of building an experimental setup and developing the supporting code to measure the fiber's transmission matrix remains challenging and time consuming, with full details on experimental design, data collection, and supporting algorithms spread over multiple papers or lacking in detail.
View Article and Find Full Text PDFPrecise dynamic single-frame interferometry based on virtual phase shifting technique remains challenging due to the difficulty in satisfying the requirements for the quality and amount of fine-grained fringe's interferograms. Here we introduce a novel deep learning architecture, the Transformer Encoder-Convolution Decoder Phase Shift Network (TECD-PSNet), that achieves high-fidelity interferogram reconstruction. TECD-PSNet seamlessly integrates the strengths of transformer blocks in capturing global descriptions and convolution blocks in efficient feature extraction.
View Article and Find Full Text PDFIn this study, we present lateral scanning white light interferometry (LS-WLI), where phase-shifting algorithms are applied to inspect the topography of a large field of view (FOV) with high-speed measurements. At a point, the interference signal must be acquired with a specific condition to adapt the phase-shifting algorithm. This means that all points have two points, of which the phase difference is π/2, when the number of points acquired in a phase period is multiple of 4, despite increasing the data points in a period.
View Article and Find Full Text PDFLight Sci Appl
October 2024
Institut Fresnel, CNRS, Aix Marseille Univ, Centrale Med, Marseille, France.
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