This paper proposes an elegant technique for the simultaneous measurement of in-plane and out-of-plane displacements of a deformed object in digital holographic interferometry. The measurement relies on simultaneously illuminating the object from multiple directions and using a single reference beam to interfere with the scattered object beams on the CCD plane. Numerical reconstruction provides the complex object wave-fields or complex amplitudes corresponding to prior and postdeformation states of the object. These complex amplitudes are used to generate the complex reconstructed interference field whose real part constitutes a moiré interference fringe pattern. Moiré fringes encode information about multiple phases which are extracted by introducing a spatial carrier in one of the object beams and subsequently using a Fourier transform operation. The information about the in-plane and out-of-plane displacements is then ascertained from the estimated multiple phases using sensitivity vectors of the optical configuration.
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http://dx.doi.org/10.1364/AO.50.004189 | DOI Listing |
Sci Rep
January 2025
Faculty of Physics, Department of Optics and Optometry and Vision Sciences, Universitat de València, Burjassot, Spain.
A lensless compact arrangement based on digital in-line holography under Gabor's regime is proposed as a novel contactless method to assess the profile of multifocal intraocular lenses (MIOLs) which are conformed by several diffractive rings. Diffractive MIOLs are a widely adopted ophthalmologic option for the correction of presbyopia in patients undergoing cataract surgery. The MIOL optical design might introduce non-negligible optical performance differences between lenses as well as the introduction of undesirable photic phenomena (such as halos and glare) affecting the vision of users.
View Article and Find Full Text PDFACS Biomater Sci Eng
January 2025
Manipal Centre for Biotherapeutics Research, Manipal Academy of Higher Education, Manipal, 576104 Karnataka, India.
Volumetric additive manufacturing (VAM) is revolutionizing the field of cell printing by enabling the rapid creation of complex three-dimensional cellular structures that mimic natural tissues. This paper explores the advantages and limitations of various VAM techniques, such as holographic lithography, digital light processing, and volumetric projection, while addressing their suitability across diverse industrial applications. Despite the significant potential of VAM, challenges related to regulatory compliance and scalability persist, particularly in the context of bioprinted tissues.
View Article and Find Full Text PDFIn order to address the issue of low effective bandwidth ratio in off-axis digital holography, which is caused by the impact of zeroth- and first-order terms on the first-order term, an improved digital holographic reconstruction algorithm by zeroth-order term elimination based on the Riesz transform is proposed in this paper. First, an off-axis hologram is convolved with the Riesz kernels. Then, in the spectrum, the zeroth-order term is effectively eliminated by a singularity at the origin of the Riesz kernels, which can improve the effective bandwidth ratio and make the best use of the bandwidth.
View Article and Find Full Text PDFNanophotonics
December 2023
School of Physics and Astronomy, Faculty of Science, Monash University, Melbourne, Victoria 3800, Australia.
Nanophotonics
March 2024
Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong, China.
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