Karhunen-Loève functions represent the best choice for modal wavefront reconstruction. They are usually built up as a linear combination of Zernike polynomials by using principal component analysis methods; thus they are ordered by covariance. Using Shannon information theory, we provide a best reordering procedure based on the concept of mutual information. This enhances reconstruction efficiency, allowing us to reduce the basis dimension while maintaining the same fitting error in wavefront reconstruction.
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http://dx.doi.org/10.1364/AO.49.002090 | DOI Listing |
Sensors (Basel)
January 2025
Huawei Technologies Co., Ltd., Chengdu 610000, China.
Metasurface-based imaging is attractive due to its low hardware costs and system complexity. However, most of the current metasurface-based imaging systems require stochastic wavefront modulation, complex computational post-processing, and are restricted to 2D imaging. To overcome these limitations, we propose a scanning virtual aperture imaging system.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal and INESC TEC, Centre of Applied Photonics, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
Easily accessible through tabletop experiments, paraxial fluids of light are emerging as promising platforms for the simulation and exploration of quantumlike phenomena. In particular, the analogy builds on a formal equivalence between the governing model for a Bose-Einstein condensate under the mean-field approximation and the model of laser propagation inside nonlinear optical media under the paraxial approximation. Yet, the fact that the role of time is played by the propagation distance in the analog system imposes strong bounds on the range of accessible phenomena due to the limited length of the nonlinear medium.
View Article and Find Full Text PDFInt J Comput Assist Radiol Surg
December 2024
High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801, Japan.
Purpose: In this paper, we describe an algebraic reconstruction algorithm with a total variation regularization (ART + TV) based on the Superimposed Wavefront Imaging of Diffraction-enhanced X-rays (SWIDeX) method to effectively reduce the number of projections required for differential phase-contrast CT reconstruction.
Methods: SWIDeX is a technique that uses a Laue-case Si analyzer with closely spaced scintillator to generate second derivative phase-contrast images with high contrast of a subject. When the projections obtained by this technique are reconstructed, a Laplacian phase-contrast tomographic image with higher sparsity than the original physical distribution of the subject can be obtained.
Sensors (Basel)
December 2024
School of Opto-Electronics Engineering, Xi'an Technological University, Xi'an 710021, China.
To overcome the limitations of phase sampling points in testing aspherical surface wavefronts using traditional interferometers, we propose a high-spatial-resolution method based on multi-directional orthogonal lateral shearing interferometry. In this study, we provide a detailed description of the methodology, which includes the theoretical foundations and experimental setup, along with the results from simulations and experiments. By establishing a relational model between the multi-directional differential wavefront and differential Zernike polynomials, we demonstrate high-spatial-resolution wavefront reconstruction using multi-directional orthogonal lateral shearing interferometry.
View Article and Find Full Text PDFThe Shack-Hartmann wavefront sensor (SHWS) is known for its high accuracy and robust wavefront sensing capabilities. However, conventional compact SHWS confronts limitations in measuring field-of-view to meet emerging applications' increasing demands. Here, we propose a high-density lens transfer function retrieval (HDLTR)-based SHWS to expand its field-of-view.
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