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The total-field-scattered-field formulation of the finite-difference time-domain method (FDTD) is used to analyze the diffraction of finite incident beams by finite-number-of-periods holographic and surface-relief gratings. Both second-order and fourth-order FDTD formulations are used with various averaging schemes to treat permittivity discontinuities and a comparative study is made with alternative numerical methods. The diffraction efficiencies for gratings of several periods and various beam sizes, for both TE and TM polarization cases, are calculated and the FDTD results are compared with the finite-difference frequency-domain (FDFD) method results in the case of holographic gratings, and with the boundary element method results in the case of surface-relief gratings. Furthermore, the convergence of the FDTD results to the rigorous coupled-wave analysis results is investigated as the number of grating periods and the incident beam size increase.
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http://dx.doi.org/10.1364/ao.47.001981 | DOI Listing |
Soft Matter
August 2025
Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland.
Reproducing cell-cell and cell-extracellular matrix (ECM) interactions remains a challenge when developing new biomaterials. Especially, the dynamic nature of the ECM is often neglected when cells are cultured . Light-responsive materials are promising candidates to mimic the natural behavior of the ECM.
View Article and Find Full Text PDFSurface relief grating waveguides are widely used in augmented reality (AR) devices such as AR glasses. However, the rapid design and optimization of such waveguides remain challenging, particularly in large-scale devices such as augmented reality head-up displays. We propose a method for optimizing the brightness uniformity of waveguide exit pupils using deep neural networks.
View Article and Find Full Text PDFACS Appl Opt Mater
July 2025
The College of New Jersey, Department of Physics, 2000 Pennington Road, Ewing, New Jersey 08628, United States.
The photomechanical response of azobenzene-polymer films to polarized light is sufficiently strong to drive micron-scale surface relief formation. With a multitude of photonics applications, such optically written microstructures have motivated research to identify azopolymers and optical polarization technologies best matched to translate this phenomenon to practical devices. Here we present an overview of this field, with focus on a promising laser-writing platform based on structured polarized light projection from a high-resolution spatial light modulator.
View Article and Find Full Text PDFGels
May 2025
Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022 Valencia, Spain.
The creation of surface relief gratings using hydrogels for label-free biomolecule detection represents a significant advance in the development of versatile, cutting-edge biosensors. Central to this innovation is the formulation of materials with enhanced mechanical properties, especially for applications in soft, wearable technologies. In this work, we have developed novel biofunctional hydrogels that incorporate slide-ring supramolecular structures into their network, enabling the production of surface relief gratings with superior mechanical characteristics for biomolecule detection without the need for labels.
View Article and Find Full Text PDFJ Phys Chem B
June 2025
Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada.
A Nile blue (NB) chromophore functionalized with disperse red 1 (DR1) was synthesized in three steps. NB-DR1-guest host-poly(methyl methacrylate) films were deposited on glass substrates and used to produce rewritable surface relief gratings (SRGs). These SRGs were observed by fluorescence microscopy after exposition of the films to an interference pattern from a laser, revealing the fluorescence pattern that mapped the angle-dependent SRG.
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