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The microfibril angle (MFA) giving the orientation of cellulose chains in hard sclerenchymatous bamboo fibers is one of the most important parameters determining the overall strength of the bamboo culm. In this work, Mueller matrix imaging polarimetry is implemented for determining MFA measured over a transverse section of group of fibers and parenchyma cells in bamboo of Dendrocalamus strictus species. The method, based on the Stokes-Mueller formalism, decouples the birefringence exhibited by crystalline cellulose from the clumped polarization parameters using 16 images taken with different polarization states at subcellular resolution. Retardance values, obtained from polar decomposition of the Mueller matrix, are extracted from different locations in the specimen, and distribution of MFA over the entire section is presented. The method permits simultaneous measurement of MFA in a transverse section of several fibers and parenchyma cells. The range of MFA obtained for bamboo fibers from Mueller matrix imaging is verified with the results obtained through x-ray diffraction using the pole figure method.
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http://dx.doi.org/10.1364/AO.55.008971 | DOI Listing |
Micromachines (Basel)
July 2025
Shanghai Precision Measurement Semiconductor Technology, Inc., Shanghai 210700, China.
As semiconductor manufacturing advances into the angstrom-scale era characterized by three-dimensional integration, conventional metrology technologies face fundamental limitations regarding accuracy, speed, and non-destructiveness. Although optical spectroscopy has emerged as a prominent research focus, its application in complex manufacturing scenarios continues to confront significant technical barriers. This review establishes three concrete objectives: To categorize AI-optical spectroscopy integration paradigms spanning forward surrogate modeling, inverse prediction, physics-informed neural networks (PINNs), and multi-level architectures; to benchmark their efficacy against critical industrial metrology challenges including tool-to-tool (T2T) matching and high-aspect-ratio (HAR) structure characterization; and to identify unresolved bottlenecks for guiding next-generation intelligent semiconductor metrology.
View Article and Find Full Text PDFJ Biomed Opt
August 2025
Leibniz University Hannover, Hannover Centre for Optical Technologies, Hannover, Germany.
Significance: Bacterial biofilm agglomerates are the cause of hard-to-treat implant-associated infections but currently can only be distinguished using sophisticated microbiological or molecular biological methods. Optical methods can potentially provide a label-free, noncontact approach to detect the presence of bacterial species associated with implant infections that could aid in the early diagnosis of implant-associated diseases.
Aim: Our aim is to measure the polarization signal from implant-associated bacteria biofilms using Mueller matrix polarimetry.
Rev Sci Instrum
August 2025
NanoLund and Solid State Physics, Lund University, S-22100 Lund, Sweden.
We report a Mueller matrix ellipsometer design using dual continuously rotating anisotropic meta wave plates, which determines the full set of Mueller matrix elements in the terahertz spectral range. The instrument operates in the frequency domain and employs a frequency tunable, solid state synthesizer based, continuous wave terahertz source with sub-MHz bandwidth. The implemented source permits operation within 82-125 and 170-250 GHz, without and with an additional frequency doubler, respectively.
View Article and Find Full Text PDFBackscattering Mueller matrix polarimetry has recently received wide attention in biomedical and clinical applications. However, during practical measurements, pixel saturation can inevitably arise from the specular reflection process, leading to inaccurate tissue information acquisition. In this Letter, we systematically analyze the influence of pixel saturation on backscattering Mueller matrix polarimetry.
View Article and Find Full Text PDFJ Periodontal Implant Sci
June 2025
Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
Purpose: The aim of this exploratory randomized controlled clinical trial was to compare profilometric and radiographic changes following early implant placement in sites treated with alveolar ridge preservation versus spontaneous healing (SH). Additionally, the study aimed to investigate clinical parameters of the implants up to 3 years following crown insertion.
Methods: Thirty-five patients exhibiting either intact buccal bone plates or buccal dehiscence of up to 50% after single-tooth extraction of incisors, canines, or premolars were enrolled.