We show experimentally and theoretically that the use of optimized heterodyne detection in a diffusing-wave spectroscopy experiment leads to the detection of much smaller intensity autocorrelations than with conventional (either homodyne or heterodyne) setups. This enhanced resolution may be useful for the study of longtime dynamics of multiple-scattering disordered systems.
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http://dx.doi.org/10.1364/josaa.20.002179 | DOI Listing |
Carbohydr Polym
March 2025
Biophysics and Medical Technology, Department of Physics, NTNU Norwegian University of Science and Technology, Trondheim, Norway.
Schizophyllan (SPG) is a semi-flexible, triple-helical polysaccharide with attractive properties as an efficient viscosifying compound and biological response modifier. We report microrheological characterization of schizophyllan as dispersed in solution and the changes associated when crosslinked with chitosan over an extended frequency range using diffusing wave spectroscopy (DWS). A SPG with high molecular weight (M = 1.
View Article and Find Full Text PDFIt has been shown that light speckle fluctuations provide a means for noninvasive measurements of cerebral blood flow index (CBFi). While conventional Diffuse Correlation Spectroscopy (DCS) provides marginal brain sensitivity for CBFi in adult humans, new techniques have recently emerged to improve diffuse light throughput and thus, brain sensitivity. Here we further optimize one such approach, interferometric diffusing wave spectroscopy (iDWS), with respect to number of independent channels, camera duty cycle and full well capacity, incident power, noise and artifact mitigation, and data processing.
View Article and Find Full Text PDFACS Photonics
October 2024
Department of Precision and Microsystems Engineering, Delft University of Technology, Mekelweg 2, Delft 2628 CD, The Netherlands.
In measuring cerebral blood flow (CBF) noninvasively using optical techniques, diffusing-wave spectroscopy is often combined with near-infrared spectroscopy to obtain a reliable blood flow index. Measuring the blood flow index at a determined depth remains the ultimate goal. In this study, we present a simple approach using dual-comb lasers where we simultaneously measure the absorption coefficient (μ), the reduced scattering coefficient (μ ), and dynamic properties.
View Article and Find Full Text PDFPolymers (Basel)
September 2024
Departamento de Física Fundamental, Facultad de Ciencias, Universidad Nacional de Educación a Distancia (UNED), Paso Senda del Rey 9, 28040 Madrid, Spain.
This work investigated the gelation kinetics and mechanical properties of agarose hydrogels studied at different concentrations (in the range 1-5 g/L) and temperatures. Rheological measurements were performed by diffusing wave spectroscopy (DWS) using polystyrene and titanium dioxide particles as probes. The study emphasized the influence of gelation kinetics on the mechanical behavior of the hydrogels.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
Department of Mathematics, Physics and Computer Sciences, University of Parma, 43123 Parma, Italy. Electronic address:
Hypothesis: In order to understand the basic mechanisms affecting emulsion stability, the intrinsic dynamics of the drop population must be investigated. We hypothesize that transient ballistic motion can serve as a marker of interactions between drops. In 1G conditions, buoyancy-induced drop motion obscures these interactions.
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