A simple fiber-optic sensor based on Fabry-Perot interference for refractive index measurement of optical glass is investigated both theoretically and experimentally. A broadband light source is coupled into an extrinsic fiber Fabry-Perot cavity formed by the surfaces of a sensing fiber end and the measured sample. The interference signals from the cavity are reflected back into the same fiber. The refractive index of the sample can be obtained by measuring the contrast of the interference fringes. The experimental data meet with the theoretical values very well. The proposed technique is a new method for glass refractive index measurement with a simple, solid, and compact structure.
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http://dx.doi.org/10.1364/AO.49.005592 | DOI Listing |
J Ophthalmol
January 2025
Optics and Optometry Department, Universidad Complutense de Madrid, Madrid, Spain.
To analyze the refractive accuracy of a novel swept-source optical coherence biometer (SS-OCT), that uses individual refractive indices to measure axial length, in short and long eyes implanted with monofocal intraocular lenses (IOLs). This retrospective comparative study considered eyes with short axial length (AL) (< 22.5 mm) or long AL (> 26 mm) bilaterally implanted with the Acrysof IQ monofocal IOL.
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January 2025
University of Warsaw, Krakowskie Przedmieście 26/28, 00-927, Warszawa, Poland.
Seismic profiling in a coal seam enables the determination of anomalous changes in the P-wave velocity compared to reference velocity at a specific mining depth, indicating potential stress changes. This information can improve the coal exploitation processes in advance at greater depths, especially in seismic hazard areas. This study aims to update the empirical mathematical formula for calculating reference P-wave velocities in coal seams by including new data measured at greater depths.
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January 2025
Department of Physics, Wolkite University, P. O. Box: 07, Wolkite, Ethiopia.
This study uses the Quantum ESPRESSO code to introduce Hubbard correction (U) to the density functional theory (DFT) in order to examine the effects of non-metals (C, F, N, and S) doping on the structural, electronic, and optical characteristics of rutile TiO. Rutile TiO is a substance that shows promise for use in renewable energy production, including fuels and solar energy, as well as environmental cleanup. Its wide bandgap, however, restricts their uses to areas with UV light.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
January 2025
GROW Research Laboratory, Narayana Netralaya Foundation, Bangalore, India.
Purpose: Keratoconus (KC) is characterized by irregular astigmatism along with corneal stromal weakness and is associated with altered immune status. Tissue resident microbiomes are known to influence the immune status in other organs, but such a nexus has not been described in ocular conditions. Therefore, we examined the ocular surface microbiome of patients with KC and correlated it to the immune cell and tear molecular factor profiles.
View Article and Find Full Text PDFCureus
December 2024
Cornea and Refractive Surgery, Al-Shifa Trust Eye Hospital, Rawalpindi, PAK.
Background: Glaucoma, particularly open-angle glaucoma (OAG), is a leading cause of irreversible blindness, associated with optic nerve damage, retinal ganglion cell death, and visual field defects. Corneal biomechanical properties and cellular components, such as corneal nerve and keratocyte densities assessed by in vivo confocal microscopy (IVCM), may serve as biomarkers for glaucoma progression. This study aimed to explore the relationship between corneal nerve parameters, keratocyte density, and optical coherence tomography (OCT)-derived retinal nerve fiber layer (RNFL) thickness in primary open-angle glaucoma (POAG) patients and controls.
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