Radiation dose measurements based on scintillator detection are conveniently made by coupling the light from the scintillator into an optical fiber. The low light levels involved typically require sensitive photodetectors, so it is advantageous to increase the available signal by optimizing the optical coupling efficiency between the scintillator and optical fiber. We model this process using geometric optics and finite-element ray tracing to determine the features that maximize the amount of light coupled to an optical fiber from a cylindrical scintillator. We also address whether the coupling can be improved by using an intermediate optical element such as a lens, and we provide a means for calculating its required optical properties for a given geometry.
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http://dx.doi.org/10.1364/ao.46.000397 | DOI Listing |
Photodiagnosis Photodyn Ther
January 2025
Department of Ophthalmology, Ankara Bilkent City Hospital, University of Health Sciences, Ankara, Turkey.
Purpose: In this study, it was planned to compare the macular ganglion cell analysis (GCA) and peripapillary retinal nerve fiber layer (pRNFL) of the patients with preperimetric glaucoma (PPG), early stage glaucoma (EG) and the control group.
Methods: This retrospective study included a total of 103 eyes: 38 from EG patients, 30 from PPG patients, and 35 from healthy individuals at Ankara Bilkent City Hospital Glaucoma Unit between January 2018 and September 2021. Eyes were categorized into control, PPG, and EG groups based on visual field (VF) classification.
J Colloid Interface Sci
January 2025
State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 PR China. Electronic address:
Luminescent solar concentrators (LSCs) are large scale sunlight collector and can be used for building-integrated photovoltaics (BIPV). Achieving high-performance LSCs requires fluorophores with broad absorption, high quantum yield and a large Stokes shift. Nevertheless, conventional high-efficiency LSCs typically rely on heavy metal-based quantum dots as fluorophores.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
Department of Physics, Washington State University, Pullman, WA 99163, USA.
This work aims to determine the mechanism of the photomechanical response of poly(Methyl methacrylate) polymer doped with the photo-isomerizable dye Disperse Red 1 using the non-isomerizable dye Disperse Orange 11 as a control to isolate photoisomerization. Samples are free-standing thin films with thickness that is small compared with the optical skin depth to assure uniform illumination and photomechanical response throughout their volume, which differentiates these studies from most others. Polarization-dependent measurements of the photomechanical stress response are used to deconvolute the contributions of angular hole burning, molecular reorientation and photothermal heating.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Department of Communications Engineering, University of the Basque Country, 48013 Bilbao, Spain.
Optical Fiber Displacement Sensors (OFDSs) provide several advantages over conventional sensors, including their compact size, flexibility, and immunity to electromagnetic interference. These features make OFDSs ideal for use in confined spaces, such as turbines, where direct laser access is impossible. A critical aspect of OFDS performance is the geometry of the fiber bundle, which influences key parameters such as sensitivity, range, and dead zones.
View Article and Find Full Text PDFSensors (Basel)
January 2025
School of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510006, China.
Refractive index (RI) and temperature (T) are both critical environmental parameters for environmental monitoring, food production, and medical testing. The paper develops a D-shaped photonic crystal fiber (PCF) sensor to measure RI and T simultaneously. Its cross-sectional structure encompasses a hexagonal-hole lattice, with one hole selectively filled with toluene for temperature sensing.
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