We examine the influence of the refractive index core profile on the modal scattering of abruptly terminated slab waveguides. The analysis is based on the integral equation method with accelerating parameters, while for the field description in the waveguide core, an appropriate Lanczos-Fourier expansion is employed. The electric-field distribution on the terminal plane, the reflection and transformation coefficient of the TE guided modes, and the far-field radiation pattern are computed. Numerical results are presented for slab waveguides with step, linear, and parabolic refractive index profiles of the core. Finally, several approximate analytical solutions are derived to study the problem in question and to explain the results obtained.
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http://dx.doi.org/10.1364/josaa.24.001752 | DOI Listing |
Clin Exp Optom
January 2025
College of Optometry, University of Houston, Houston, TX USA.
Clinical Relevance: Hyperopia is a common refractive error in young children and has the potential to affect their visual, educational and general development. Management of childhood hyperopia presents significant intra-and inter-professional differences partly because evidence-based guidelines to inform when and how to prescribe for hyperopia are insufficient.
Purpose: This study investigated the prescribing philosophy in childhood hyperopia among optometrists in Ghana and the challenges faced in managing childhood hyperopia.
Atmospheric refraction imposes a fundamental limitation on the accuracy and precision of geodetic measurements that utilize electromagnetic waves. For terrestrial observations at optical wavelengths recorded over flat terrain, the vertical temperature gradient controls the bending of the rays thus affecting mostly the vertical angle measurement. The rules of thumb for mitigating these effects (variation ranges and short-term fluctuations) are based on intuition and practitioner experience.
View Article and Find Full Text PDFThe rigid Fabry-Pérot (F-P) cavity has emerged as the preferred core sensing component for optical pressure, vibration, and acoustic sensing in harsh environments, owing to its high reliability and structural stability. However, due to the inadequate temperature resistance of the optical dielectric film, maintaining a high level of precision in the rigid F-P cavity at elevated temperatures proves to be challenging. Volume Bragg grating (VBG) is a three-dimensional optical element modified by a femtosecond laser within a transparent glass medium to create a periodic refractive index distribution.
View Article and Find Full Text PDFAsia Pac J Ophthalmol (Phila)
January 2025
Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China. Electronic address:
Myopia stands as a prevalent ocular condition with global implications, impacting individuals at various life stages. In school-age children and adolescents, uncorrected myopia impedes reading and academic performance. Among middle-aged and elderly populations, myopia poses severe risks such as macular degeneration, macular holes and retinal detachment, leading to irreversible visual impairment.
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 PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!