We perform a detailed quantitative numerical analysis of a partially coherent quasi-cw fiber laser on the example of a high-Q normal dispersion cavity Raman fiber laser. The key role of precise spectral performances of fiber Bragg gratings forming the laser cavity is clarified. It is shown that cross-phase modulation between the pump and Stokes waves does not affect the generation. Amplitudes of different longitudinal modes strongly fluctuate, obeying the Gaussian distribution. As the intensity statistics is noticeably nonexponential, longitudinal modes should be correlated.
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http://dx.doi.org/10.1364/OL.35.003288 | DOI Listing |
J Neuroinflammation
January 2025
Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.
Background: The retinal degenerative diseases retinitis pigmentosa (RP) and atrophic age- related macular degeneration (AMD) are characterized by vision loss from photoreceptor (PR) degeneration. Unfortunately, current treatments for these diseases are limited at best. Genetic and other preclinical evidence suggest a relationship between retinal degeneration and inflammation.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
August 2024
In this paper, a new theoretical model of a partially coherent Laguerre-Gaussian (LG) beam carrying multiple off-axis vortex phases was established. The evolution properties of the focused intensity of the beam after passing through a thin lens were theoretically studied, and then the modulation effect of multiple off-axis vortex phases on the beam with multiring structured intensity was explored. The results indicate that the multiple off-axis vortex phases can reconstruct the multiring structured intensity within the LG beam, thus generating a structured intensity with multilobe and multiring patterns.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2025
Electrical and Computer Engineering, Duke University, Durham, North Carolina 27704, USA.
This paper addresses achieving the high time-bandwidth product necessary for low signal-to-noise ratio (SNR) target detection and localization in complex multipath environments. Time bandwidth product is often limited by dynamic environments and platform maneuvers. This paper introduces data-driven wideband focusing methods for passive sonar that optimize parameterized unitary matrices to align signal subspaces across the frequency band without relying on wave propagation models which are subject to mismatch in complex multipath environments.
View Article and Find Full Text PDFEye (Lond)
January 2025
Division of Clinical Neuroscience, Department of Ophthalmology, University of Nottingham, Nottingham, UK.
Background/objectives: Anterior segment optical Coherence Tomography (AS-OCT) is used extensively in imaging the cornea in health and disease. Our objective was to analyse and monitor corneal vascularisation (CVas) through the corresponding back-shadows visible on AS-OCT.
Subjects/methods: AS-OCT scans were obtained from 26 consecutive patients (eyes) with CVas of different aetiologies.
Medicine (Baltimore)
January 2025
Xi'an BRIGHT Eye Hospital Group Co Ltd. Xi'an, Shaanxi, China.
Rationale: Macular damage is a rare yet significant ocular complication of coronavirus disease 2019 (COVID-19) infection. This report highlights the clinical features, diagnosis, treatment, and outcomes in 2 cases of COVID-19-associated macular damage, contributing to the understanding of its pathophysiology and management.
Patient Concerns: Both patients presented with a sudden onset of visual impairment and black shadows in their central visual fields shortly after contracting COVID-19.
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