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Comparing fundus autofluorescence and infrared imaging findings of peripheral retinoschisis, schisis detachment, and retinal detachment
摘要： Purpose: The primary goal of this study was to identify characteristic features of peripheral degenerative retinoschisis (RS), schisis detachment (SD) and retinal detachment (RD) on both fundus autofluorescence (FAF) and infrared (IR) imaging, using spectral domain optical coherence tomography (SD-OCT) imaging of the peripheral retina as the confirmatory imaging tool. Methods: This is a descriptive case series study. A total of 27 eyes of 22 patients were included. Thirteen eyes of 10 patients diagnosed with RS, 4 eyes of 3 patients diagnosed with SD, and 10 eyes of 9 patients diagnosed with RD were included. Patients with images of poor quality were excluded. Heidelberg Spectralis HRA + OCT machine (Heidelberg Engineering, Heidelberg, Germany) were used to acquire the images. Results: All conditions appeared as areas of hypo-AF on FAF and hypo-reflectance on IR imaging. Accentuated vasculature of the lesion was noted with IR imaging due to elevation of the RS and RD, which was less frequently observed with FAF. On FAF, a hyper-AF leading edge around the RS lesion indicated the presence of intraretinal or subretinal fluid and an extension of the RS. Retinal breaks/holes were best visualized with IR imaging. SD-OCT confirmed the diagnosis in all performed cases. Conclusions: We were unable to differentiate between RS and RD based solely on findings from FAF and IR imaging. However, the combination of them with SD-OCT can assist in the diagnosis of RS from RD and in the evaluation of RS progression. OCT remains the main modality imaging to differentiate these conditions.
关键词： Retinoschisis,Retinal detachment,Fundus autofluorescence,Infrared imaging,Spectral domain optical coherence tomography,Schisis detachment
更新于2025-09-23 15:21:01
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[Lecture Notes in Computer Science] Pattern Recognition and Computer Vision Volume 11256 (First Chinese Conference, PRCV 2018, Guangzhou, China, November 23-26, 2018, Proceedings, Part I) || Automated and Robust Geographic Atrophy Segmentation for Time Series SD-OCT Images
摘要： Geographic atrophy (GA), mainly characterized by atrophy of the retinal pigment epithelium (RPE), is an advanced form of age-related macular degeneration (AMD) which will lead to vision loss. Automated and robust GA segmentation in three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) images is still an enormous challenge. This paper presents an automated and robust GA segmentation method based on object tracking strategy for time series SD-OCT volumetric images. Considering the sheer volume of data, it is unrealistic for experts to segment GA lesion region manually. However, in our proposed scenario, experts only need to manually calibrate GA lesion area for the ?rst moment of each patient, and then the GA of the following moments will be automatically detected. In order to fully embody the outstanding features of GA, a new sample construction method is proposed for more e?ectively extracting histogram of oriented gradient (HOG) features to generate random forest models. The experiments on SD-OCT cubes from 10 eyes in 7 patients with GA demonstrate that our results have a high correlation with the manual segmentations. The average of correlation coe?cients and overlap ratio for GA projection area are 0.9881 and 82.62%, respectively.
关键词： HOG features,Spectral-domain optical coherence tomography,Image segmentation,Geographic atrophy
更新于2025-09-23 15:21:01
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LED Structures Based on ZnO Films Obtained by RF Magnetron Sputtering for the UV Spectral Range
摘要： Data for the influence of different defects on the photoluminescence and electroluminescence spectra (emission intensity and wavelength) of n-ZnO/p-GaN structures are reported.
关键词： ZnO films,photoluminescence,RF magnetron sputtering,UV spectral range,electroluminescence
更新于2025-09-23 15:21:01
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Multicolor Persistent Luminescence Realized by Persistent Color Conversion
摘要： Spectral tuning is important for the development of persistent phosphors. Here we introduce a color conversion concept to obtain abundant persistent luminescence spectra in addition to existing methods of exploring new matrix and/or dopants. In this study, CaAl2O4:Eu,Nd was chosen as a blue persistent donor phosphor, while Lu3Al5O12:Ce and other four commercial phosphors were explored as conversion phosphors to obtain colorful persistent luminescence spectra. Both the persistent donor phosphor and conversion phosphors were embedded into resin, forming ternary composite chips to ensure efficient energy transfer. Continuous color tuning were realized by simply changing the mass ratio of the persistent donor phosphor vs. conversion phosphor. Our work will be significant in indicating other persistent/conversion composite materials or nanostructures with abundant spectral properties.
关键词： composite,Persistent luminescence,afterglow,persistent phosphor,spectral tuning
更新于2025-09-23 15:21:01
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New hybrid metaheuristic algorithm for scintillator gamma ray spectrum analysis
摘要： The Sodium Iodide detector (NaI(Tl)) is one of the most widely used nuclear devices in gamma-ray spectrometry due to its high efficiency and low price. However, this detector has low energy resolution and spectra measured by this detector are associated with Gaussian broadening. Therefore, the detector cannot resolve the photopeaks with very close energies. To overcome this problem, spectral deconvolution methods such as boosted ML-EM and boosted Gold algorithms have been proposed, that somewhat resolve the complex spectrum. But these methods cannot obtain a spectrum consisting of narrow photopeaks. Therefore, due to the importance of spectral deconvolution and its applications, there is always a need for a more efficient and precise method. In this study, a new multi-step method based on metaheuristic algorithms is introduced for deconvolution of NaI(Tl) detector spectrum. The new method is used for deconvolution of measured and simulated complex spectra and results are compared with the results of previous methods. The results show that the new multi-step spectral deconvolution method has a very high accuracy and efficiency in deconvolution of the complex spectra.
关键词： Metaheuristic algorithms,Multi-step method,Spectral deconvolution,NaI(T1) detector
更新于2025-09-23 15:21:01
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Ring-shaped optical coherence lattice distribution produced by light waves on scattering
摘要： With the help of Markov approximation, a layer-structured random medium which may produce a far-zone scattered field with ring-shaped optical coherence lattice (RSOCL) distributions is discussed, and properties of the RSOCL produced by such a medium are investigated. It is shown from the distribution of the RSOCL that the diameter of each Gaussian profile lobe, the radial distance of all adjacent lobes, the number of the rings, the number of the lobe of each ring, and the radial distance of the array rings can be properly controlled by adjusting structural parameters of the scattering medium. Furthermore, by a method of superposition of several non-negative weight functions, a RSOCL with tunable lobes intensity distribution was obtained.
关键词： Light wave scattering,light field manipulating,spectral density
更新于2025-09-23 15:21:01
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Infrared spectroscopy of live cells from a flowing solution using electrically-biased plasmonic metasurfaces
摘要： Spectral cytopathology (SCP) is a promising label-free technique for diagnosing diseases and monitoring therapeutic outcomes using FTIR spectroscopy. In most cases, cells must be immobilized on a substrate prior to spectroscopic interrogation. This creates significant limitations for high throughput phenotypic whole-cell analysis, especially for the non-adherent cells. Here we demonstrate how metasurface-enhanced infrared reflection spectroscopy (MEIRS) can be applied to a continuous flow of live cell solution by applying AC voltage to metallic metasurfaces. By integrating metasurfaces with microfluidic delivery channels and attracting the cells to the metasurface via dielectrophoretic (DEP) force, we collect the infrared spectra of cells in real time within a minute, and correlate the spectra with simultaneously acquired images of the attracted cells. The resulting DEP-MEIRS technique paves the way for rapid SCP of complex cell-containing body fluids with low cell concentrations, and for the development of a wide range of label-free liquid biopsies.
关键词： dielectrophoretic force,live cells,FTIR spectroscopy,microfluidic delivery channels,Spectral cytopathology,metasurface-enhanced infrared reflection spectroscopy,label-free liquid biopsies
更新于2025-09-23 15:21:01
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Challenges and opportunities for nanomaterials in spectral splitting for high-performance hybrid solar photovoltaic-thermal applications: A review
摘要： Hybrid photovoltaic-thermal (PV-T) collectors, which are capable of cogenerating useful thermal energy and electricity from the same aperture area, have a significantly higher overall efficiency and ability to displace emissions compared to independent, separate photovoltaic panels, solar thermal collectors or combinations thereof. Spectral splitting has emerged as a promising route towards next-generation high-performance PV-T collectors, and nanotechnology plays an important role in meeting the optical and thermal requirements of advanced spectral splitting PV-T collector designs. This paper presents a comprehensive review of spectral splitting technologies based on nanomaterials for PV-T applications. Emerging nanomaterials (nanofluids, nanofilms and nanowires) suitable for achieving spectral splitting based on reflection, diffraction, refraction and/or absorption approaches in PV-T collectors are presented, along with the associated challenges and opportunities of these design approaches. The requirements from such materials in terms of optical properties, thermal properties, stability and cost are discussed with the aim of guiding future research and innovation, and developing this technology towards practical application. Nanofluids and nanofilms are currently the most common nanomaterials used for spectral splitting, with significant progress made in recent years in the development of these materials. Nevertheless, there still remains a considerable gap between the optical properties of currently-available filters and the desired properties of ideal filters. Aiming to instruct and guide the future development of filter materials, a simple generalized method is further proposed in this paper to identify optimal filters and efficiency limits of spectral splitting PV-T systems for different scenarios. It is found that the optimal filter of a spectral splitting PV-T system is highly sensitive to the value of thermal energy relative to that of electricity, which therefore depends strongly on the application and location. The efficiency limit of spectral splitting PV-T collectors is significantly higher than that of standalone PV panels. The stability of nanomaterial filters remains a critical challenge for their long-term employment and also for high-temperature operation in practical applications.
关键词： Nanofilms,Spectral splitting,Nanomaterials,Thermal properties,Stability,Nanofluids,Optical properties,Cost,Nanowires,Hybrid photovoltaic-thermal (PV-T) collectors
更新于2025-09-23 15:21:01
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Simulational and experimental investigation on the wavefront sensing method based on near-field profile acquisition in high power lasers
摘要： This paper presents a novel wavefront sensing method based on near-field profile acquisition (NIA) to acquire the wavefront information. This method uses a cross mark at the focal plane of the spatial filter to directly obtain wavefront slope from the power spectral density (PSD) distribution of the output near-field profile. Principles of this method are introduced and the numerical simulation model is built. The influence of primary parameters on the measurement precision are analyzed and discussed. Based on the designed cross mark structure, an experiment is carried out in a multi-pass amplification high power laser and the wavefront of the pre-amplifier is reconstructed. Experimental results show that the difference between the reconstructed wavefronts by using the traditional Shack–Hartmann (SH) and the NIA wavefront sensing method is as small as 0.09 μm (peak-to-valley value).
关键词： Power spectral density,Near-field profile,Wavefront sensing,Wavefront
更新于2025-09-23 15:21:01
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Multilayer dielectric coated Fabry Perot spectral beam combiner for high power, narrowband, widely tunable laser applications
摘要： Spectral beam combination of tunable laser beams demonstrated, using a multilayer dielectric coated single cavity Fabry Perot (FP) filter. A stack of 19 layers using TiO2 and SiO2 was optimally designed and fabricated using an electron beam evaporation technique. This filter was characterized for transmission spectrum, surface morphology and laser induced damage threshold. The sharp transmission spectrum facilitated the spectral combination of closer wavelengths (< 10 nm) around 632.8 nm. This filter was utilized as an efficient spectral beam combiner as well as an amplified spontaneous emission (ASE) filter for the transmitting wavelength. This study finds direct application for tunable, multi-wavelength laser-based differential absorption lidar (DIAL) and atmospheric remote sensing applications. The application of this device was successfully demonstrated to spectrally combine high power, tunable copper vapor laser pumped dye laser beams. A mechanism to tune the FP transmission profile along with laser beam tunability was established.
关键词： Fabry Perot beam combiner,Widely tunable laser,Amplified spontaneous emission filtering,Angle tuning mechanism,Closer wavelength spectral beam combination
更新于2025-09-23 15:21:01