- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Design and Characterization of an Ultra Low Loss, Dispersion-Flattened Slotted Photonic Crystal Fiber for Terahertz Application
摘要： A novel photonic crystal fiber (PCF) based on TOPAS, consisting only rectangular slots is presented and analyzed in this paper. The PCF promises not only an extremely low effective material loss (EML) but also a flattened dispersion over a broad frequency range. The modal characteristics of the proposed fiber have been thoroughly investigated using finite element method. The fiber confirms a low EML of 0.009 to 0.01 cm?1 in the frequency range of 0.77–1.05 THz and a flattened dispersion of 0.22 ± 0.01 ps/THz/cm. Besides, some other significant characteristics like birefringence, single mode operation and confinement loss have also been inspected. The simplicity of the fiber makes it easily realizable using the existing fabrication technologies. Thus it is anticipated that the new fiber has the potential to ensure polarization preserving transmission of terahertz signals and to serve as an efficient medium in the terahertz frequency range.
关键词： dispersion,micro-structured fibers,terahertz,photonic crystal fibers,effective material loss
更新于2025-09-09 09:28:46
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Crosstalk-Aware Core and Spectrum Assignment in a Multicore Optical Link with Flexible Grid
摘要： Multicore Fibers (MCFs) are one of the main technological enablers for Space Division Multiplexing. In principle, MCFs could scale the fiber capacity by a factor equal to the number of cores, but in practice such increase is hindered by transmission impairments due to the inter-core crosstalk between adjacent lit cores. The entity of such crosstalk depends on the number of cores and on their disposition within the fiber cladding, but also on the baud rate and modulation format used for transmission. As first MCF applications are expected over point-to-point systems, in this study we concentrate on the resource allocation over a single link. Specifically, we study the Baud rate, Modulation format, Core and Spectrum Assignment (BMCSA) problem in a multicore flexi-grid link, considering distance-adaptive reaches for different baud rates, modulation formats and crosstalk impairments. We show that the problem is NP-hard and provide two integer linear programs, as well as heuristic approaches to solve it over large/practical traffic instances. Our problem formulations incorporate modelling of the exact inter-core crosstalk contributions depending on the number of lit neighbor cores. Numerical results are provided in a high-spatial-efficiency 19-core fiber considering different transmission impairment conditions.
关键词： Multi-core optical fibers,Inter-core crosstalk,Core and Spectrum Assignment
更新于2025-09-09 09:28:46
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High-efficiency, high-gain, all-fibered double-pass configuration for low-duty-cycle temporally shaped nanosecond pulse amplification
摘要： A high-gain fiber amplifier at 1053 nm with a double-pass configuration is proposed. Compared to the Faraday-based double-pass structures, the pump efficiency is almost doubled, and the optical signal-to-noise ratio is improved as well. The effects of fiber length and the insertion loss of elements between two passes on the efficiency are studied experimentally, which is meaningful for the optimization of double-pass amplifiers. Using the fibered polarized beam splitters allow for the orthogonal propagation of forward and the backward signals on the same polarization-maintaining fiber, the polarization mode dispersion in the amplifier is hence totally avoided. With this structure, over 50-dB gain is obtained at pump power of 800 mW for a 1053-nm, 1-Hz nanosecond pulse.
关键词： Laser amplifiers,Ytterbium,Lasers,Polarization-maintaining,Fibers
更新于2025-09-09 09:28:46
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Surface-enhanced Raman spectroscopy (SERS) in cotton fabrics analysis
摘要： This article presents some aspects of application the dispersive Micro-Raman Spectroscopy in textile fibers analysis. Research were dedicated to the methodology of surface enhancement Raman spectroscopy (SERS) studies on cotton fabric and possibility of its application in fibers characterization. Studies were carried out on dyed cotton fabrics modified by silver nanowires (AgNWs). Three reactive dyes (blue, yellow, red) and four color intensities (0.5%, 1%, 2% and 5%) were used. AgNWs colloid was deposited on undyed and dyed cotton fabrics by dipping and drying method. Dyed fabrics were examined by spectroscopic methods: FTIR ATR, Raman, UV-Vis Diffuse Reflectance Spectroscopy, Fluorescence Spectroscopy. Raman signal enhancement phenomena occurring on the silver nanoparticles increases the possibility of fiber and dye identification especially in the case of dyes used in cotton dyeing reveals fluorescence.
关键词： UV-Vis Diffuse Reflectance Spectroscopy,SERS,Fluorescence Spectroscopy,reactive dyes,FTIR ATR,Micro-Raman spectroscopy,Cotton fibers
更新于2025-09-09 09:28:46
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Infiltrated Photonic Crystal Fibers for Sensing Applications
摘要： Photonic crystal ?bers (PCFs) are a special class of optical ?bers with a periodic arrangement of microstructured holes located in the ?ber’s cladding. Light con?nement is achieved by means of either index-guiding, or the photonic bandgap effect in a low-index core. Ever since PCFs were ?rst demonstrated in 1995, their special characteristics, such as potentially high birefringence, very small or high nonlinearity, low propagation losses, and controllable dispersion parameters, have rendered them unique for many applications, such as sensors, high-power pulse transmission, and biomedical studies. When the holes of PCFs are ?lled with solids, liquids or gases, unprecedented opportunities for applications emerge. These include, but are not limited in, supercontinuum generation, propulsion of atoms through a hollow ?ber core, ?ber-loaded Bose–Einstein condensates, as well as enhanced sensing and measurement devices. For this reason, in?ltrated PCF have been the focus of intensive research in recent years. In this review, the fundamentals and fabrication of PCF in?ltrated with different materials are discussed. In addition, potential applications of in?ltrated PCF sensors are reviewed, identifying the challenges and limitations to scale up and commercialize this novel technology.
关键词： optical fiber sensors,photonic crystal fibers,optofluidics,plasmonic sensors,liquid crystals
更新于2025-09-09 09:28:46
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A Double-Cladding Single Polarization Photonic Crystal Fiber and Its Structure Deviation Tolerance
摘要： We propose a novel broadband single-polarization single-mode photonic crystal fiber (SPSM-PCF) with hexagonally latticed circular airholes. Combined with our fabricated polarization maintaining fiber, it has demonstrated that the enlarged air holes in the outmost layer are superior for the confinement loss reduction. At the optimized parameters, the wavelength of SPSM region is ranging from 1.52 μm to 2.13 μm, where only y-polarized fundamental mode exists and the confinement loss is 0.051 dB/km at 1.55 μm. The influence of realistic fabrication errors involving structure deviation on SPSM operation has also been systematically investigated.
关键词： fiber properties.,Fiber design and fabrication,photonic crystal fibers,single-polarization single mode
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Systems Engineering Symposium (ISSE) - Rome, Italy (2018.10.1-2018.10.3)] 2018 IEEE International Systems Engineering Symposium (ISSE) - Implementation of support tools for the presumptive diagnosis of Glaucoma through identification and processing of medical images of the human eye
摘要： In medicine, the diagnosis of diseases by means of image processing has had great acceptability and credibility, which is why it has been able to explore in depth the theme, taking advantage of mainly which is a non-invasive method within the clinical study. Glaucoma is considered as a group of diseases that damages the optic nerve to the point of causing blindness in the eye, with the disadvantage of in most cases do not exhibit early symptoms. Through this work, the processing biomedical images to locate the parameters considered most relevant within images obtained from the back of the eye to make the determination of the existence or not of Glaucoma, a disease that mainly affects physically the dimensions and proportions of the cup and the optical disc. It gets the value of the reason cup/disc and is additional to the characteristics of the rule ISNT, both parameters considered of great importance in the diagnosis of glaucoma. The results obtained serve as a tool to support the specialist in ophthalmology and optometry in conjunction with a presumptive diagnosis of glaucoma, this way it looks for the early detection and prevention of this disease.
关键词： ISNT,visual field,cup-disc,Glaucoma,nerve fibers,image processing,optic nerve
更新于2025-09-09 09:28:46
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Soft optoelectronic sensory foams with proprioception
摘要： In a step toward soft robot proprioception, and therefore better control, this paper presents an internally illuminated elastomer foam that has been trained to detect its own deformation through machine learning techniques. Optical fibers transmitted light into the foam and simultaneously received diffuse waves from internal reflection. The diffuse reflected light was interpreted by machine learning techniques to predict whether the foam was twisted clockwise, twisted counterclockwise, bent up, or bent down. Machine learning techniques were also used to predict the magnitude of the deformation type. On new data points, the model predicted the type of deformation with 100% accuracy and the magnitude of the deformation with a mean absolute error of 0.06°. This capability may impart soft robots with more complete proprioception, enabling them to be reliably controlled and responsive to external stimuli.
关键词： machine learning,elastomer foam,soft robots,optical fibers,proprioception
更新于2025-09-09 09:28:46
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Charge‐Induced Shifts in Chiral Surface Plasmon Modes in Gold Nanorod Assemblies
摘要： A detailed investigation of the effect of electron injection on the chiral plasmon modes of helical nanorod assemblies is presented. An increased surface plasmon frequency of the electron gas due to the addition of electrons leads to a blue-shift in the corresponding chiral surface plasmon modes. The mechanism behind the shift in plasmonic chirality due to nanorod charging is investigated using theoretical simulations. Charging of the nanorods alters the surface electron density, thereby modifying the plasma frequency and causing a change in the dielectric function. The nature of the plasmon shift and the intensity of chiral surface plasmons are found to be largely dependent on the extent of electron addition. At extended periods of time, the blue shifted band slowly shifts back toward the red, due to transfer of electrons back to the medium, leading to discharging of the nanorods.
关键词： charging effects,plasmonic chirality,electromagnetic modeling,Au nanorods,amyloid fibers
更新于2025-09-04 15:30:14
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Selection and Quantification of Objects in Microscopic Images: from Multi-Criteria to Multi-Threshold Analysis
摘要： Due to the increased number of applications of both microscopic imaging and image analysis including biomedical studies, the design of specialized algorithms and tools to facilitate quantitative assessment of objects in the image content is of urgent need. Recently, a number of approaches ranging from object counting by machine learning methods to statistical image analysis have been suggested and successfully implemented to resolve the cell quantification problem. Here, we revisit the above problem considering samples where objects presented in the same images have to be explicitly distinguished and quantified without involving any dedicated experimental setting like differential fluorescent staining. We consider several possible classification criteria and show explicitly how their combination in a single algorithm can be used to improve results in complex images where single criteria-based rules inevitably fail. Finally, we suggest a possible approach for the analysis of non-homogeneous images based on combining object selection results for different threshold values thus enhancing the algorithm from multi-criteria to multi-threshold analysis. To demonstrate the performance of the suggested solutions, we show several prominent examples of complex structures ranging from images containing both live and apoptotic cells as well as containing mixtures of globular and fibrous forms of heat-shock protein IbpA.
关键词： Microscopy,Image analysis,Apoptotic,Cell sub-populations,Fibers
更新于2025-09-04 15:30:14