Internal structuring of silica glass fibers: Requirements for scattered light applicators for the usability in medicine

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Jenny Köcher ◽  
Verena Knappe ◽  
Manuela Schwagmeier
Keyword(s):  
Optical Fiber ◽  
Glass Fibers ◽  
Scattered Light ◽  
The Core ◽  
Processing Power ◽  
Silica Fibers ◽  
Bending Radius ◽  
Photon Process ◽  
Fixation Apparatus ◽  
Radiation Profile

AbstractBackground:Diffuser fibers have been used for some time in the fields of laser-induced thermotherapy and photodynamic therapy. For their applicability the breaking strength, the thermostability and a homogeneous radiation profile are of great importance. Flexible applicators offer special benefits because they introduce a totally new range of application possibilities.Objective:The aim of the presented investigations was to develop a totally new flexible diffuser fiber generation which can be produced cheaper and without the use of any further materials. For this purpose it was proposed to induce scattering micro dots directly into silica fibers by generating a local change of the refractive index in the core of the optical fiber. The resulting diffuser was expected to create a homogeneous radiation profile containing at least 80% of the light coupled into the optical fiber, i.e. less than 20% prograde (forward) emission.Materials and methods:On the basis of former research results, scattering micro dots were induced linearly into the core of an optical silica fiber through a multiple photon process using a femtosecond laser. In addition to the macroscopic optical control by means of a microscope, the form of the radiation profile was examined as well as the non-scattered forward emission which depends on a variety of influencing factors. The processing was optimized according to the observations made. The thermostability of the developed prototypes was assessed by using a thermocamera, and the minimal bending radius was determined. Finally the prototypes were tested and validatedResults:An influence of the processing power, the number and radial position of the scattering micro dots as well as the therapeutic coupled-in wavelength onto the form of the radiation profile and the non-scattered forward emission was determined. Both the form of the radiation profile and the prograde emission were found to be independent of the therapeutic laser power coupled into the fiber. The developed prototype had a nearly homogeneous radiation profile, a forward emission of 12.8±2.1% in average, and a minimum bending radius of 31±6 mm.Conclusion:The non-scattered forward emission of the developed diffusers was within the objective of below 20% and the radiation profile was very nearly homogeneous. In order to improve the reproducibility of the production process, an improved fixation apparatus needs to be developed.

Comparative crosstalk performance analysis of different configurations of heterogeneous multicore fiber

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Umar Farooque ◽  
Rakesh Ranjan
Keyword(s):  
Refractive Index ◽  
Mode Coupling ◽  
The Other ◽  
Heterogeneous Multicore ◽  
Coupled Mode ◽  
The Core ◽  
Bending Radius ◽  
Multicore Fiber ◽  
The Impact ◽  
Core Pitch

AbstractIn order to select the heterogeneous multicore fiber (MCF) configuration with ultra-low crosstalk and low peak bending radius, comparative crosstalk analysis have been done for the three possible core configurations, namely, Configuration 1 - different refractive index (R.I.) and different radius, Configuration 2 - different R.I., and Configuration 3 - different radius. Using the coupled mode equation and the simplified expressions of mode coupling coefficient (MCC) for different configurations of heterogeneous cores, the crosstalk performance of all the heterogeneous MCF configurations along with the homogeneous MCF have been investigated analytically with respect to core pitch (D) and fiber bending radius (${R}_{b}$). Further, these expressions of MCC have been extended to obtain the simplified expressions of MCC for the estimation of crosstalk levels in respective trench-assisted (TA) heterogeneous MCF configurations. It is observed from the analysis that in Configuration 1, crosstalk level is lowest and the rate of decrease in the crosstalk with respect to the core pitch is highest compared to the other configurations of heterogeneous MCF. The values of crosstalk obtained analytically have been validated by comparing it with the values obtained from finite element method (FEM) based numerical simulation results. Further, we have investigated the impact of a fixed percent change (5%) in the core parameters (radius and/or R.I.) of one of the core of a homogeneous MCF, to realize the different heterogeneous MCF configurations, on the variations in crosstalk levels, difference in the mode effective refractive index of the core 1 and core 2 ($\Delta {n}_{eff}={n}_{eff1}-{n}_{eff2}$), and the peak bending radius (${R}_{pk}$). For the same percent variations (5%) in the core parameters (radius and/or R.I.) of different configurations of cores (Config. 1-Config. 3), Config. 1 MCF has highest variation in $\Delta {n}_{eff}$ value compared to other configurations of MCF. Further, this highest variation in $\Delta {n}_{eff}$ value of Config. 1 MCF results in smallest peak bending radius. The smaller value of peak bending radius allows MCF to bend into smaller radius. Therefore, Configuration 1 is the potential choice for the design of MCF with smaller peak bending radius and ultra-low crosstalk level compared to the other configurations of SI-heterogeneous MCF.

scholarly journals Light-Scattering Simulations from Spherical Bimetallic Core–Shell Nanoparticles

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 359
Author(s):  
Francesco Ruffino
Keyword(s):  
Optical Properties ◽  
Light Scattering ◽  
Bimetallic Nanoparticles ◽  
Dominant Role ◽  
Scattered Light ◽  
Specific Interaction ◽  
Surface Enhanced Raman Spectroscopy ◽  
Localized Surface Plasmon ◽  
Core Shell ◽  
The Core

Bimetallic nanoparticles show novel electronic, optical, catalytic or photocatalytic properties different from those of monometallic nanoparticles and arising from the combination of the properties related to the presence of two individual metals but also from the synergy between the two metals. In this regard, bimetallic nanoparticles find applications in several technological areas ranging from energy production and storage to sensing. Often, these applications are based on optical properties of the bimetallic nanoparticles, for example, in plasmonic solar cells or in surface-enhanced Raman spectroscopy-based sensors. Hence, in these applications, the specific interaction between the bimetallic nanoparticles and the electromagnetic radiation plays the dominant role: properties as localized surface plasmon resonances and light-scattering efficiency are determined by the structure and shape of the bimetallic nanoparticles. In particular, for example, concerning core-shell bimetallic nanoparticles, the optical properties are strongly affected by the core/shell sizes ratio. On the basis of these considerations, in the present work, the Mie theory is used to analyze the light-scattering properties of bimetallic core–shell spherical nanoparticles (Au/Ag, AuPd, AuPt, CuAg, PdPt). By changing the core and shell sizes, calculations of the intensity of scattered light from these nanoparticles are reported in polar diagrams, and a comparison between the resulting scattering efficiencies is carried out so as to set a general framework useful to design light-scattering-based devices for desired applications.

scholarly journals In-Process Diameter Measurement Technique for Micro-Optical Fiber with Standing Wave Illumination

2021 ◽  
Author(s):  
Masaki Michihata ◽  
Zhao Zheng ◽  
Daiki Funaiwa ◽  
Sojiro Murakami ◽  
Shotaro Kadoya ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Standing Wave ◽  
Dynamic Range ◽  
Scattered Light ◽  
High Dynamic Range ◽  
Measurement Range ◽  
Diameter Distribution ◽  
Process Measurement ◽  
Air Turbulence ◽  
Tapered Optical Fiber

AbstractIn this paper, we propose an in-process measurement method of the diameter of micro-optical fiber such as a tapered optical fiber. The proposed technique is based on analyzing optically scattered light generated by standing wave illumination. The proposed method is significant in that it requires an only limited measurement range and does not require a high dynamic range sensor. These properties are suitable for in-process measurement. This experiment verified that the proposed method could measure a fiber diameter as stable as ± 0.01 μm under an air turbulence environment. As a result of comparing the measured diameter distribution with those by scanning electron microscopy, it was confirmed that the proposed method has a measurement accuracy better than several hundred nanometers.

scholarly journals Microcautery based on zinc metallic nanoparticles photodeposited on the core of an optical fiber

2017 ◽  
Vol 392 ◽  
pp. 492-497 ◽  
Author(s):  
P. Zaca-Morán ◽  
C.F. Pastelín ◽  
C. Morán ◽  
G.F. Pérez-Sánchez ◽  
F. Chávez
Keyword(s):  
Optical Fiber ◽  
Metallic Nanoparticles ◽  
The Core

Fabrication of Optical Fiber Sensors Based on Femtosecond Laser Micro Machining

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Fengfeng Zhou ◽  
Seunghwan Jo ◽  
Xingyu Fu ◽  
Jung-Ting Tsai ◽  
Martin Byung-Guk Jun
Keyword(s):  
Refractive Index ◽  
Femtosecond Laser ◽  
Optical Fiber ◽  
Refractive Index Change ◽  
Optical Fiber Sensors ◽  
Objective Lens ◽  
Machining Parameters ◽  
Fiber Sensors ◽  
The Core ◽  
First Time

Abstract In this research, we proposed fabrication process of optical fiber sensors using femtosecond laser and their applications. A beam of femtosecond laser was focused by an objective lens in the optical fiber. By testing different conditions, a group of machining parameters was found that achieve a minimum machining resolution of 3.2 μm. To ablate the core of the optical fiber, which is buried deep inside the cladding, precisely, part of the cladding was removed to expose the core as close as possible to the air. By making a complex pattern to modify the optical path of the laser inside an optical fiber, a sensitivity of 942.8–1015.6 nm per refractive index unit (nm/RIU) was obtained for liquid refractive index sensing. For another sensor, a sensitivity of 1.38 × 105 nm/RIU was obtained, which is high enough to detect small amount of refractive index change of air. It is known to be the first time that we fabricated a complex microstructure in an optical fiber to modify the propagation of the light using femtosecond laser. This research shows the possibility of a complex modification of light in an optical fiber using laser machining.

Towards a Programming Model for Ubiquitous Computing

2011 ◽  
pp. 634-648
Author(s):  
Jorge Barbosa ◽  
Fabiane Dillenburg ◽  
Alex Garzão ◽  
Gustavo Lermen ◽  
Cristiano Costa
Keyword(s):  
Mobile Computing ◽  
Ubiquitous Computing ◽  
Context Awareness ◽  
Programming Model ◽  
Distributed Applications ◽  
Portable Devices ◽  
Heterogeneous Devices ◽  
The Core ◽  
Processing Power ◽  
Execution Environment

Mobile computing is been driven by the proliferation of portable devices and wireless communication. Potentially, in the mobile computing scenario, the users can move in different environments and the applications can automatically explore their surroundings. This kind of context-aware application is emerging, but is not yet widely disseminated. Based on perceived context, the application can modify its behavior. This process, in which software modifies itself according to sensed data, is named Adaptation. This constitutes the core of Ubiquitous Computing. The ubiquitous computing scenario brings many new problems such as coping with the limited processing power of mobile devices, frequent disconnections, the migration of code and tasks between heterogeneous devices, and others. Current practical approaches to the ubiquitous computing problem usually rely upon traditional computing paradigms conceived back when distributed applications where not a concern. Holoparadigm (in short Holo) was proposed as a model to support the development of distributed systems. Based on Holo concepts, a new programming language called HoloLanguage (in short, HoloL) was created. In this chapter, we propose the use of Holo for developing and executing ubiquitous applications. We explore the HoloL for ubiquitous programming and propose a full platform to develop and execute Holo programs. The language supports mobility, adaptation, and context awareness. The execution environment is based on a virtual machine that implements the concepts proposed by Holo. The environment supports distribution and strong code mobility.

scholarly journals E-Knitted Textile with Polymer Optical Fibers for Friction and Pressure Monitoring in Socks

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 3011 ◽  
Author(s):  
Claire Guignier ◽  
Brigitte Camillieri ◽  
Michel Schmid ◽  
René M. Rossi ◽  
Marie-Ange Bueno
Keyword(s):  
Mechanical Properties ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Knitted Fabric ◽  
Bending Rigidity ◽  
Pressure Monitoring ◽  
Polymer Optical Fiber ◽  
Bending Radius ◽  
Polymer Optical Fibers ◽  
Knitted Structure

The objective of this paper is to study the ability of polymer optical fiber (POF) to be inserted in a knitted fabric and to measure both pressure and friction when walking. Firstly, POF, marketed and in development, have been compared in terms of the required mechanical properties for the insertion of the fiber directly into a knitted fabric on an industrial scale, i.e. elongation, bending rigidity, and minimum bending radius before plastic deformation. Secondly, the chosen optical fiber was inserted inside several types of knitted fabric and was shown to be sensitive to friction and compression. The knitted structure with the highest sensitivity has been chosen for sock prototype manufacturing. Finally, a feasibility study with an instrumented sock showed that it is possible to detect the different phases of walking in terms of compression and friction.

Identification of Nanocrystalline Inclusions in Bismuth-Doped Silica Fibers and Preforms

2016 ◽  
Vol 22 (5) ◽  
pp. 987-996 ◽  
Author(s):  
Liudmila D. Iskhakova ◽  
Filipp O. Milovich ◽  
Valery M. Mashinsky ◽  
Alexander S. Zlenko ◽  
Sergey E. Borisovsky ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Room Temperature ◽  
Optical Loss ◽  
Laser Generation ◽  
Dopant Distribution ◽  
X Ray ◽  
The Core ◽  
Silica Fibers ◽  
Transmission Electron ◽  
Bismuth Concentration

AbstractThe nature of nanocrystalline inclusions and dopant distribution in bismuth-doped silicate fibers and preforms are studied by scanning and transmission electron microscopy, and energy and wavelength-dispersive X-ray microanalysis. The core compositions are Bi:SiO2, Bi:Al2O3–SiO2, Bi:GeO2–SiO2, Bi:Al2O3–GeO2–SiO2, and Bi:P2O5–Al2O3–GeO2–SiO2. Nanocrystals of metallic Bi, Bi2O3, SiO2, GeO2, and Bi4(GeO4)3 are observed in these glasses. These inclusions can be the reason for the background optical loss in bismuth-doped optical fibers. The bismuth concentration of 0.0048±0.0006 at% is directly measured in aluminosilicate optical fibers with effective laser generation (slope efficiency of 27% at room temperature).

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