scholarly journals Geometrical Scaling of Antiresonant Hollow-Core Fibers for Mid-Infrared Beam Delivery

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 420
Author(s):  
Ang Deng ◽  
Wonkeun Chang
Keyword(s):  
Structural Parameters ◽  
Transmission Band ◽  
Confinement Loss ◽  
Hollow Core ◽  
Core Size ◽  
Core Diameter ◽  
Mid Infrared ◽  
The Core ◽  
Tubular Type ◽  
Beam Delivery

We numerically investigate the effect of scaling two key structural parameters in antiresonant hollow-core fibers—dielectric wall thickness of the cladding elements and core size—in view of low-loss mid-infrared beam delivery. We demonstrate that there exists an additional resonance-like loss peak in the long-wavelength limit of the first transmission band in antiresonant hollow-core fibers. We also find that the confinement loss in tubular-type hollow-core fibers depends strongly on the core size, where the degree of the dependence varies with the cladding tube size. The loss scales with the core diameter to the power of approximately −5.4 for commonly used tubular-type hollow-core fiber designs.

scholarly journals Characteristic Analysis and Structural Design of Hollow-Core Photonic Crystal Fibers with Band Gap Cladding Structures

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 284
Author(s):  
Bowei Wan ◽  
Lianqing Zhu ◽  
Xin Ma ◽  
Tianshu Li ◽  
Jian Zhang
Keyword(s):  
Photonic Crystal ◽  
Band Gap ◽  
Photonic Crystal Fibers ◽  
Relative Sensitivity ◽  
Confinement Loss ◽  
Hollow Core ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
The Core ◽  
Crystal Fibers

Due to their flexible structure and excellent optical characteristics hollow-core photonic crystal fibers (HC-PCFs) are used in many fields, such as active optical devices, communications, and optical fiber sensing. In this paper, to analyze the characteristics of HC-PCFs, we carried out finite element analysis and analyzed the design for the band gap cladding structure of HC-PCFs. First, the characteristics of HC19-1550 and HC-1550-02 in the C-band were simulated. Subsequently, the structural optimization of the seven-cell HC-1550-02 and variations in characteristics of the optimized HC-1550-02 in the wavelength range 1250–1850 nm were investigated. The simulation results revealed that the optimal number of cladding layers is eight, the optimal core radius is 1.8 times the spacing of adjacent air holes, and the optimal-relative thickness of the core quartz-ring is 2.0. In addition, the low confinement loss bandwidth of the optimized structure is 225 nm. Under the transmission bandwidth of the optimized structure, the core optical power is above 98%, the confinement loss is below 9.0 × 10−3 dB/m, the variation range of the effective mode field area does not exceed 10 μm2, and the relative sensitivity is above 0.9570. The designed sensor exhibits an ultra-high relative sensitivity and almost zero confinement loss, making it highly suitable for high-sensitivity gas or liquid sensing.

scholarly journals The influence of IONPs core size on their biocompatibility and activity in in vitro cellular models

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Natalia Janik-Olchawa ◽  
Agnieszka Drozdz ◽  
Damian Ryszawy ◽  
Maciej Pudelek ◽  
Karolina Planeta ◽  
...  
Keyword(s):  
Cell Lines ◽  
Therapeutic Potential ◽  
Proliferation Rate ◽  
Core Size ◽  
Phagocytic Cells ◽  
Migration Activity ◽  
Core Diameter ◽  
Cellular Models ◽  
The Core ◽  
The Impact

AbstractAlthough the key factor affecting the biocompatibility of IONPs is the core size, there is a lack of regular investigation concerning the impact of the parameter on the toxicity of these nanomaterials. Therefore, such studies were carried out in this paper. Their purpose was to compare the influence of PEG-coated-magnetite NPs with the core of 5, 10 and 30 nm on six carefully selected cell lines. The proliferation rate, viability, metabolic activity, migration activity, ROS levels and cytoskeleton architecture of cells have been evaluated for specified incubation periods. These were 24 and 72-h long incubations with IONPs administered in two doses: 5 and 25 µg Fe/ml. A decrease in viability was observed after exposure to the tested NPs for all the analyzed cell lines. This effect was not connected with core diameter but depended on the exposure time to the nanomaterials. IONPs increased not only the proliferation rate of macrophages—being phagocytic cells—but also, under certain conditions stimulated tumor cell divisions. Most likely, the increase in proliferation rate of macrophages contributed to the changes in the architecture of their cytoskeleton. The growth in the level of ROS in cells had been induced mainly by the smallest NPs. This effect was observed for HEK293T cells and two cancerous lines: U87MG (at both doses tested) and T98G (only for the higher dose). This requires further study concerning both potential toxicity of such IONPs to the kidneys and assessing their therapeutic potential in the treatment of glioblastoma multiforme.

scholarly journals Anti-Resonant Hollow Core Fibers with Modified Shape of the Core for the Better Optical Performance in the Visible Spectral Region—A Numerical Study

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 899 ◽  
Author(s):  
Hanna Stawska ◽  
Maciej Popenda ◽  
Elżbieta Bereś-Pawlik
Keyword(s):  
Optical Fibers ◽  
Wavelength Range ◽  
Numerical Study ◽  
Visible Spectral Region ◽  
Fused Silica ◽  
Confinement Loss ◽  
Hollow Core ◽  
The Core ◽  
Bending Loss ◽  
Bending Radius

In this paper, we present numerical studies of several different structures of anti-resonant, hollow core optical fibers. The cladding of these fibers is based on the Kagomé lattice concept, with some of the core-surrounding lattice cells removed. This modification, by creating additional, glass-free regions around the core, results in a significant improvement of some important optical fiber parameters, such as confinement loss (CL), bending loss (BL), and dispersion parameter (D). According to the conducted simulations (with fused silica glass being the structure’s material), CL were reduced from ~0.36 dB/m to ~0.16 dB/m (at 760 nm wavelength) in case of the structure with removed cells, and did not exceed the value of 1 dB/m across the 700–850 nm wavelength range. Additionally, proposed structure exhibits a remarkably low value of D—from 1.5 to 2.5 ps/(nm × km) at the 700–800 nm wavelength range, while the BL were estimated to be below 0.25 dB/m for bending radius of ~1.5 cm. CL and D were simulated, additionally, for structures made of acrylic glass polymethylmethacrylate, (PMMA), with similarly good results—DPMMA ∊ [2, 4] ps/(nm × km) and CLPMMA ≈ 0.13 dB/m (down from 0.41 dB/m), for the same spectral regions (700–800 nm bandwidth for D, and 760 nm wavelength for CL).

Theory and observations of waves on hollow-core vortices

1980 ◽  
Vol 99 (3) ◽  
pp. 495-511 ◽  
Author(s):  
Jakob J. Keller ◽  
M. P. Escudier
Keyword(s):  
Vortex Tube ◽  
Capillary Wave ◽  
Standing Waves ◽  
Wave Pattern ◽  
Interesting Case ◽  
Hollow Core ◽  
Core Size ◽  
Viscous Effects ◽  
Wave Problem ◽  
The Core

A linear non-homogeneous analysis is presented for the standing waves produced on the hollow core of an irrotational vortex by an arbitrary obstacle on the wall of the tube containing the vortex. The group-velocity criterion based upon Kelvin's corresponding dispersion relation predicts whether a certain asymptotic wave pattern appears upstream or downstream of the obstacle. The analysis leads to amplitude singularities for the standing waves at certain critical radii of the core. The particularly interesting case of a counter-helix for which the wave energy is propagating upstream appears for a first-mode angular disturbance. For this situation it seems to be possible that the helix ends in a hydraulic jump and is continued by a counter-helix downstream, as the core size gradually diminishes due to the deceleration of the flow caused by viscous effects (not included in the analysis). The capillary-wave pattern produced by surface tension is also considered. A brief outline for the analogous wave problem is given for the case where the fluid rotates like a rigid body.Photographic observations of hollow-core vortices in water flow are presented which confirm the qualitative predictions of the analysis, both for the response to an axisymmetric area contraction and also to a 90° bend at the downstream end of the vortex tube.

An Intensity Demodulated Refractive Index Sensor Based on A Hollow-Core Anti-Resonant Fiber

2022 ◽  
Author(s):  
Shidi Liu ◽  
Tianyu Yang ◽  
Liang Zhang ◽  
Ming Tian ◽  
Yuming Dong
Keyword(s):  
Refractive Index ◽  
Structural Parameters ◽  
High Sensitivity ◽  
Refractive Index Sensor ◽  
Hollow Core ◽  
Promising Candidate ◽  
Mid Infrared ◽  
Flow Through ◽  
Demodulation Method ◽  
High Absorption

Abstract A robust and simple mid-infrared hollow-core anti-resonant fiber (ARF) based refractive index (RI) sensor with an intensity demodulation method is presented and analyzed for monitoring liquid analytes. The ARF allows liquid analytes to flow through its hollow area for detection. To obtain ideal sensing performance, an epsilon negative (ENG) material is introduced into the selected anti-resonant tube. With the high absorption of the ENG material, only one fundamental mode is available for detection and is sensitive to the RI variation of analytes. Moreover, the effects of structural parameters on the sensing performances are discussed and analyzed to further understand the mechanism and optimization. The final result shows that the ARF sensor can exhibit a high sensitivity of -372.58 dB/RIU at a fixed wavelength within a broad RI range from 1.33 to 1.45, which covers most liquid analytes. It is a promising candidate for chemical and environmental analysis. Additionally, it has the potential for deep research to feed diverse applications.

scholarly journals Kagome Hollow Core Fiber-Based Mid-Infrared Dispersion Spectroscopy of Methane at Sub-ppm Levels

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3352 ◽  
Author(s):  
Karol Krzempek ◽  
Krzysztof Abramski ◽  
Michal Nikodem
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Difference Frequency Generation ◽  
Hollow Core ◽  
Large Core ◽  
Core Diameter ◽  
Mid Infrared ◽  
Core Fiber ◽  
Crystal Fibers ◽  
Long Fibers

In this paper, we demonstrate the laser-based gas sensing of methane near 3.3 µm inside hollow-core photonic crystal fibers. We exploit a novel anti-resonant Kagome-type hollow-core fiber with a large core diameter (more than 100 µm) which results in gas filling times of less than 10 s for 1.3-m-long fibers. Using a difference frequency generation source and chirped laser dispersion spectroscopy technique, methane sensing with sub-parts-per-million by volume detection limit is performed. The detection of ambient methane is also demonstrated. The presented results indicate the feasibility of using a hollow-core fiber for increasing the path-length and improving the sensitivity of the mid-infrared gas sensors.

scholarly journals Low-loss single-mode hybrid-lattice hollow-core photonic-crystal fibre

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Foued Amrani ◽  
Jonas H. Osório ◽  
Frédéric Delahaye ◽  
Fabio Giovanardi ◽  
Luca Vincetti ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Single Mode ◽  
Confinement Loss ◽  
Hollow Core ◽  
Low Loss ◽  
Fibre Optics ◽  
Photonic Crystal Fibre ◽  
Single Mode Operation ◽  
Mode Operation ◽  
Beam Delivery

AbstractRemarkable recent demonstrations of ultra-low-loss inhibited-coupling (IC) hollow-core photonic-crystal fibres (HCPCFs) established them as serious candidates for next-generation long-haul fibre optics systems. A hindrance to this prospect and also to short-haul applications such as micromachining, where stable and high-quality beam delivery is needed, is the difficulty in designing and fabricating an IC-guiding fibre that combines ultra-low loss, truly robust single-modeness, and polarisation-maintaining operation. The design solutions proposed to date require a trade-off between low loss and truly single-modeness. Here, we propose a novel IC-HCPCF for achieving low-loss and effective single-mode operation. The fibre is endowed with a hybrid cladding composed of a Kagome-tubular lattice (HKT). This new concept of a microstructured cladding allows us to significantly reduce the confinement loss and, at the same time, preserve truly robust single-mode operation. Experimental results show an HKT-IC-HCPCF with a minimum loss of 1.6 dB/km at 1050 nm and a higher-order mode extinction ratio as high as 47.0 dB for a 10 m long fibre. The robustness of the fibre single-modeness is tested by moving the fibre and varying the coupling conditions. The design proposed herein opens a new route for the development of HCPCFs that combine robust ultra-low-loss transmission and single-mode beam delivery and provides new insight into IC guidance.

scholarly journals A Comparative Analysis between Low Loss Kagome Structured THz Hollow Core and Porous Core PCF

2020 ◽  
Vol 16 (2) ◽  
Author(s):  
Mohaiminul Islam ◽  
Md. Anwar Hossain ◽  
Fahmida Haque
Keyword(s):  
Bulk Material ◽  
Single Mode ◽  
Confinement Loss ◽  
Hollow Core ◽  
Kagome Lattice ◽  
Low Loss ◽  
Material Loss ◽  
Core Diameter ◽  
Kagomé Lattice ◽  
Porous Core

This paper presents a comparative study between a porous core kagome lattice photonic crystal fiber (PCF) and a air filled Hollow core kagome lattice PCF (HC-PCF), which acts as a low loss and polarization maintaining tera hertz (THz) waveguide. Proposed PCFs are simulated using finite element method (FEM), including the effective material loss (EML), confinement loss and single mode propagation. Cyclic olefin copolymer, also known as TOPAS material have been chosen for the air micro structured inhibited coupled design of PCF which has the lowest bulk material absorption loss of 0.2 cm-1. Expressions are given to asses this optimization and the result are shown for the variation of core diameter from 425 μm to 600 μm for both the Hollow core and porous core PCFs and for the comparison with porous core the optimized porosity taken as 60% and 70% along with the frequency of 1THz. The analysis results approximately 80% to 90% improvement in losses in case of passing THz waves through HC-PCF rather than Porous core PCF. By varying core parameter such as core porosity and core diameter and strut width at 1THz, the goal is to show an optimized solution consisting of low EML and confinement loss for both of the wave guidance and comparing the results to analyze and hence finding out a better solution.

Nondestructive determination of the core size of a hollow-core photonic bandgap fiber using Fabry–Perot interference

2018 ◽  
Vol 43 (13) ◽  
pp. 3045 ◽  
Author(s):  
Xiaobin Xu ◽  
Xiaoyang Wang ◽  
Taotao Zhu ◽  
Fuyu Gao ◽  
Ningfang Song
Keyword(s):  
Photonic Bandgap ◽  
Hollow Core ◽  
Core Size ◽  
Photonic Bandgap Fiber ◽  
Nondestructive Determination ◽  
The Core ◽  
Fabry Perot

scholarly journals Second-Order Vector Mode Propagation in Hollow-Core Antiresonant Fibers

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 381 ◽  
Author(s):  
Lili Li ◽  
Limin Xiao
Keyword(s):  
Optical Tweezers ◽  
Short Pulse ◽  
Transmission Band ◽  
Second Order ◽  
Confinement Loss ◽  
Coupling Mechanism ◽  
Mode Propagation ◽  
Hollow Core ◽  
Vector Mode ◽  
Ultra Short Pulse

Second-order vector modes, possessing doughnut-shaped intensity distribution with unique polarization, are widely utilized in material micromachining, optical tweezers, and high-resolution microscopy. Since the hollow-core fiber can act as a flexible and robust optical waveguide for ultra-short pulse delivery and manipulation, high-order vector modes guided in hollow-core fibers will have huge potential in many advanced applications. We firstly reveal that a second-order vector mode can be well guided in a hollow-core antiresonant fiber with the suppression of the fundamental mode and other second-order vector modes at the red side of transmission band. We interpret our observation through a phase-matched coupling mechanism between core modes and coupled cladding modes. A single second-order vector mode such as TE01, TM01, or HE21 can be guided with low confinement loss at specific wavelengths with appropriate structure parameters. Our proposed hollow-core fibers have a modal engineering function which will open up a new avenue toward the single second-order vector mode propagation and its fiberized applications.

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