This study proposes a photonic crystal fiber made of fused silica glass, with the core infiltrated with tetrachloroethylene (C
2
Cl
4
) as a new source of supercontinuum (SC) spectrum. We studied ...numerically the guiding properties of the several different fiber structures in terms of characteristic dispersion, mode area, and attenuation of the fundamental mode. Based on the results, the structural geometries of three C
2
Cl
4
-core photonic crystal fibers were optimized in order to support the broadband SC generations. The first fiber structure with lattice constant 1.5 μm and filling factor 0.4 operates in all-normal dispersion. The SC with a broadened spectral bandwidth of 0.8–2 μm is generated by a pump pulse with a central wavelength of 1.56 μm, 90 fs duration and energy of 1.5 nJ. The second proposed structure, with lattice constant 4.0 μm and filling factor 0.45, performs an anomalous dispersion for wavelengths longer than 1.55 μm. With the same pump pulse as the first fiber, we obtained the coherence SC spectrum in an anomalous dispersion range with wavelength range from 1 to 2 μm. Meanwhile, the third selected fiber (lattice constant 1.5 μm, filling factor 0.55) has two zero dispersion wavelengths at 1.04 μm and 1.82 μm. The octave-spanning of the SC spectrum formed in this fiber was achieved in the wavelength range of 0.7–2.4 μm with an input pulse whose optical properties are 1.03 μm wavelength, 120 fs duration and energy of 2 nJ. Those fibers would be good candidates for all-fiber SC sources as cost-effective alternatives to glass core fibers.
In this research, the structural properties, surface morphology, and magnetic characteristics of nanostructured ternary ferromagnetic alloys grown by a cost‐effective and effortless two‐step ...electrochemical deposition method on indium tin oxide (ITO) substrates with and without a galvanostatic pretreatment process (GPP) were examined. The GPP was applied at various pretreatment current densities (PCDs) such as −10, −20, and − 30 mA/cm2. The effect of the PCD on the Ni, Co, and Fe contents is found to be insignificant and all resultant Ni‐Co‐Fe thin films show an abnormal co‐deposition. The films have nano‐sized crystallites ranging from 17.3 to 19.6 nm and showed a face‐centered cubic structure with the 111 preferential growth. Compared to the non‐GPP applied Ni‐Co‐Fe film, growing the ternary Ni‐Co‐Fe film on ITO at the PCD of −30 mA/cm2 causes an improvement in the crystal quality and a reduction in the particle size from 150 ± 50 to 70 ± 20 nm. A decrement in the surface roughness and coercivity was also achieved by applying the GPP at the PCD of −30 mA/cm2, but the opposite is true for the GPP performed at the PCD of −10 mA/cm2. The GPP has an effect on the magnetic Squareness Ratio (SQR), but the influence of the PCD on the SQR parameter is negligible. The obtained findings reveal that the properties of the Ni‐Co‐Fe/ITO ternary alloys can be tuned through the GPP applied in various PCDs.
Highlights
• The effect of the PCD on the Ni, Co, and Fe contents is found to be insignificant.
• The films have nano‐sized crystallites and showed a face‐centered cubic structure with the 111 preferential growth.
• The analysis reveals that the GPP changes the crystal quality, Hc parameter, surface roughness, and particle size of the films.
• The GPP has an effect on the magnetic squareness ratio (SQR), but the influence of the PCD on the SQR parameter is negligible.
• The films had nano‐sized crystallites ranging from 17.3 to 19.6 nm.
• The films were ferromagnetic, and the Hc and SQR parameters of the films ranged from 30.2 to 42.7 Oe and from 8.8% to 19.6%.
The structural properties, morphology, and magnetic characteristics of Ni‐Co‐Fe/ITO ternary alloys.
In this paper, we studied the effect of the 2D epoxy thin films’ shape with equilateral triangle and square structures, and matrix size Lx × Ly of (10 × 9), (20 × 19), (30 × 29), and (40 × 39) with ...equilateral triangle structure and (10 × 10), (20 × 20), (30 × 30), and (40 × 40) with the square structure on their mechanical properties such as strain (ɛ), stress (σ), Young stress (E), and shear strain (G) by using the Monte Carlo simulation method. The results show that when the shape of the 2D epoxy thin film is changed from an equilateral triangle structure to a square structure, the values of σ, E, and G decreased sharply. In addition, when the matrix size is increased from (10 × 9) to (20 × 19), (30 × 29), and (40 × 39) with an equilateral triangle structure and from (10 × 10) to (20 × 20), (30 × 30), and (40 × 40) with a square structure, σ slightly increased, but E and G decreased slightly. These results prove that the influence of structure shape on the mechanical properties of the 2D epoxy thin film is very large. The strain stress on the epoxy 2D thin film with an equilateral triangle structure and with a matrix size of (30 × 29) has a value of σ = 63.3 MPa. This result is consistent with the experimental result that σ of bulk epoxy has the maximum value of σmax = 64.76 MPa. The results are the basis for experimental research in future studies on practical applications of epoxy-thin films. In these cases, when thin films with equilateral triangle structures are used in biomedical fields, high stresses are required (such as replacement material for adaxial onion epidermis and fibrin and collagen with low stress).
We report on the feasibility of short-wavelength transmission window modification in anti-resonant hollow core fibers using post-processing by hydrofluoric (HF) acid etching. Direct drawing of ...stacked anti-resonant hollow core fibers with sub-micron thin cladding capillary membranes is technologically challenging, but so far this has been the only proven method of assuring over an octave-spanning transmission windows across the visible and UV wavelengths. In this study we revealed that low HF concentration allows us to reduce the thickness of the cladding capillary membranes from the initial 760 nm down to 180 nm in a controlled process. The glass etching rates have been established for different HF concentrations within a range non-destructive to the anti-resonant cladding structure. Etching resulted in spectral blue-shifting and broadening of anti-resonant transmission windows in all tested fiber samples with lengths between 15 cm and 75 cm. Spectrally continuous transmission, extending from around 200 nm to 650 nm was recorded in 75 cm long fibers with cladding membranes etched down to thickness of 180 nm. The experiment allowed us to verify the applicability and feasibility of controlling a silica fiber post-processing technique, aimed at broadening of anti-resonant transmission windows in hollow core fibers. A practical application of the processed fiber samples is demonstrated with their simple butt-coupling to light-emitting diodes centered at various ultraviolet wavelengths between 265 nm and 365 nm.
This study aims to provide new insights into the influencing factors of the Earth (low temperature, depth, and annealing time) on the heterogeneous kinetics of bulk Fe2O3 by the molecular dynamics ...simulation method. The obtained results show that there is an influence of the low temperature corresponding to the temperature of liquefied gases, such as helium (4.212 K), nitrogen (77 K), argon (83.8058 K), oxygen (90 K), and carbon (194.5 K), the depth (h) of the Earth’s surface from h0 = 0 km to h5* = 6370 km that corresponds to the temperature (T) from T = 300 K to T = 7000 K and the pressure (P) from P = 0 GPa to P = 360 GPa, and then annealing time (t) (120 ps) on the heterogeneous kinetics of bulk Fe2O3, such as the Radial Distribution Function (RDF), Coordination Number (CN), angular distribution, number of structural units, size (l), and energy (E). When the temperature increases in the low temperature (T) region at zero pressure (P), the link length (r), RDF height, size, CN, and the number of structural units FeO4, FeO5, and FeO6 do not change significantly, but only the very large change in E serves as the basis for future research on the mechanical properties and electrical conductivity of semiconductor materials. When the depth (h) of the Earth’s surface and the thermal annealing time at different locations are increased, the characteristic quantities of dynamic dynamics change greatly, including the disappearance of FeO4 at depth h1 ≥ 17.5 km and the appearance of additional structural units FeO7, FeO8, and FeO9 at h3 ≥ 1742 km and FeO10 at h5 ≥ 5562.5 km.
This paper studies the influence of factors such as heating rate, atomic number, temperature, and annealing time on the structure and the crystallization process of NiAu alloy. Increasing the heating ...rate leads to the moving process from the crystalline state to the amorphous state; increasing the temperature (T) also leads to a changing process into the liquid state; when the atomic number (N), and t increase, it leads to an increased crystalline process. As a result, the dependence between size (l) and atomic number (N), the total energy of the system (Etot) with N as l~N−1/3, and −Etot always creates a linear function of N, glass temperature (Tg) of the NiAu alloy, which is Tg = 600 K. During the study, the number of the structural units was determined by the Common Neighborhood Analysis (CNA) method, radial distribution function (RDF), size (l), and Etot. The result shows that the influencing factors to the structure of NiAu alloy are considerable.
The composition, structural features, surface morphology, roughness parameters, particle size, and magnetic features of nanostructured Fe‐Co‐Ni deposits manufactured on conducting indium tin ...oxide‐coated glasses at various electrolyte pH values are studied. The deposit produced at low electrolyte pH contains slightly higher Fe and Co contents but lower Ni content compared to deposits fabricated at high pH values. Further composition analysis confirms that the reduction rates of Fe2+ and Co2+ are higher than the Ni2+ reduction rate. The films consist of nano‐sized crystallites with a strong 111 preferred orientation. The results also reveal that the crystallization of the thin films is affected by the electrolyte pH. Surface analysis shows that the deposit surfaces are composed of nano‐sized particles with different diameters. The mean particle diameter and surface roughness decrease as the pH of the electrolyte decreases. The effect of the electrolyte pH on the morphology is also discussed in terms of surface skewness and kurtosis parameters. Magnetic analysis shows that the resultant deposits have in‐plane hysteresis loops with low and close SQR parameters ranging from 0.079 to 0.108. The results also reveal that the coercive field of the deposits increases from 29.4 Oe to 41.3 Oe as the electrolyte pH decreases from 4.7 to 3.2.
LAY DESCRIPTION
The aim of this study is to investigate the impact of the electrolyte pH on the properties of nanostructured Fe‐Co‐Ni/ITO thin films. The chemical composition, structural features and magnetic characteristics of the samples were analyzed through EDX, XRD and VSM, respectively. SEM and AFM methods were used to characterize the surface morphology of the samples. The analysis results showed that the mean particle diameter and surface roughness of the films decreased as the pH of the electrolyte decreased. Besides, lowering the electrolyte pH led to the formation of some pinholes and cracks on the film surface. The change in the surface morphology caused by the pH of the electrolyte and its effect on the magnetic characteristics of the films are discussed in terms of the obtained results.
In this study, to explore the effect of Co contents on the electroplated Fe–Co–Ni samples, three different Fe–Co33–Ni62, Fe–Co43–Ni53, and Fe–Co61–Ni36 samples were electrochemically grown from ...Plating Solutions (PSs) containing different amounts of Co ions on indium tin oxide substrates. Compositional analysis showed that an increase in the Co ion concentration in the PS gives rise to an increment in the weight fraction of Co in the sample. In all samples, the co–deposition characteristic was described as anomalous. The samples exhibited a predominant reflection from the (111) plane of the face–centered cubic structure. However, the Fe–Co61–Ni36 sample also had a weak reflection from the (100) plane of the hexagonal close–packed structure of Co. An enhancement in the Co contents caused a strong decrement in the crystallinity, resulting in a decrease in the size of the crystallites. The Fe–Co33–Ni62 sample exhibited a more compact surface structure comprising only cauliflower–like agglomerates, while the Fe–Co43–Ni53 and Fe–Co61–Ni36 samples had a surface structure consisting of both pyramidal particles and cauliflower–like agglomerates. The results also revealed that different Co contents play an important role in the surface roughness parameters. From the magnetic analysis of the samples, it was understood that the Fe–Co61–Ni36 sample has a higher coercive field and magnetic squareness ratio than the Fe–Co43–Ni53 and Fe–Co33–Ni62 samples. The differences observed in the magnetic characteristics of the samples were attributed to the changes revealed in their phase structure and surface roughness parameters. The obtained results are the basis for the fabrication of future magnetic devices.
All-normal dispersion supercontinuum generation (SG) in a large hollow core photonic crystal fiber (PCF) infiltrated with carbon tetrachloride is studied experimentally. The PCF is optimized to have ...a flat normal dispersion in a broadband range (0.8–1.7 µm) varying from -150 to 0 ps/nm/km. The effective mode area at pump wavelength (λ=1030 nm) is as large as 42.2 µm2 and readily meets the requirements for an all-fiber supercontinuum system. Infiltration of the core with carbon tetrachloride ensures a high nonlinear coefficient of the fiber equal to 22 1/W/km. Using an off-the-shelf 1030 nm fiber laser with 400 fs and 25 nJ input pulses, we generated an all-normal supercontinuum in the 850–1250 nm wavelength range.
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