Unveiling electrically tunable characteristics of second-order dispersion in graphene-silicon nitride waveguides

2019 ◽  
Vol 33 (05) ◽  
pp. 1950053 ◽  
Author(s):  
Peng Xie ◽  
Mantian Xue ◽  
Yu Wen ◽  
Xiaofeng Li ◽  
Xinyu Wang ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Graphene Layer ◽  
Optoelectronic Devices ◽  
Second Order ◽  
Core Material ◽  
The Core ◽  
Large Bandwidth ◽  
Waveguide Model ◽  
Potential Applications ◽  
Order Dispersion

In this paper, we proposed a graphene-silicon nitride (GSN) waveguide model, which was unveiled to unveil its second-order dispersion (SOD) characteristics. The influences of the different thicknesses of graphene layer and the different heights from graphene to the core material of silicon nitride on SOD were investigated in detail. The tunability of SOD via controlling the bias voltage applied to the graphene layer was demonstrated and a 50 nm wavelength tuning was achieved with a small perturbation in voltage while keeping the geometric structure of the waveguide unchanged. Moreover, a flat SOD curve of the GSN waveguide was obtained with a large bandwidth of 700 nm between the two zero-dispersion wavelengths (ZDWs). These results provided significant insights for potential applications of graphene-related optoelectronic devices, integrated optics, and optical communications.

Influences of second-order and third-order dispersion on spectral properties of mid-infrared wavelength conversion in silicon nitride waveguides

2019 ◽  
Vol 33 (21) ◽  
pp. 1950241
Author(s):  
Peng Xie ◽  
Jiarui Liu ◽  
Yu Wen ◽  
Zishen Wan ◽  
Yishan Wang
Keyword(s):  
Silicon Nitride ◽  
Spectral Properties ◽  
Wavelength Conversion ◽  
Infrared Region ◽  
Phase Match ◽  
Second Order ◽  
Third Order ◽  
Mid Infrared ◽  
Third Order Dispersion ◽  
Order Dispersion

The influences of second-order dispersion (SOD) and third-order dispersion (TOD) on spectral properties of wavelength conversion based on FWM at mid-infrared region (mid-IR) are theoretically investigated in a silicon nitride waveguide. It is found that the SOD and TOD can affect the frequency shift and temporal profiles of idler pulses. Moreover, the temporal and frequency spectrum of output signal are also discussed with different SODs and TODs. Meanwhile, the numerical simulation results imply that the efficiency of FWM process will be reduced and the wavelength range of phase-match will be shifted due to the change of SOD or TOD.

Theoretical investigation of nano-photonic graphene-based waveguide

2020 ◽  
Vol 34 (31) ◽  
pp. 2050350
Author(s):  
Yupeng Wang ◽  
Yawen Xiao ◽  
Luning Wang ◽  
Haichen Rong ◽  
Xin Li ◽  
...  
Keyword(s):  
Graphene Layer ◽  
Electric Field Distribution ◽  
The Other ◽  
Core Material ◽  
Physical Mechanisms ◽  
The Core ◽  
Vertical Slot ◽  
Photoelectronic Device ◽  
Simulation Results ◽  
Slot Structure

This paper reports two design thoughts about nano-scale waveguides including parallel slot structure and vertical slot structure. According to the simulation results of different schemes, the design of parallel slot structure is demonstrated to exhibit better performance. Thus, we further explore its typical characteristics based on this scheme, such as electric field distribution, effective refractive index, non-linearity, dispersion and so on. Besides, we explore the properties of the waveguide under different thicknesses of the core material. On the other hand, combining with graphene layer applied to additional bias voltage, the tunable properties of the waveguide are realized. These results can provide significant reference for photoelectronic device field and lead to a deeper insight of the physical mechanisms of graphene-based waveguides.

scholarly journals Acoustic Panels Made of Paper Sludge and Clay Composites

2021 ◽  
Vol 13 (2) ◽  
pp. 637
Author(s):  
Tomas Astrauskas ◽  
Tomas Januševičius ◽  
Raimondas Grubliauskas
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Composite Panel ◽  
Sound Absorption Coefficient ◽  
Core Material ◽  
Paper Sludge ◽  
Frequency Range ◽  
Absorption Properties ◽  
Air Gaps ◽  
The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

scholarly journals Iron Based Core-Shell Structures as Versatile Materials: Magnetic Support and Solid Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 72
Author(s):  
Christian Zambrzycki ◽  
Runbang Shao ◽  
Archismita Misra ◽  
Carsten Streb ◽  
Ulrich Herr ◽  
...  
Keyword(s):  
Water Purification ◽  
Functional Materials ◽  
Core Material ◽  
Solid Catalyst ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
The Core ◽  
Shell Nanostructures ◽  
Sio2 Shell ◽  
Iron Based

Core-shell materials are promising functional materials for fundamental research and industrial application, as their properties can be adapted for specific applications. In particular, particles featuring iron or iron oxide as core material are relevant since they combine magnetic and catalytic properties. The addition of an SiO2 shell around the core particles introduces additional design aspects, such as a pore structure and surface functionalization. Herein, we describe the synthesis and application of iron-based core-shell nanoparticles for two different fields of research that is heterogeneous catalysis and water purification. The iron-based core shell materials were characterized by transmission electron microscopy, as well as N2-physisorption, X-ray diffraction, and vibrating-sample magnetometer measurements in order to correlate their properties with the performance in the target applications. Investigations of these materials in CO2 hydrogenation and water purification show their versatility and applicability in different fields of research and application, after suitable individual functionalization of the core-shell precursor. For design and application of magnetically separable particles, the SiO2 shell is surface-functionalized with an ionic liquid in order to bind water pollutants selectively. The core requires no functionalization, as it provides suitable magnetic properties in the as-made state. For catalytic application in synthesis gas reactions, the SiO2-stabilized core nanoparticles are reductively functionalized to provide the catalytically active metallic iron sites. Therefore, Fe@SiO2 core-shell nanostructures are shown to provide platform materials for various fields of application, after a specific functionalization.

scholarly journals nanocrystals (0 ≤ x ≤ 1): growth, size control and shell formation on β-NaCeF4:Tb core particles

CrystEngComm ◽  
2020 ◽  
Vol 22 (46) ◽  
pp. 8036-8044
Author(s):  
Jannis Wehmeier ◽  
Markus Haase
Keyword(s):  
Size Control ◽  
Lattice Parameters ◽  
Core Material ◽  
Shell Formation ◽  
Shell Material ◽  
Strontium Content ◽  
The Core ◽  
Lighter Lanthanides ◽  
Core Particles

is an interesting shell material for β-NaREF4 particles of the lighter lanthanides (RE = Ce, Pr, Nd), as variation of its strontium content x allows to vary its lattice parameters and match those of the core material.

SHELL MATERIAL'S PERFORMANCE OF THE MICROCAPSULE FOR ELECTROLYTIC CO-DEPOSITION

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3124-3130 ◽  
Author(s):  
HUI CONG LIU ◽  
XIU QING XU ◽  
WEI PING LI ◽  
YAN HONG GUO ◽  
LI-QUN ZHU
Keyword(s):  
Composite Coating ◽  
Methyl Cellulose ◽  
Water Vapor Permeability ◽  
Core Material ◽  
Vapor Permeability ◽  
Shell Material ◽  
The Core ◽  
Surface Performance ◽  
The Stability ◽  
Positive Effect

The shell material of microcapsules has an important effect on the electrolytic co-deposition behavior, the release of core material and the surface performance of composite coating. This paper discussed the tensile property and the stability of three shell materials including polyvinyl alcohol (PVA), gelatin and methyl cellulose (MC). It is found that these three shell materials have good mechanical strength and flexibility which are favorable to electrolytic co-deposition and stability of microcapsules in composite coating and that MC has well permeability and porosity which has a positive effect on the release of the core material in composite coating. Moreover, the study of the thermal properties and water vapor permeability of the three shell materials showed that their permeability improved with increase of temperature and humidity. In addition, the composite copper coating containing microcapsules with PVA, gelatin or MC as shell material was prepared respectively.

Damage behavior of potting materials in sandwich composites with pinned joints

2015 ◽  
Vol 22 (5) ◽  
Author(s):  
Cesim Atas ◽  
Alper Basmaci
Keyword(s):  
Core Material ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Sandwich Composites ◽  
Resin Infusion ◽  
Damage Behavior ◽  
Mechanical Joints ◽  
The Core ◽  
Bottom Face ◽  
Infusion Technique

AbstractThe damage behavior of the potting materials around a pinhole, being used in the mechanical joints of sandwich composites, is investigated experimentally. The sandwich composite panels used in the tests were manufactured by the vacuum-assisted resin infusion technique. Each of the top and bottom face sheets of the panels consisted of two woven E-glass/epoxy layers. As the core material, PVC foam (AIREX

Comparison of P- and As-core-modified porphyrins with the parental porphyrin: a computational study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Aleksey E. Kuznetsov
Keyword(s):  
Computational Study ◽  
Electron Delocalization ◽  
Energy Structure ◽  
Frontier Molecular Orbitals ◽  
The Core ◽  
Potential Applications ◽  
Noticeable Reduction ◽  
Internal Electron ◽  
Porphyrin Core ◽  
Homo Lumo

Abstract The first comparative DFT (B3LYP/6-31G*) study of the Zn-porphyrin and its two derivatives, ZnP(P)4 and ZnP(As)4, is reported. For all three species studied, ZnP, ZnP(P)4 and ZnP(As)4, the singlet was calculated to be the lowest-energy structure and singlet-triplet gap was found to decrease from ca. 41—42 kcal/mol for N to ca. 17—18 kcal/mol for P and to ca. 10 kcal/mol for As. Both ZnP(P)4 and ZnP(As)4 were calculated to attain very pronounced bowl-like shapes. The frontier molecular orbitals (MOs) of the core-modified porphyrins are quite similar to the ZnP frontier MOs. For the HOMO-2 of the core-modified porphyrins due to the ZnP(P)4/ZnP(As)4 bowl-like shapes we might suppose the existence of “internal” electron delocalization inside the ZnP(P)4/ZnP(As)4 “bowls”. Noticeable reduction of the HOMO/LUMO gaps was calculated for ZnP(P)4 and ZnP(As)4, by ca. 1.10 and 1.47 eV, respectively, compared to ZnP. The core-modification of porphyrins by P and especially by As was found to result in significant decrease of the charge on Zn-centers, by ca. 0.61—0.67e for P and by ca. 0.69—0.76e for As. Charges on P- and As-centers were computed to have large positive values, ca. 0.41—0.45e and ca. 0.43—0.47e, for P and As, respectively, compared to significant negative values, ca. −0.65 to −0.66e for N. The porphyrin core-modification by heavier N congeners, P and As, can noticeably modify the structures, electronic, and optical properties of porphyrins, thus affecting their reactivity and potential applications.

Release Profile of a Model Protein Drug Depending on the Stability of Microspheres Based on Polyelectrolyte Complex

2007 ◽  
Vol 342-343 ◽  
pp. 505-508
Author(s):  
Sung Won Kim ◽  
Yun Sik Nam ◽  
Yeon Jin Min ◽  
Jong Ho Kim ◽  
Kwang Meyong Kim ◽  
...  
Keyword(s):  
Polyelectrolyte Complex ◽  
Coating Layer ◽  
Great Influence ◽  
Release Profile ◽  
Core Material ◽  
Glycol Chitosan ◽  
The Core ◽  
Key Factor ◽  
Model Protein ◽  
The Stability

Stability and disintegration of natural polyelectrolyte complex microspheres for protein drugs delivery have been extensively investigated because of their great influence on the drug release patterns. In this study, we tested stability of microspheres with alginate (Alg) core layered by either chitosan (Chi) or glycol chitosan (GChi) by examining release profiles of fluorophorelabeled bovine serum albumin (BSA) and lysozyme (Lys) from the microspheres. While GChi shell was disintegrated quickly, Chi-shell microspheres showed good stability in PBS. Disintegration of the coated layer induced the core material instable. The results indicated that while the charges of the shell material provided additional diffusion barrier against the protein release, the key factor to hold the proteins inside the microspheres was the integrity of the outer coating layer.

Sign in / Sign up

Export Citation Format

Share Document