Dielectric measurement of high-loss liquids in rectangular waveguides

1965 ◽  
Vol 1 (1) ◽  
pp. 4 ◽  
Author(s):  
J.A. Staniforth ◽  
R.G. Bennett ◽  
J.H. Calderwood
Keyword(s):  
Dielectric Measurement ◽  
High Loss ◽  
Rectangular Waveguides

Microstructural characterization of YBaCuO Films on LaAlO3 substrates

1989 ◽  
Vol 47 ◽  
pp. 180-181
Author(s):  
E. L. Hall ◽  
A. Mogro-Campero ◽  
N. Lewis ◽  
L. G. Turner
Keyword(s):  
Dielectric Constant ◽  
Single Crystal ◽  
Film Growth ◽  
Microstructural Characterization ◽  
Lattice Parameter ◽  
Film Plane ◽  
Substrate Material ◽  
High Loss ◽  
Amorphous Substrates ◽  
High Dielectric

There have been a large number of recent studies of the growth of Y-Ba-Cu-O thin films, and these studies have employed a variety of substrates and growth techniques. To date, the highest values of Tc and Jc have been found for films grown by sputtering or coevaporation on single-crystal SrTiO3 substrates, which produces a uniaxially-aligned film with the YBa2Cu3Ox c-axis normal to the film plane. Multilayer growth of films on the same substrate produces a triaxially-aligned film (regions of the film have their c-axis parallel to each of the three substrate <100> directions) with lower values of Jc. Growth of films on a variety of other polycrystalline or amorphous substrates produces randomly-oriented polycrystalline films with low Jc. Although single-crystal SrTiO3 thus produces the best results, this substrate material has a number of undesireable characteristics relative to electronic applications, including very high dielectric constant and a high loss tangent at microwave frequencies. Recently, Simon et al. have shown that LaAlO3 could be used as a substrate for YBaCuO film growth. This substrate is essentially a cubic perovskite with a lattice parameter of 0.3792nm (it has a slight rhombohedral distortion at room temperature) and this material exhibits much lower dielectric constant and microwave loss tangents than SrTiO3. It is also interesting from a film growth standpoint since it has a slightly smaller lattice parameter than YBa2Cu3Ox (a=0.382nm, b=c/3=0.389nm), while SrTiO3 is slightly larger (a=0.3905nm).

Local dielectric measurement by waveguide-type microscopic aperture probe

PIERS Online ◽  
2006 ◽  
Vol 2 (1) ◽  
pp. 13-14 ◽  
Author(s):  
Toshitatsu Suzuki ◽  
Kenichi Sugimoto ◽  
Yuki Yamagami ◽  
Tadahiro Negishi ◽  
Yasuo Watanabe
Keyword(s):  
Dielectric Measurement ◽  
Waveguide Type

scholarly journals Graphene Nanoribbon Gap Waveguides for Dispersionless and Low-Loss Propagation with Deep-Subwavelength Confinement

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1302
Author(s):  
Zhiyong Wu ◽  
Lei Zhang ◽  
Tingyin Ning ◽  
Hong Su ◽  
Irene Ling Li ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Potential ◽  
Shape Change ◽  
Optical Switch ◽  
Pulse Amplitude ◽  
Propagation Distance ◽  
Graphene Nanoribbon ◽  
Low Loss ◽  
High Loss ◽  
On Chip

Surface plasmon polaritons (SPPs) have been attracting considerable attention owing to their unique capabilities of manipulating light. However, the intractable dispersion and high loss are two major obstacles for attaining high-performance plasmonic devices. Here, a graphene nanoribbon gap waveguide (GNRGW) is proposed for guiding dispersionless gap SPPs (GSPPs) with deep-subwavelength confinement and low loss. An analytical model is developed to analyze the GSPPs, in which a reflection phase shift is employed to successfully deal with the influence caused by the boundaries of the graphene nanoribbon (GNR). It is demonstrated that a pulse with a 4 μm bandwidth and a 10 nm mode width can propagate in the linear passive system without waveform distortion, which is very robust against the shape change of the GNR. The decrease in the pulse amplitude is only 10% for a propagation distance of 1 μm. Furthermore, an array consisting of several GNRGWs is employed as a multichannel optical switch. When the separation is larger than 40 nm, each channel can be controlled independently by tuning the chemical potential of the corresponding GNR. The proposed GNRGW may raise great interest in studying dispersionless and low-loss nanophotonic devices, with potential applications in the distortionless transmission of nanoscale signals, electro-optic nanocircuits, and high-density on-chip communications.

scholarly journals Plasmonic hot-electron photodetection with quasi-bound states in the continuum and guided resonances

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenhao Wang ◽  
Lucas V. Besteiro ◽  
Peng Yu ◽  
Feng Lin ◽  
Alexander O. Govorov ◽  
...  
Keyword(s):  
Bound States ◽  
Structural Parameters ◽  
Hybrid Structure ◽  
Fine Tuning ◽  
Hot Electrons ◽  
Hot Electron ◽  
Perfect Absorption ◽  
High Loss ◽  
Guided Mode ◽  
The Continuum

Abstract Hot electrons generated in metallic nanostructures have shown promising perspectives for photodetection. This has prompted efforts to enhance the absorption of photons by metals. However, most strategies require fine-tuning of the geometric parameters to achieve perfect absorption, accompanied by the demanding fabrications. Here, we theoretically propose a Ag grating/TiO2 cladding hybrid structure for hot electron photodetection (HEPD) by combining quasi-bound states in the continuum (BIC) and plasmonic hot electrons. Enabled by quasi-BIC, perfect absorption can be readily achieved and it is robust against the change of several structural parameters due to the topological nature of BIC. Also, we show that the guided mode can be folded into the light cone by introducing a disturbance to become a guided resonance, which then gives rise to a narrow-band HEPD that is difficult to be achieved in the high loss gold plasmonics. Combining the quasi-BIC and the guided resonance, we also realize a multiband HEPD with near-perfect absorption. Our work suggests new routes to enhance the light-harvesting in plasmonic nanosystems.

scholarly journals Amplification characteristics in active tapered segmented cladding fiber with large mode area

2021 ◽  
Vol 9 ◽  
Author(s):  
Caijian Xie ◽  
Tigang Ning ◽  
Jingjing Zheng ◽  
Li Pei ◽  
Jianshuai Wang ◽  
...  
Keyword(s):  
High Power ◽  
Heat Load ◽  
Nonlinear Effects ◽  
Single Mode ◽  
Large Mode Area ◽  
High Loss ◽  
Effective Mode Area ◽  
Steady State Rate ◽  
State Rate ◽  
Mode Area

Abstract A kind of tapered segmented cladding fiber (T-SCF) with large mode area (LMA) is proposed, and the mode and amplification characteristics of T-SCFs with concave, linear, and convex tapered structures are investigated based on finite-element method (FEM) and few-mode steady-state rate equation. Simulation results indicate that the concave tapered structure can introduce high loss for high-order modes (HOMs) that is advantageous to achieve single-mode operation, whereas the convex tapered structure provides large effective mode area that can help to mitigate nonlinear effects. Meanwhile, the small-to-large amplification scheme shows further advantages on stripping off HOMs, and the large-to-small amplification scheme decreases the heat load density induced by the high-power pump. Moreover, single-mode propagation performance, effective mode area, and heat load density of the T-SCF are superior to those of tapered step index fiber (T-SIF). These theoretical model and numerical results can provide instructive suggestions for designing high-power fiber lasers and amplifiers.

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