scholarly journals Tunable Plasmonic Talbot Effect Based on Graphene Monolayer

2020 ◽  
Vol 10 (14) ◽  
pp. 4782
Author(s):  
Huanxi Ma ◽  
Shaojian Su ◽  
Hengjie Zhou ◽  
Zeyang Zhao ◽  
Zhili Lin ◽  
...  
Keyword(s):  
Chemical Potential ◽  
Graphene Monolayer ◽  
Talbot Effect ◽  
Full Width ◽  
Half Maximum ◽  
New Approach ◽  
Talbot Distance ◽  
Wavelength Scale ◽  
Plasmon Polaritons ◽  
Sub Wavelength

In this article, the plasmonic Talbot effect supported by a graphene monolayer is investigated theoretically when surface plasmon polaritons (SPPs) are excited on the graphene. The Talbot effect distance is studied by varying the chemical potential, wavelength and the period of grating. The Talbot distance increases with the period in a parabolic way, and exhibits the opposite trends with respect to the chemical potential and wavelength. Moreover, the full width at half maximum (FWHM) of the Talbot image is recorded as a function of chemical potential and the wavelength. This study provides a new approach for sub-wavelength scale imaging and extends the applications of Talbot effect as well as graphene-based plasmonic devices.

scholarly journals Хлорид-гидридная газофазная эпитаксия полуполярного слоя AlN(1012) на наноструктурированной подложке Si(100)

2020 ◽  
Vol 46 (2) ◽  
pp. 12
Author(s):  
В.Н. Бессолов ◽  
М.Е. Компан ◽  
Е.В. Коненкова ◽  
В.Н. Пантелеев
Keyword(s):  
Hydride Vapor Phase Epitaxy ◽  
Full Width ◽  
Half Maximum ◽  
X Ray Diffraction ◽  
Inclined Plane ◽  
New Approach ◽  
Rocking Curve ◽  
X Ray ◽  
Patterned Substrate ◽  
Maximum Value

A new approach is proposed to the synthesis of a semipolar AlN on a Si(100) substrate at the surface for which the angle between the inclined plane of the nanogrooves and Si(100) is 47°. It is shown that the hydride vapor-phase epitaxy on a such nano-patterned substrate enables formation of a semipolar layer AlN (1012) characterized by the full width at half maximum value as low as ωθ ~60 arcmin for the x-ray diffraction rocking curve. It is found that the Raman spectra of the semipolar AlN(10-12) layer contain additional peaks on the Raman curves associated with phonons A1(TO) and E1(TO), in contrast to the polar AlN(0001) layer, where the peak A1(LO) is additionally manifested.

scholarly journals Generation of optical needle and dark channel by tight focusing of radially polarized circular partially coherent beams

2020 ◽  
Vol 50 (2) ◽  
Author(s):  
Huichuan Lin ◽  
Yan Li ◽  
Xiaoming Zhou ◽  
Juanjuan Wang ◽  
Ziyang Chen ◽  
...  
Keyword(s):  
Numerical Aperture ◽  
Full Width ◽  
Half Maximum ◽  
High Numerical Aperture ◽  
Partially Coherent ◽  
Dark Channel ◽  
Tight Focusing ◽  
Coherent Beams ◽  
Radially Polarized ◽  
Sub Wavelength

We theoretically investigate the tight focusing of radially polarized circular partially coherent (RPCPC) beams through a high numerical aperture objective. The sub-wavelength super-long optical needle and dark channel can be obtained near the focus, by engineering the source coherent length of the incident RPCPC beams. The length of the optical needle and the dark channel can be adjusted, and the obtained maximal lengths of the optical needle and the dark channel are both 22λ. The full width at half maximum of the optical needle and the dark channel are 0.6λ and 0.48λ, respectively.

scholarly journals Observing and controlling a Tamm plasmon at the interface with a metasurface

Nanophotonics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 897-903 ◽  
Author(s):  
Oleksandr Buchnev ◽  
Alexandr Belosludtsev ◽  
Victor Reshetnyak ◽  
Dean R. Evans ◽  
Vassili A. Fedotov
Keyword(s):  
Liquid Crystal ◽  
Metal Film ◽  
Near Infrared ◽  
Thin Metal Film ◽  
Outer Side ◽  
Spectral Position ◽  
External Perturbations ◽  
Dielectric Mirror ◽  
Wavelength Scale ◽  
Sub Wavelength

AbstractWe demonstrate experimentally that Tamm plasmons in the near infrared can be supported by a dielectric mirror interfaced with a metasurface, a discontinuous thin metal film periodically patterned on the sub-wavelength scale. More crucially, not only do Tamm plasmons survive the nanopatterning of the metal film but they also become sensitive to external perturbations as a result. In particular, by depositing a nematic liquid crystal on the outer side of the metasurface, we were able to red shift the spectral position of Tamm plasmon by 35 nm, while electrical switching of the liquid crystal enabled us to tune the wavelength of this notoriously inert excitation within a 10-nm range.

scholarly journals Ultra-high-Q resonances in plasmonic metasurfaces

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Saad Bin-Alam ◽  
Orad Reshef ◽  
Yaryna Mamchur ◽  
M. Zahirul Alam ◽  
Graham Carlow ◽  
...  
Keyword(s):  
Incident Light ◽  
Reducing Power ◽  
Field Enhancement ◽  
Plasmonic Nanostructures ◽  
High Q ◽  
Alternative Material ◽  
Order Of Magnitude ◽  
Wavelength Scale ◽  
Strong Confinement ◽  
Sub Wavelength

AbstractPlasmonic nanostructures hold promise for the realization of ultra-thin sub-wavelength devices, reducing power operating thresholds and enabling nonlinear optical functionality in metasurfaces. However, this promise is substantially undercut by absorption introduced by resistive losses, causing the metasurface community to turn away from plasmonics in favour of alternative material platforms (e.g., dielectrics) that provide weaker field enhancement, but more tolerable losses. Here, we report a plasmonic metasurface with a quality-factor (Q-factor) of 2340 in the telecommunication C band by exploiting surface lattice resonances (SLRs), exceeding the record by an order of magnitude. Additionally, we show that SLRs retain many of the same benefits as localized plasmonic resonances, such as field enhancement and strong confinement of light along the metal surface. Our results demonstrate that SLRs provide an exciting and unexplored method to tailor incident light fields, and could pave the way to flexible wavelength-scale devices for any optical resonating application.

scholarly journals Spectroscopic Studies of Laser-Based Far-Ultraviolet Plasma Light Source

2021 ◽  
Vol 11 (15) ◽  
pp. 6919
Author(s):  
Majid Masnavi ◽  
Martin Richardson
Keyword(s):  
Dense Plasma ◽  
Wavelength Region ◽  
Spectroscopic Studies ◽  
Radiation Hydrodynamics ◽  
Full Width ◽  
Half Maximum ◽  
Laser Plasmas ◽  
Series Of Experiments ◽  
Far Ultraviolet ◽  
Radiation Conversion

A series of experiments is described which were conducted to measure the absolute spectral irradiances of laser plasmas created from metal targets over the wavelength region of 123–164 nm by two separate 1.0 μm lasers, i.e., using 100 Hz, 10 ns, 2–20 kHz, 60–100 ns full-width-at-half-maximum pulses. A maximum radiation conversion efficiency of ≈ 3%/2πsr is measured over a wavelength region from ≈ 125 to 160 nm. A developed collisional-radiative solver and radiation-hydrodynamics simulations in comparison to the spectra detected by the Seya–Namioka-type monochromator reveal the strong broadband experimental radiations which mainly originate from bound–bound transitions of low-ionized charges superimposed on a strong continuum from a dense plasma with an electron temperature of less than 10 eV.

scholarly journals Experimental nanofocusing of surface plasmon polaritons using a gravitational field

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3279-3285 ◽  
Author(s):  
Zhiwei Yan ◽  
Chong Sheng ◽  
Shining Zhu ◽  
Hui Liu
Keyword(s):  
Gravitational Field ◽  
Surface Plasmon ◽  
Surface Plasmon Polaritons ◽  
Simple Structure ◽  
Spatial Scales ◽  
Optical Process ◽  
Design Structure ◽  
Nonlinear Optical Process ◽  
Plasmon Polaritons ◽  
Sub Wavelength

AbstractHow to capture electromagnetic fields into sub-wavelength spatial scales has been a major challenge in nanophotonics, especially confining surface plasmon polaritons into regions as small as a few nanometers. Although various methods are proposed to achieve this goal, these methods require complex fabrication process. Here, we demonstrate experimentally the achievement of nanofocusing of surface plasmon polaritons with an intensity enhancement of three, using the simple structure with just pasting a sliver microwire on a sliver layer. And the designed structure has a well-defined gravitational field inspired by transformation optics. This simple design structure has applications to enhance light–matter interactions, such as nonlinear optical process and Raman scattering.

scholarly journals Time to peak and full width at half maximum in MR perfusion: valuable indicators for monitoring moyamoya patients after revascularization

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adam Huang ◽  
Chung-Wei Lee ◽  
Hon-Man Liu
Keyword(s):  
Study Data ◽  
Unknown Etiology ◽  
Dynamic Susceptibility ◽  
Full Width ◽  
Half Maximum ◽  
Mr Perfusion ◽  
Dynamic Susceptibility Contrast ◽  
Time To Peak ◽  
Mr Perfusion Imaging ◽  
Outcome Monitoring

AbstractMoyamoya disease (MMD) is a chronic, steno-occlusive cerebrovascular disorder of unknown etiology. Surgical treatment is the only known effective method to restore blood flow to affected areas of the brain. However, there are lack of generally accepted noninvasive tools for therapeutic outcome monitoring. As dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) is the standard MR perfusion imaging technique in the clinical setting, we investigated a dataset of nineteen pediatric MMD patients with one preoperational and multiple periodic DSC MRI examinations for four to thirty-eight months after indirect revascularization. A rigid gamma variate model was used to derive two nondeconvolution-based perfusion parameters: time to peak (TTP) and full width at half maximum (FWHM) for monitoring transitional bolus delay and dispersion changes respectively. TTP and FWHM values were normalized to the cerebellum. Here, we report that 74% (14/19) of patients improve in both TTP and FWHM measurements, and whereof 57% (8/14) improve more noticeably on FWHM. TTP is in good agreement with Tmax in estimating bolus delay. Our study data also suggest bolus dispersion estimated by FWHM is an additional, informative indicator in pediatric MMD monitoring.

Quasi-Talbot effect of the sub-wavelength Ag grating

2010 ◽  
Vol 283 (24) ◽  
pp. 5231-5235 ◽  
Author(s):  
Xia Wan ◽  
Qingkang Wang ◽  
Haihua Tao
Keyword(s):  
Talbot Effect ◽  
Sub Wavelength

Preparation of highly c-axis oriented AlN thin films on Hastelloy tapes with Y2O3 buffer layer for flexible SAW sensor applications

2016 ◽  
Vol 09 (02) ◽  
pp. 1650023 ◽  
Author(s):  
Bin Peng ◽  
Jianying Jiang ◽  
Guo Chen ◽  
Lin Shu ◽  
Jie Feng ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Smooth Surface ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Mean Square ◽  
Full Width ◽  
Half Maximum ◽  
Sensor Applications ◽  
Saw Sensor ◽  
Y2o3 Buffer Layer

Highly c-axis oriented aluminum nitrade (AlN) films were successfully deposited on flexible Hastelloy tapes by middle-frequency magnetron sputtering. The microstructure and piezoelectric properties of the AlN films were investigated. The results show that the AlN films deposited directly on the bare Hastelloy substrate have rough surface with root mean square (RMS) roughness of 32.43[Formula: see text]nm and its full width at half maximum (FWHM) of the AlN (0002) peak is [Formula: see text]. However, the AlN films deposited on the Hastelloy substrate with Y2O3 buffer layer show smooth surface with RMS roughness of 5.46[Formula: see text]nm and its FWHM of the AlN (0002) peak is only [Formula: see text]. The piezoelectric coefficient d[Formula: see text] of the AlN films deposited on the Y2O3/Hastelloy substrate is larger than three times that of the AlN films deposited on the bare Hastelloy substrate. The prepared highly c-axis oriented AlN films can be used to develop high-temperature flexible SAW sensors.

scholarly journals Research of the anti-resonance pulse forming network and its application in the Marx generator

2016 ◽  
Vol 34 (4) ◽  
pp. 675-686 ◽  
Author(s):  
Z.-L. Pan ◽  
J.-H. Yang ◽  
X.-B. Cheng
Keyword(s):  
Equivalent Circuit ◽  
Rise Time ◽  
Pulse Width ◽  
Marx Generator ◽  
Full Width ◽  
Half Maximum ◽  
Compact Structure ◽  
Fall Time ◽  
Pulse Forming Network ◽  
Load Pulse

AbstractAn anti-resonance pulse forming network (PFN) has been designed, analyzed, and tested for its application in generating quasi-square pulses. According to the circuit simulations, a compact generator based on two/three-section network was constructed. Two-section network is applied in the generator due to its compact structure, while three-section network is employed for generating pulses with higher quality. When two-section network is applied in the generator, the full-width at half-maximum of the load pulse is 400 ns, at the same time, its rise time, flat top and fall time are 90, 180 and 217 ns, respectively. When the three-section network is applied with the same pulse width of the load pulse, the rise time of the output decreases to 60 ns, while the flat top increases to 240 ns and the fall time reduces to 109 ns. Meanwhile, this kind of network could be used to shape the output pulses of generators whose equivalent circuit is LC series discharge network, such as MARX generator, into quasi-square pulses. And the preliminary experiment demonstrates that anti-resonance network could work well on four-stage Marx generators. A sine pulse generated by the four-stage Marx generator is shaped into a quasi-square pulse with voltage of 11.8 kV and pulse width about 110 ns based on two-section anti-resonance network.

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