Photon tunneling and transmittance through composite layers of negative- and positive-index media with sinusoidal interface

2020 ◽  
Author(s):  
Li Jiaqi ◽  
Zhang Xiaobao ◽  
Jin Shilong ◽  
Wang Guochen
Keyword(s):  
Photon Tunneling ◽  
Composite Layers ◽  
Positive Index

Energy Transmission by Photon Tunneling in Multilayer Structures Including Negative Index Materials

2005 ◽  
Vol 127 (9) ◽  
pp. 1046-1052 ◽  
Author(s):  
C. J. Fu ◽  
Z. M. Zhang ◽  
D. B. Tanner
Keyword(s):  
Radiative Transfer ◽  
Near Field ◽  
Multilayer Structures ◽  
Negative Index ◽  
Material Loss ◽  
Surface Polaritons ◽  
Negative Index Materials ◽  
Photon Tunneling ◽  
Energy Conversion Devices ◽  
Positive Index

The phenomenon of photon tunneling, which depends on evanescent waves for radiative transfer, has important applications in microscale energy conversion devices and near-field optical microscopy. In recent years, there has been a surge of interest in the so-called negative index materials (NIMs), which have simultaneously negative electric permittivity and negative magnetic permeability. The present work investigates photon tunneling in multilayer structures consisting of positive index materials (PIMs) and NIMs. Some features, such as the enhancement of radiative transfer by the excitation of surface polaritons for both polarizations, are observed in the predicted transmittance spectra. The influence of the number of layers on the transmittance is also examined. The results suggest that the enhanced tunneling transmittance by polaritons also depends on the NIM layer thickness and that subdividing the PIM/NIM layers to enhance polariton coupling can reduce the effect of material loss on the tunneling transmittance.

scholarly journals Low-Temperature Mineralisation of Titania-Siloxane Composite Layers

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 50
Author(s):  
Tomáš Svoboda ◽  
Michal Veselý ◽  
Radim Bartoš ◽  
Tomáš Homola ◽  
Petr Dzik
Keyword(s):  
Low Temperature ◽  
Great Influence ◽  
Gel Permeation Chromatography ◽  
Photocatalytic Decomposition ◽  
Acid Orange 7 ◽  
Composite Layers ◽  
Nonthermal Treatment ◽  
Plasma Methods ◽  
Voltammetric Measurements ◽  
Thermally Treated

This paper deals with low-temperature mineralisation of coatings made with titania-siloxane compositions (TSC). Methyltriethoxysilane has been adopted as the precursor for the siloxane, and during its synthesis, an oligomeric siloxane condensate with methyl moieties acting as TiO2 binder has been produced. These methyl moieties, contained in TSC, provide solubility and prevent gelling, but reduce the hydrophilicity of the system, reduce the transfer of electrons and holes generated in the TiO2. In order to avoid these unfavourable effects, TSC mineralisation can be achieved by nonthermal treatment, for example, by using UV-radiation or plasma treatment. Characterisation of the siloxane was performed by gel permeation chromatography (GPC), which showed the size of the siloxane chain. Thermogravimetric analysis revealed a temperature at which the siloxane mineralises to SiO2. Printed layers of two types of TSC with different siloxane contents were studied by a scanning electron microscope (SEM), where a difference in the porosity of the samples was observed. TSC on fluorine-doped tin oxide (FTO) coated glass and microscopic glass were treated with non-thermal UV and plasma methods. TSC on FTO glass were tested by voltammetric measurements, which showed that the non-thermally treated layers have better properties and the amount of siloxane in the TSC has a great influence on their efficiency. Samples on microscopic glass were subjected to a photocatalytic decomposition test of the model pollutant Acid orange 7 (AO7). Non-thermally treated samples show higher photocatalytic activity than the raw sample.

scholarly journals Tuberculosis contact investigation results among paediatric contacts in low-incidence settings in Finland

2021 ◽  
Author(s):  
Antti Kontturi ◽  
Satu Kekomäki ◽  
Eeva Ruotsalainen ◽  
Eeva Salo
Keyword(s):  
Early Diagnosis ◽  
Young Children ◽  
Large Scale ◽  
Index Case ◽  
Contact Tracing ◽  
Sputum Smear ◽  
Endemic Country ◽  
Household Contacts ◽  
Contact Investigation ◽  
Positive Index

AbstractTuberculosis (TB) risk is highest immediately after primary infection, and young children are vulnerable to rapid and severe TB disease. Contact tracing should identify infected children rapidly and simultaneously target resources effectively. We conducted a retrospective review of the paediatric TB contact tracing results in the Hospital District of Helsinki and Uusimaa from 2012 to 2016 and identified risk factors for TB disease or infection. Altogether, 121 index cases had 526 paediatric contacts of whom 34 were diagnosed with TB disease or infection. The maximum delay until first contact investigation visit among the household contacts under 5 years of age with either TB disease or infection was 7 days. The yield for TB disease or infection was 4.6% and 12.8% for household contacts, 0.5% and 0% for contacts exposed in a congregate setting and 1.4% and 5.0% for other contacts, respectively. Contacts born in a TB endemic country (aOR 3.07, 95% CI 1.10–8.57), with household exposure (aOR 2.96, 95% CI 1.33–6.58) or a sputum smear positive index case (aOR 3.96, 95% CI 1.20–13.03) were more likely to have TB disease or infection.Conclusions: Prompt TB investigations and early diagnosis can be achieved with a well-organised contact tracing structure. The risk for TB infection or disease was higher among contacts with household exposure, a sputum smear positive index case or born in a TB endemic country. Large-scale investigations among children exposed in congregate settings can result in a very low yield and should be cautiously targeted. What is Known:• Vulnerable young children are a high priority in contact tracing and should be evaluated as soon as possible after TB exposure What is New:• Prompt investigations for paediatric TB contacts and early diagnosis of infected children can be achieved with a well-organised contact tracing structure• Large-scale investigations among children exposed in congregate settings can result in a very low yield and should be cautiously targeted

The effect of nanoparticle additive on surface milling in glass fiber reinforced composite structures

2021 ◽  
pp. 096739112110141
Author(s):  
Ferhat Ceritbinmez ◽  
Ahmet Yapici ◽  
Erdoğan Kanca
Keyword(s):  
Composite Materials ◽  
Glass Fiber ◽  
Composite Structures ◽  
Fiber Composite ◽  
Cutting Speed ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Glass Fiber Reinforced ◽  
Composite Layers

In this study, the effect of adding nanosize additive to glass fiber reinforced composite plates on mechanical properties and surface milling was investigated. In the light of the investigations, with the addition of MWCNTs additive in the composite production, the strength of the material has been changed and the more durable composite materials have been obtained. Slots were opened with different cutting speed and feed rate parameters to the composite layers. Surface roughness of the composite layers and slot size were examined and also abrasions of cutting tools used in cutting process were determined. It was observed that the addition of nanoparticles to the laminated glass fiber composite materials played an effective role in the strength of the material and caused cutting tool wear.

scholarly journals Comparing resonant photon tunneling via cavity modes and Tamm plasmon polariton modes in metal-coated Bragg mirrors

2012 ◽  
Vol 37 (19) ◽  
pp. 4026 ◽  
Author(s):  
K. Leosson ◽  
S. Shayestehaminzadeh ◽  
T. K. Tryggvason ◽  
A. Kossoy ◽  
B. Agnarsson ◽  
...  
Keyword(s):  
Photon Tunneling ◽  
Cavity Modes ◽  
Plasmon Polariton

scholarly journals Bianisotropic metasurfaces: physics and applications

Nanophotonics ◽  
2018 ◽  
Vol 7 (6) ◽  
pp. 1069-1094 ◽  
Author(s):  
Viktar S. Asadchy ◽  
Ana Díaz-Rubio ◽  
Sergei A. Tretyakov
Keyword(s):  
State Of The Art ◽  
Surface Current ◽  
Magnetic Surface ◽  
Magnetic Polarization ◽  
Research Directions ◽  
Magnetic Current ◽  
Asymmetric Reflection ◽  
Composite Layers ◽  
Electric And Magnetic Fields

AbstractMetasurfaces as optically thin composite layers can be modeled as electric and magnetic surface current sheets flowing in the layer volume in the metasurface plane. In the most general linear metasurface, the electric surface current can be induced by both incident electric and magnetic fields. Likewise, magnetic polarization and magnetic current can be induced also by external electric field. Metasurfaces which exhibit magnetoelectric coupling are called bianisotropic metasurfaces. In this review, we explain the role of bianisotropic properties in realizing various metasurface devices and overview the state-of-the-art of research in this field. Interestingly, engineered bianisotropic response is seen to be required for realization of many key field transformations, such as anomalous refraction, asymmetric reflection, polarization transformation, isolation, and more. Moreover, we summarize previously reported findings on uniform and gradient bianisotropic metasurfaces and envision novel and prospective research directions in this field.

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