Rabi-like splitting and refractive index sensing with hybrid Tamm plasmon-cavity modes

Rabi-like splitting and self-referenced refractive index sensing in hybrid plasmonic-1D photonic crystal structures have been theoretically demonstrated. The coupling between Tamm plasmon and cavity photon modes are tuned by incorporating a low refractive index spacer layer adjacent to the metallic layer to form their hybrid modes. Anticrossing of the modes observed at different values of spacer layer thickness validates the strong coupling between the two modes and causes Rabi-like splitting with different splitting energy. The modes coupling has been supported by coupled mode theory. Rabi-like splitting energy decreases with increasing number of periods (N) and refractive index contrast (η) of two dielectric materials used to make the 1D photonic crystals, and the observed variation is explained by an analytical model. Angular and polarization dependency of the hybrid modes shows that the polarization splitting of the lower hybrid mode is much stronger than that of the upper hybrid mode. On further investigation, it is seen that one of the hybrid modes remains unchanged while other mode undergoes significant change with varying the cavity medium. This nature of the hybrid modes has been utilized for designing self-referenced refractive index sensors for sensing different analytes. For η=1.333 and N=10 in a hybrid structure, the sensitivity increases from 51 nm/RIU to 201 nm/RIU with increasing cavity thickness from 170 nm to 892 nm. For the fixed cavity thickness of 892 nm, the sensitivity increases from 201 nm/RIU to 259 nm/RIU by increasing η from 1.333 to 1.605. The sensing parameters such as detection accuracy, quality factor, and figure of merit for two different hybrid structures ([η=1.333, N=10] and [η=1.605, N=6]) have been evaluated and compared. The value of resonant reflectivity of one of the hybrid modes changes considerably with varying analyte medium which can be used for refractive index sensing.

Contact-electro-catalysis for the degradation of organic pollutants using pristine dielectric powders

Mechanochemistry has been studied for some time, but research on the reactivity of charges exchanged by contact-electrification (CE) during mechanical stimulation remains scarce. Here, we demonstrate that electrons transferred during the CE between pristine dielectric powders and water can be utilized to directly catalyze reactions without the use of conventional catalysts. Specifically, frequent CE at Fluorinated Ethylene Propylene (FEP) - water interface induces electron-exchanges, thus forming reactive oxygen species for the degradation of an aqueous methyl orange solution. Contact-electro-catalysis, by conjunction of CE, mechanochemistry and catalysis, has been proposed as a general mechanism, which has been demonstrated to be effective for various dielectric materials, such as Teflon, Nylon-6,6 and rubber. This original catalytic principle not only expands the range of catalytic materials, but also enables us to envisage catalytic processes through mechano-induced contact-electrification.

Broadband reflectors with a disordered layered structure: statistical properties of high performing configurations selected via genetic algorithm

Disordered multilayers consisting of alternating layers of two lossless dielectric materials with random thicknesses can behave as good reflectors in wide wavelength ranges except for narrow bands where the transmittance is significative. We use a dedicated genetic algorithm to select different configurations (thickness sequences) of such structures which exhibit very low transmittance in the entire visible wavelength range, showing that broadband disordered reflectors with very high performance can be designed. A statistical analysis of the thickness sequences selected by the genetic algorithm reveals that such sequences are characterized by correlated disorder and that the degree of autocorrelation is a key parameter in determining the reflection performance.

Adjusting the energy gap and interface effect of titania nanosheets synergistically enhances the energy storage performance of PVDF based composites

Polymeric dielectric materials have recently attracted much attention due to their very high potential for use as advanced energy storage capacitors. However, it is still challenging to improve the inherent...

OuroborosBEM: a fast multi-GPU microscopic Monte Carlo simulation for gaseous detectors and charged particle dynamics

The design of gaseous detectors for accelerator, particle and nuclear physics requires simulations relying on multi-physics aspects. In fact, these simulations deal with the dynamics of a large number of charged particles interacting in a gaseous medium immersed in the electric field generated by a more or less complex assembly of electrodes and dielectric materials. We report here on a homemade software, called ouroborosbem, able to tackle the different features involved in such simulations. After solving the electrostatic problem for which a solver based on the boundary element method (BEM) has been implemented, particles are tracked and will microscopically interact with the gas medium. Dynamical effects have been included such as the electron-ion recombination process, the charging-up of the dielectric materials and other space charge effects that might alter the detector performances. These were made possible thanks to the nVidia CUDA language specifically optimised to run on Graphical Processor Units (GPUs) to minimize the computing times. Comparisons of the results obtained for parallel plate avalanche counters and GEM detectors to literature data on swarm parameters fully validate the performances of ouroborosbem. Moreover, we were able to precisely reproduce the measured gains of single and double GEM detectors as a function of the applied voltage.

Ultra-low temperature co-fired ceramics with adjustable microwave dielectric properties in Na2O-Bi2O3-MoO3 ternary system: A comprehensive study

Herein, a series of microwave dielectric materials in the Na2O-Bi2O3-MoO3 ternary system were studied via phase identification, microstructure characterization, spectral analysis and microwave dielectric properties test, such as Na2MoO4, Na6Mo10O33,...

Ultrahigh Permittivity, Ultralow Loss and Stability in (In0.5Ta0.5)0.1Ti0.9O2 Ceramics With Temperature Range From -100 to 235 °C

Dielectric materials with excellent dielectric properties are being promoted in requirements of microelectronic devices. In this study, (In0.5Ta0.5)0.1Ti0.9O2 ceramics were achieved by a solid-state reaction with reducing atmosphere of N2. Also, dense microstructure, ultrahigh permittivity (εr = 1.18 × 105) and ultralow dielectric loss (tanδ = 0.0072) were demonstrated at1 kHz. Interestingly enough, the temperature coefficient of permittivity which satisfies X9D (-100 °C - 235 °C, Δεr/ε25°C < ± 3.3 %) maintained stability at 1 kHz, and the dielectric mechanism could be connected to the electron-pinned defect dipoles (EPDD), which has favourable potential applications in electronic devices.

Inorganic dielectric materials for energy storage applications: a review

The intricacies in identifying the appropriate material system for energy storage applications have been the biggest struggle of the scientific community. Countless contributions by researchers worldwide have now helped us identify the possible snags and limitations associated with each material/method. This review intends to briefly discuss state of the art in energy storage applications of dielectric materials such as linear dielectrics, ferroelectrics, anti-ferroelectrics, and relaxor ferroelectrics. Based on the recent studies, we find that the eco-friendly lead-free dielectrics, which have been marked as inadequate to compete with lead-based systems, are excellent for energy applications. Moreover, some promising strategies to improve the functional properties of dielectric materials are discussed.

Installation for studying the parameters of localiInstallation for studying the parameters of localization of an electromagnetic wave in a waveguide of variable cross-section in the framework of the predictions of the 5-D extended space modelzation of an electromagnetic wave in a waveguide of variable cross-section in the framework of the predictions of the 5-D extended space model

The paper describes the creation and testing of an experimental setup for studying the parameters of localization of electromagnetic microwave radiation with a power of 0.001-0.004 W in the range of 36.0-79.0 GHz when propagating radiation in metal waveguides of variable cross-section. Measurements will also be carried out under conditions of filling the waveguide with dielectric materials with refractive indices from 1.46 to 4.0 for microwave radiation of the specified range. The installation is designed to measure the parameters of the localization of microwave radiation when it passes through a waveguide of variable cross-section, filled with materials with different refractive indices. Interpretation of the results will be carried out within the framework of the 5-D extended space model (ESM). The extended space model is formulated in (1+4)-dimensional space time-coordinate-interval. An additional spatial coordinate in the ESM is the interval. In the conjugate 5-D space, the energy-momentum-mass interval in the ESM corresponds to mass. In the ESM formalism, the question of the appearance of a nonzero variable mass in a photon and its localization under the influence of an external field is studied.