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View Article and Find Full Text PDFNanomaterials (Basel)
June 2022
Photonic hypercrystals (PHCs) are materials combining hyperbolic metamaterials (HMMs) with widely used photonic crystals. We found that finite-sized Type-I HMMs can support unique electromagnetic modes, which could be utilized in two-dimensional photonic crystals to achieve PHCs with twisted bands in the infrared region. Numerical investigation of the PHCs showed that the twisted bands have degenerate points that can support all-angle self-collimation effects.
View Article and Find Full Text PDFHigh-speed optical amplitude modulation is important for optical communication systems and sensors. Moreover, nano-optical modulators are important for developing optical-communication-aided high-speed parallel-operation processors and micro-biomedical sensors for inside-blood-capillary examinations or microsurgery operations. In this paper, we have designed a plasmonic resonant tunable metasurface with barium titanate (BTO) as a nanoscale optical modulator with a high modulation index and high speed.
View Article and Find Full Text PDFNovel approaches to synthesize efficient inorganic electride [CaAlO](e) (thereafter, C12A7:e) at ambient pressure under nitrogen atmosphere, are actively sought out to reduce the cost of massive formation of nanosized powder as well as compact large size target production. It led to a new era in low cost industrial applications of this abundant material as Transparent Conducting Oxides (TCOs) and as a catalyst. Therefore, the present study about C12A7:e electride is directed towards challenges of cation doping in C12A7:e to enhance the conductivity and form target to deposit thin film.
View Article and Find Full Text PDFIn the present study we synthesized conductive nanoscale [CaAlO](4e) (hereafter denoted as CA:e) material, and reduced graphene oxide (rGO) was produced, which was unexpected; graphene oxide was removed after melting the sample. The conductivity of CA:e composites synthesized at 1550 °C was 1.25 S cm, and the electron concentration was 5.
View Article and Find Full Text PDFOne of the greatest challenges in the enhancement of the electrical properties of conductive mayenite [CaAlO](4e) (hereinafter C12A7:e) is the design of a more suitable/simple synthesis strategy that can be employed to obtain the required properties such as excellent stable electrical conductivity, a high electron concentration, outstanding mobility, and an exceptionally large surface area. Therefore, to synthesize C12A7:e in the metallic state, we proposed a facile, direct synthesis strategy based on an optimized sol-gel combustion method under a nitrogen gas environment using the low-cost precursors Ca(NO)·4HO and Al(NO)·9HO. Using this developed strategy, we successfully synthesized moderately conductive nanoscale C12A7:e powder, but with unexpected carbon components (reduced graphene oxide (rGO) and/or graphene oxide (GO)).
View Article and Find Full Text PDFWe propose a scheme of metal/dielectric/metal waveguide for the enhanced forward stimulated Brillouin scattering (FSBS) in diamond that is mediated by gap surface plasmons. Numerical results based on finite-element method show that the maximum Brillouin gain in the small gap (~100 nm) can exceed 10 W m, which is three orders of magnitude higher than that in diamond-only waveguides. It is found that the radiation pressure that exists at the boundaries of metal and diamond plays a dominant role in contributing to the enhanced forward stimulated Brillouin gain, although electrostrictive forces interfere destructively.
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