There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Photonic crystal fibers guide light by corralling it within a periodic array of microscopic air holes that run along the entire fiber length Largely through their ability to overcome the limitations of conventional fiber optics—for example, by permitting low-loss guidance of light in a hollow core—these fibers are proving to have a multitude of important technological and scientific applications spanning many disciplines The result has been a renaissance of interest in optical fibers and their uses

https://science.sciencemag.org/content/sci/299/5605/358.full.pdf

Photonic crystal fibers

Since its discovery, the asymmetric Fano resonance has been a characteristic feature of interacting quantum systems. The shape of this resonance is distinctively different from that of conventional symmetric resonance curves. Recently, the Fano resonance has been found in plasmonic nanoparticles, photonic crystals, and electromagnetic metamaterials. The steep dispersion of the Fano resonance profile promises applications in sensors, lasing, switching, and nonlinear and slow-light devices.

The Fano resonance in plasmonic nanostructures and metamaterials

The organization of behavior: A neuropsychological theory

Today's telecommunications networks are still largely optically opaque - consisting of electronic nodes connected by point-to-point optical links, relying on a series of optical-electrical conversions. Moving to all-optical switching will allow increased bit rates and low latency movement of data, providing greater routing agility, reducing energy requirements and simplifying network structures. This promise, and indeed the fact that the fundamental capacity limits of existing infrastructure are being reached, has sparked renewed interest in the extension of telecommunications bands to longer infrared wavelengths (where lower intrinsic losses in fibre media are possible) and intense efforts to develop techniques based on space-division multiplexing (in which many distinguishable data paths are established through the same fibre strand using either multiple cores or a multimode core) to substantially increase capacity. Future network architectures will require a new generation of highly integrated devices capable of functions such as all-optical switching and mode (de)multiplexing. We report here on the proof-of-principle demonstration of a non-volatile all-optical switch that combines the chalcogenide glass phase-change medium widely used in rewritable optical disks with nanostructured plasmonic metamaterials to yield a high-contrast, large area, reversible switching solution that may be optimised to function across a broad infrared band.

An All‐Optical, Non‐volatile, Bidirectional, Phase‐Change Meta‐Switch

Differential scanning calorimetry (DSC) is widely used to study the stability of amorphous solids, characterizing the kinetics of crystallization close to the glass-transition temperature Tg. We apply ultrafast DSC to the phase-change material Ge2Sb2Te5 (GST) and show that if the range of heating rates is extended to more than 104 K s-1, the analysis can cover a wider temperature range, up to the point where the crystal growth rate approaches its maximum. The growth rates that can be characterized are some four orders of magnitude higher than in conventional DSC, reaching values relevant for the application of GST as a data-storage medium. The kinetic coefficient for crystal growth has a strongly non-Arrhenius temperature dependence, revealing that supercooled liquid GST has a high fragility. Near Tg there is evidence for decoupling of the crystal-growth kinetics from viscous flow, matching the behaviour for a fragile liquid suggested by studies on oxide and organic systems.

Characterization of supercooled liquid Ge2Sb2Te5 and its crystallization by ultrafast-heating calorimetry

We demonstrate an innovative concept for nanoscale electro-optic switching. It exploits the frequency shift of a narrow-band Fano resonance mode in a plasmonic planar metamaterial induced by a change in the dielectric properties of an adjacent chalcogenide glass layer. An electrically stimulated transition between amorphous and crystalline forms of the glass brings about a 150 nm shift in the near-infrared resonance providing transmission modulation with a contrast ratio of 4:1 in a device of subwavelength thickness.

/pdf/metamaterial-electro-optic-switch-of-nanoscale-thickness-1wgufrv2wp.pdf

Metamaterial electro-optic switch of nanoscale thickness

The fabrication of the first non-silica holey or microstructured optical fibre is reported. The chalcogenide glass gallium lanthanum sulphide was used. Applications of such fibres include optical switching, high power-delivery, acousto-optic devices, air-guiding fibres, fibre sensors, mid-IR devices, amongst others. In addition, holey fibre technology provides an improved route towards fabricating singlemode compound glass fibres

/pdf/chalcogenide-holey-fibres-1tdu5t1t6k.pdf

Chalcogenide holey fibres

NanoBioScience Lab, Istituto Italiano di Tecnologia, Via Morego 30, I16163 Genova, Italy andBIONEM Lab, University of Magna Graecia, viale Europa, I88100 Catanzaro, Italy(Dated: December 21, 2009)Combining metamaterials with functional media brings a new dimension to their performance.Here we demonstrate substantial resonance frequency tuning in a photonic metamaterial hybridizedwith an electrically/optically switchable chalcogenide glass. The transition between amorphousand crystalline forms brings about a 10% shift in the near-infrared resonance wavelength of anasymmetric split-ring array, providing transmission modulation functionality with a contrast ratioof 4:1 in a device of sub-wavelength thickness.

/pdf/phase-change-chalcogenide-glass-metamaterial-5dcsdhasfq.pdf

Daniel W. Hewak

Papers

An All‐Optical, Non‐volatile, Bidirectional, Phase‐Change Meta‐Switch

Characterization of supercooled liquid Ge2Sb2Te5 and its crystallization by ultrafast-heating calorimetry

Metamaterial electro-optic switch of nanoscale thickness

Chalcogenide holey fibres

Phase-change chalcogenide glass metamaterial