Optical generation of intense ultrashort magnetic pulses at the nanoscale

Generating, controlling and sensing strong magnetic fields at ever shorter time and length scales is important for both fundamental solid-state physics and technological applications such as magnetic data recording. Here, we propose a scheme for producing strong ultrashort magnetic pulses localized at the nanoscale. We show that a bimetallic nanoring illuminated by femtosecond laser pulses responds with transient thermoelectric currents of picosecond duration, which in turn induce Tesla-scale magnetic fields in the ring cavity. Our method provides a practical way of generating intense nanoscale magnetic fields with great potential for materials characterization, terahertz radiation generation and data storage applications

Achieving accurate FTIR measurements on high performance bandpass filters

The sources of ordinate error in FTIR spectrometers are reviewed with reference to measuring small out-of-band features in the spectra of bandpass filters. Procedures for identifying instrumental artefacts are described. It is shown that features well below 0.01%T can be measured reliably

Electron beam excitation of plasmonic modes in gold dimers

We report on the first realization of hyperspectral imaging for visualization and excitation of plasmon modes in dimers of 100 nm gold decahedra by a scanning electron beam

Focal-plane arrays: nanohole arrays enable multiple-point-source imaging

A new type of focal-plane array made of a nanoscale metal screen mimics the function of a lens, focuses light (and plasmons) into subwavelength hot spots, and achieves high-resolution imaging of complex sources

Free-electron pumped tunable nanoscale light-source: the 'light-well'

We report on the first experimental demonstration of a new type of electron-beamdriven radiation source, a 'light-well', which can be used as a tunable nanoscale emitter of optical radiation and surface plasmon-polaritons (SPPs)

Understanding the epigenetic methylation and miRNA mediated gene regulation of transcellular calcium transport genes in avian uterus during egg calcification

Calcium contents of eggs in IWI and IW

Graphene plasmon waveguiding and hybridization in individual and paired nanoribbons

Plasmons in doped graphene exhibit relatively large confinement and long lifetime compared to noble-metal plasmons. Here, we study the propagation properties of plasmons guided along individual and interacting graphene nanoribbons. Besides their tunability via electrostatic gating, an additional handle to control these excitations is provided by the dielectric environment and the relative arrangement of the interacting waveguides. Plasmon interaction and hybridization in pairs of neighboring aligned ribbons are shown to be strong enough to produce dramatic modifications in the plasmon field profiles. We introduce a universal scaling law that considerably simplifies the analysis an understanding of these plasmons. Our work provides the building blocks to construct graphene plasmon circuits for future compact plasmon devices with potential application to optical signal processing, infrared sensing, and quantum information technology

Amplification of the evanescent field of free electrons

Evanescent optical fields existing in close proximity to illuminated objects contain detailed information on length scales smaller than the wavelength. They do not propagate to external observers but can be accessed using negative-index lenses, or coupled to propagating waves via subwavelength apertures, to achieve imaging resolution beyond the diffraction limit. Free electrons moving in vacuum also carry imperceptible localized, visible-frequency evanescent fields, and we demonstrate experimentally here that these fields can be amplified by a plasmonic film as electrons fly over the surface, offering new avenues toward the exploitation of electron evanescent fields for enhanced microscopy and nanoscale light generation. Amplifiers are fabricated at the tips of tapered optical fiber probes decorated with nanogratings to resonantly scatter electron fields to UV/vis light. We record amplification factors up to 3.4 in the ~850 THz (~350 nm) spectral range for medium-energy (40–50 keV) electrons

An optical fiber network oracle for NP-complete problems

The modern information society is enabled by photonic fiber networks of huge coverage and complexity, from transcontinental submarine telecommunication cables to fiber to the home local segments. This world-wide network has yet to match the complexity of human brain containing a hundred billion neurons, with thousands synaptic connections each in average, but already exceeds the complexity of brains of primitive organisms, such as honey bee containing about one million neurons. With this paper we bring about a discussion on the computing potential of optical networks as information carriers. Using a simple fiber network we provide a proof-of-principle demonstration that it can be seen as an optical oracle for the Hamiltonian path problem, the famous mathematical complexity problem of finding if a map can be travelled so that each town is visited once only. Pronouncement of a Hamiltonian path is made by monitoring the delay of the optical pulse interrogating the network, which shall be equal to the sum of travel times visiting all the nodes (towns). We argue that the optical oracle could solve this NP-complete problem hundreds times faster than brute-force computing, discuss its secure communication applications, and propose possible implementation in silicon photonics and plasmonic networks