Fano resonance Rabi splitting of surface plasmons.

Rabi splitting and Fano resonance are well-known physical phenomena in conventional quantum systems as atoms and quantum dots, arising from strong interaction between two quantum states. In recent years similar features have been observed in various nanophotonic and nanoplasmonic systems. Yet, realization of strong interaction between two or more Fano resonance states has not been accomplished either in quantum or in optical systems.

High-Quality-Factor Mid-Infrared Toroidal Excitation in Folded 3D Metamaterials.

With unusual electromagnetic radiation properties and great application potentials, optical toroidal moments have received increasing interest in recent years. 3D metamaterials composed of split ring resonators with specific orientations in micro-/nanoscale are a perfect choice for toroidal moment realization in optical frequency considering the excellent magnetic confinement and quality factor, which, unfortunately, are currently beyond the reach of existing micro-/nanofabrication techniques. Here, a 3D toroidal metamaterial operating in mid-infrared region constructed by metal patterns and dielectric frameworks is designed, by which high-quality-factor toroidal resonance is observed experimentally.

Multispectral plasmon-induced transparency in hyperfine terahertz meta-molecules.

We experimentally and theoretically demonstrated an approach to achieve multispectral plasmon-induced transparency (PIT) by utilizing meta-molecules that consist of hyperfine terahertz meta-atoms. The feature size of such hyperfine meta-atoms is 400 nm, which is one order smaller than that of normal terahertz metamaterials. The hyperfine meta-atoms with close eigenfrequencies and narrow resonant responses introduce different metastable energy levels, which makes the multispectral PIT possible.

Mass Production of Nanogap Electrodes toward Robust Resistive Random Access Memory.

Nanogap electrodes arrays are fabricated by combining atomic layer deposition, adhesive tape, and chemical etching. A unipolar nonvolatile resistive-switching behavior is identified in the nanogap electrodes, showing stable, robust performance and the multibit storage ability, demonstrating great potential in ultrahigh-density storage. The formation and dissolution of Si conductive filaments and migration of Au atoms is the mechanism behind the resistive switching.

Spatially oriented plasmonic 'nanograter' structures.

One of the key motivations in producing 3D structures has always been the realization of metamaterials with effective constituent properties that can be tuned in all propagation directions at various frequencies. Here, we report the investigation of spatially oriented "Nanograter" structures with orientation-dependent responses over a wide spectrum by focused-ion-beam based patterning and folding of thin film nanostructures. Au nano units of different shapes, standing along specifically designated orientations, were fabricated.

3D conductive coupling for efficient generation of prominent Fano resonances in metamaterials.

We demonstrate a 3D conductive coupling mechanism for the efficient generation of prominent and robust Fano resonances in 3D metamaterials (MMs) formed by integrating vertical U-shape split-ring resonators (SRRs) or vertical rectangular plates along a planar metallic hole array with extraordinary optical transmission (EOT). In such a configuration, intensified vertical E-field is induced along the metallic holes and naturally excites the electric resonances of the vertical structures, which form non-radiative "dark" modes. These 3D conductive "dark" modes strongly interfere with the "bright" resonance mode of the EOT structure, generating significant Fano resonances with both prominent destructive and constructive interferences.

Sub-Nanometer Controllable Fabrication of Freestanding Hetero-Structures Through Plasma-Matter Interaction During Ion Irradiation.

Freestanding three-dimensional nanostructures have attracted intense attention for their potential application in novel electronic, optical, magnetic, biological and mechanical devices. However, controlled fabrication of highly-ordered, well-shaped and freestanding core-shell hetero-structures in large scale cost-effectively is still a challenge. Here we present the constructing of freestanding hetero-structures by taking advantages of lateral re-deposition, a phenomenon that occurred during plasma-matter interaction and usually to be minimized/avoided in conventional device fabrication.

High-Q lithium niobate microdisk resonators on a chip for efficient electro-optic modulation.

Lithium niobate (LN) microdisk resonators on a LN-silica-LN chip were fabricated using only conventional semiconductor fabrication processes. The quality factor of the LN resonator with a 39.6-μm radius and a 0.

Direct laser writing of pyramidal plasmonic structures with apertures and asymmetric gratings towards efficient subwavelength light focusing.

Efficient confining of photons into subwavelength scale is of great importance in both fundamental researches and engineering applications, of which one major challenge lies in the lack of effective and reliable on-chip nanofabrication techniques. Here we demonstrate the efficient subwavelength light focusing with carefully engineered pyramidal structures fabricated by direct laser writing and surface metallization. The important effects of the geometry and symmetry are investigated.

Changes in physicochemical properties and in vitro digestibility of common buckwheat starch by heat-moisture treatment and annealing.

Heat-moisture treatment (HMT) and annealing (ANN) were applied in the test to investigate how they can affect the physicochemical properties and in vitro digestibility of common buckwheat starch (CBS). In the practice, these two modification methods did not change typical 'A'-type X-ray diffraction pattern of CBS. However, the gelatinization temperature, amylose content, and relative crystallinity increased and peak viscosity value and gelatinization enthalpy of CBS declined significantly.

Erosion Mechanism of MoS2-Based Films Exposed to Atomic Oxygen Environments.

The erosion mechanism of magnetron sputtered MoS2 films exposed to the atomic oxygen environment was studied and compared with the Ti-doped MoS2 and MoS2/Ti multilayer films. The compositional and structural changes were investigated as a function of incident fluence by Rutherford back scattering (RBS) and focused ion beam combining with scanning electron microscopy (FIB&SEM). The RBS results indicate that the sulfur atoms are eroded by the incident atomic oxygen atoms and the removed sulfur amount increases but the erosion rate decreases with increasing of incident fluence.

Single grain boundary break junction for suspended nanogap electrodes with gapwidth down to 1-2 nm by focused ion beam milling.

Single grain boundary junctions are used for the fabrication of suspended nanogap electrodes with a gapwidth down to 1-2 nm through the break of such junctions by focused ion beam (FIB) milling. With advantages of stability and no debris, such nanogap electrodes are suitable for single molecular electronic device construction.

Protection of centre spin coherence by dynamic nuclear spin polarization in diamond.

We experimentally investigate the protection of electron spin coherence of a nitrogen-vacancy (NV) centre in diamond by dynamic nuclear spin polarization (DNP). The electron spin decoherence of an NV centre is caused by the magnetic field fluctuation of the (13)C nuclear spin bath, which contributes large thermal fluctuation to the centre electron spin when it is in an equilibrium state at room temperature. To address this issue, we continuously transfer the angular momentum from electron spin to nuclear spins, and pump the nuclear spin bath to a polarized state under the Hartmann-Hahn condition.

Metal-organic frameworks reactivate deceased diatoms to be efficient CO(2) absorbents.

Diatomite combined with certain metal-organic frameworks (MOFs) is shown to be an effective CO2 absorbent, although diatomite alone is regarded as inert with respect to CO2 absorption. This finding opens the prospect of reactivating millions of tons of diatomite for CO2 absorption. It also shows for the first time that diatom frustules can act as CO2 buffers, an important link in a successive biological CO2 concentration mechanism chain that impacts on global warming.

Thermally induced shape modification of free-standing nanostructures for advanced functionalities.

Shape manipulation of nanowires is highly desirable in the construction of nanostructures, in producing free-standing interconnect bridges and as a building block of more complex functional structures. By introducing asymmetry in growth parameters, which may result in compositional or microstructural non-uniformity in the nanowires, thermal annealing can be used to induce shape modification of free-standing nanowires. We demonstrate that such manipulation is readily achieved using vertically grown Pt-Ga-C composite nanowires fabricated by focused-ion-beam induced chemical vapor deposition.

Fabrication of sub-20 nm width ferromagnetic nanocontact structures by shadow evaporation.

The movement of the magnetic domain wall could result in the changing of the contact resistance. Such a resistance change is named as the domain wall Magnetoresistance (DWMR), which can be used as a basic signal of nanodevices. For application, a large DWMR is necessary to improve the device performance.

A training effect on electrical properties in nanoscale BiFeO3.

We report our observation of the training effect on dc electrical properties in a nanochain of BiFeO3 as a result of large scale migration of defects under the combined influence of electric field and Joule heating. We show that an optimum number of cycles of electric field within the range zero to ~1.0 MV cm(-1) across a temperature range 80-300 K helps in reaching the stable state via a glass-transition-like process in the defect structure.

Felling of individual freestanding nanoobjects using focused-ion-beam milling for investigations of structural and transport properties.

We report that, to enable studies of their compositional, structural and electrical properties, freestanding individual nanoobjects can be selectively felled in a controllable way by the technique of low-current focused-ion-beam (FIB) milling with the ion beam at a chosen angle of incidence to the nanoobject. To demonstrate the suitability of the technique, we report results for zigzag/straight tungsten nanowires grown vertically on support substrates and then felled for characterization. We also describe a systematic investigation of the effect of the experimental geometry and parameters on the felling process and on the induced wire-bending phenomenon.

Large-scale ordered silicon microtube arrays fabricated by Poisson spot lithography.

A novel approach based on the Poisson spot effect in a conventional optical lithography system is presented for fabricating large-scale ordered ring patterns at low cost, in which the pattern geometries are tuned by controlling the exposure dose and deliberate design of the mask patterns. Following this by cryogenic deep etching, the ring patterns are transferred into Si substrates, resulting in various vertical tubular Si array structures. Microscopic analysis indicates that the as-fabricated Si microtubes have smooth interior and exterior surfaces that are uniform in size, shape and wall-thickness, which exhibit potential applications as electronic, biological and medical devices.

Coupled subwavelength gratings for surface-enhanced Raman spectroscopy.

Dual subwavelength Ag gratings with a small gap of about 15 nm are demonstrated to provide a huge additional SERS enhancement, more than 10(3) fold in scattering efficiency over normal SERS on an Ag film due to the strong plasmon coupling, which is simulated by theoretical calculation. The simulation also shows the advantages of the coupled two-layer gratings over the one-layer grating for SERS measurement. Our study provides a promising and feasible way of structure design for extremely sensitive substrates of SERS.

Superconductivity of freestanding tungsten nanofeatures grown by focused-ion-beam.

Freestanding tungsten composite nanofeatures were grown by focused-ion-beam-induced deposition with 1 pA ion beam current. The temperature dependent electrical measurements show that the flying nanoscale tungsten is conducting with a room temperature resistivity of 550 micro omega cm. It is also superconducting with a Tc, above 5.