We present experimental results on photonic crystal/photonic wire micro-cavity structures that demonstrate further enhancement of the quality-factor (Q-factor)--up to approximately 149,000--in the fibre telecommunications wavelength range. The Q-values and the useful transmission levels achieved are due, in particular, to the combination of both tapering within and outside the micro-cavity, with carefully designed hole diameters and non-periodic hole placement within the tapered section. Our 2D Finite Difference Time Domain (FDTD) simulation approach shows good agreement with the experimental results.

Asymmetric Split Ring Resonators are known to exhibit resonant modes where the optical electric field is strongest near the ends of the arms, thereby increasing the sensitivity of spectral techniques such as surface enhanced Raman scattering (SERS). By producing asymmetry in the structures, the two arms of the ring produce distinct plasmonic resonances related to their lengths - but are also affected by the presence of the other arm. This combination leads to a steepening of the slope of the reflection spectrum between the resonances that increases the sensitivity of the resonant behavior to the addition of different molecular species. We describe experimental results, supported by simulation, on the resonances of a series of circular split ring resonators with different gap and section lengths--at wavelengths in the mid-infra red regions of the spectrum--and their utilization for highly sensitive detection of organic compounds. We have used thin films of PMMA with different thicknesses, resulting in characteristic shifts from the original resonance. We also demonstrate matching of asymmetric split ring resonators to a molecular resonance of PMMA.

Metamaterial features in a dielectric fiber with an inserted thin cylindrical shell Appl. Phys. Lett. 101, 143508 (2012) Surface label-free sensing by means of a fluorescent multilayered photonic structure Appl. Phys. Lett. 101, 131105 (2012) Broadband super-Planckian thermal emission from hyperbolic metamaterials Appl. Phys. Lett. 101, 131106 (2012) High-Q AlN photonic crystal nanobeam cavities fabricated by layer transfer

Rhenium(v) in combination with tertiary phosphines as ligands has a strong tendency to form multiple bonds to nitrogen. Three new series of complexes containing such bonds, of the types [ReX,(NAr) (PRJJ, [ReNX,(PR,),], and [ReNX,(PR,),] (X = halogen, Ar = aryl, R = alkyl or aryl), are described. Imido-complexes are obtained by the reaction of the arylamine on the complexes [ReOX,(PR,),] or [ReOX,(OEt) (PR,),], and the nitrido complexes by hydrazine dihydrochloride reduction of potassium per-rhenate in the presence of the phosphine. The dipole moments, configurations, and structures of the new compounds are discussed, RHENIUM(V) HALIDES in combination with tertiary phosphines have a strong tendency to form stable multiple bonds to atoms, such as oxygen and nitrogen, in the groupings Re=O and Re=NPh.l Dipole moments show the Re=O and Re=NPh bonds to have considerable triple-bond character and may be represented Re + 0 and Re NPh, the arrows representing the drift of &electrons from the ligand into d-orbitals of the metal. The high bond order of the Re=O bond is also demonstrated by its length of 1-60 A, as compared with 1.87 A in [ReO2(CN),I2-.

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Three-dimensional (3D) photonic crystals (PhCs) are now beginning to acquire functionality via the use of dopants and heterostructures. However, the self-organized fabrication of large-area single crystals that are free of cracks and stacking faults has remained a challenge. We demonstrate a technology for the fabrication of (100)-oriented thin film 3D opal PhCs that exhibit no cracks over areas having no intrinsic size limit via a modified template-assisted colloidal self-assembly approach onto a patterned substrate. This technology potentially makes available large area regions of single photonic crystal, which can be used for optoelectronic devices.

Rheniurn-(III), -( IV) , and -(v) .

In this paper, we report on a substantial shift in the response of arrays of similarly sized Split Ring Resonators (SRRs), having a rectangular U-shaped form--and made respectively of aluminium and of gold. We also demonstrate that it is possible to obtain the polarization dependent LC peak in the visible spectrum--by using SRRs based on aluminium, rather than gold. The response of metallic SRRs scales linearly with size. At optical frequencies, metals stop behaving like nearly perfect conductors and begin displaying characteristically different behaviour, in accord with the Drude model. The response at higher frequencies, such as those in the visible and near infra-red, depends both on their size and on the individual properties of the metals used. A higher frequency limit has been observed in the polarization dependent response (in particular the LC resonance peak) of gold based SRRs in the near infrared region. By using aluminium based SRRs instead of gold, the higher frequency limit of the LC resonance can be further shifted into the visible spectrum.