University of Sannio

About: University of Sannio is a education organization based out in Benevento, Italy. It is known for research contribution in the topics: Gravitational wave & LIGO. The organization has 1278 authors who have published 6125 publications receiving 167577 citations. The organization is also known as: Università degli Studi del Sannio & Universita degli Studi del Sannio.

New Neutral and Cationic Dialkylaluminium Complexes Bearing Imino‐Amide or Imino‐Phenoxide Ligands: Synthesis, Characterization and Reactivity With Olefins

Abstract: The synthesis and the characterization of some new aluminium complexes carrying bidentate monoanionic imino-amide or imino-phenoxide ligands are described. Reaction of 1-(o,o′-diisopropylphenylamino)-6-(o,o′-diisopropylphenylimino)cyclohexene with AlMe3 proceeded by methane elimination to produce the yellow compound dimethylaluminium N-(o,o′-diisopropylphenyl)-6-[N-(o,o′-diisopropylphenyl)imido]-1-cyclohexen-1-amide (1). In contrast, reaction of the same ligand with AlEt3 under the same experimental conditions involved the 1,4-addition of AlEt3 to the α,β-unsaturated imine, and led to the highly crystalline diethylaluminium N(o,o′-diisopropylphenyl)-2-[(o,o′-diisopropylphenyl)amino]3-ethyl-1-cyclohexen-1-amide (2). The structures of compounds 1 and 2 were determined by single-crystal X-ray diffraction. Thermolysis of 2 gave rise to ethane elimination, and led to the oily bis(amido) monoethyl derivative. Treatment of the salicylaldimine ligands 3-tBu-2-(OH)C6H3CH=N−R with AlMe3 yielded the dimethylaluminium compounds {3-tBu-2-(O)C6H3CH=N−R}AlMe2 [R = C6H5 (3); 2,6-iPr2C6H3 (4); and C6F5 (5)]. Compounds 1, 3, and 5 underwent methyl abstraction reactions with B(C6F5)3; trapping of the cationic species was accomplished in the presence of THF in dichloromethane solution. Preliminary polymerization tests were carried out for the synthesized Al complexes. Toluene solutions of 3, 4, and 5, when activated with 1 equiv. of B(C6F5)3, polymerised ethylene (1 atm) to solid polyethylene with low activity.

Optical fiber tip templating using direct focused ion beam milling

Abstract: We report on a method for integrating sub-wavelength resonant structures on top of optical fiber tip. Our fabrication technique is based on direct milling of the glass on the fiber facet by means of focused ion beam. The patterned fiber tip acts as a structured template for successive depositions of any responsive or functional overlay. The proposed method is validated by depositing on the patterned fiber a high refractive index material layer, to obtain a 'double-layer' photonic crystal slab supporting guided resonances, appearing as peaks in the reflection spectrum. Morphological and optical characterizations are performed to investigate the effects of the fabrication process. Our results show how undesired effects, intrinsic to the fabrication procedure should be taken into account in order to guarantee a successful development of the device. Moreover, to demonstrate the flexibility of our approach and the possibility to engineering the resonances, a thin layer of gold is also deposited on the fiber tip, giving rise to a hybrid photonic-plasmonic structure with a complementary spectral response and different optical field distribution at the resonant wavelengths. Overall, this work represents a significant step forward the consolidation of Lab-on-Fiber Technology.

Optical guided mode resonance filter on a flexible substrate

Abstract: We demonstrate the operation of a flexible optical filter based on guided mode resonances that operates in the visible regime. The filter is fabricated on a free standing polymeric membrane of 1.3 μm thickness and we show how the geometrical design parameters of the filter determine its optical properties, and how various types of filter can be made with this scheme. To highlight the versatility and robustness of the approach, we mount a filter onto a collimated fibre output and demonstrate successful wavelength filtering.