Fluorescence anisotropy using highly polarized emitting dyes confined inside BNNTs.

Polarized fluorescence emission of nanoscale emitters has been extensively studied for applications such as bioimaging, displays, and optical communication. Extending the polarization properties in large assemblies of compact emitters is, however, challenging because of self-aggregation processes, which can induce depolarization effects, quenching, and cancellations of molecular dipoles. Here we use α-sexithiophene (6T) molecules confined inside boron nitride nanotubes (6T@BNNTs) to induce fluorescence anisotropy in a transparent host.

Comment on the paper "Improving Poor Man's Kramers-Kronig analysis and Kramers-Kronig constrained variational analysis".

The title paper [Spectrochim. Acta A213 (2019): 391-396] reports an improvement of the "Poor Man's Kramers-Kronig analysis" and of the "Kramers-Kronig constrained variational analysis" thanks to an ad hoc modification of some analytical formulas existing in the literature. This ad hoc modification is not based on mathematical grounds.

Hydroxide Ions Stabilize Open Carbon Nanotubes in Degassed Water.

The main hurdle preventing the widespread use of single-walled carbon nanotubes remains the lack of methods with which to produce formulations of pristine, unshortened, unfunctionalized, individualized single-walled carbon nanotubes, thus preserving their extraordinary properties. In particular, sonication leads to shortening, which is detrimental to percolation properties (electrical, thermal, mechanical, etc.).

Polymer-Decorated Carbon Nanotubes as Transducers for Label-Free Photonic Biosensors.

A biosensor taking advantage of the optical properties of sorted carbon nanotubes has been developed. A polyfluorene polymer bearing azido groups was synthesized and used for the selective extraction of semi-conducting nanotubes from the bulk population. The resulting polymer-decorated nanotubes were then conjugated by click-chemistry to a ligand unit (biotin), and the sensing properties of the biotinylated nanotubes were investigated by photoluminescence measurements, upon interaction with the streptavidin target.

Enhanced light emission from carbon nanotubes integrated in silicon micro-resonator.

Single-walled carbon nanotubes are considered a fascinating nanomaterial for photonic applications and are especially promising for efficient light emitters in the telecommunication wavelength range. Furthermore, their hybrid integration with silicon photonic structures makes them an ideal platform to explore their intrinsic properties. Here we report on the strong photoluminescence enhancement from carbon nanotubes integrated in silicon ring resonator circuits under two pumping configurations: surface-illuminated pumping at 735 nm and collinear pumping at 1.

Wavelength dependence of Pockels effect in strained silicon waveguides.

We investigate the influence of the wavelength, within the 1.3μm-1.63μm range, on the second-order optical nonlinearity in silicon waveguides strained by a silicon nitride (Si₃N ₄) overlayer.

Controlling carbon nanotube photoluminescence using silicon microring resonators.

We report on coupling between semiconducting single-wall carbon nanotubes (s-SWNT) photoluminescence and silicon microring resonators. Polyfluorene extracted s-SWNT deposited on such resonators exhibit sharp emission peaks, due to interaction with the cavity modes of the microring resonators. Ring resonators with radius of 5 μm and 10 μm were used, reaching quality factors up to 4000 in emission.

Light emission in silicon from carbon nanotubes.

The use of optics in microelectronic circuits to overcome the limitation of metallic interconnects is more and more considered as a viable solution. Among future silicon compatible materials, carbon nanotubes are promising candidates thanks to their ability to emit, modulate, and detect light in the wavelength range of silicon transparency. We report the first integration of carbon nanotubes with silicon waveguides, successfully coupling their emission and absorption properties.

Optical microcavity with semiconducting single-wall carbon nanotubes.

We report studies of optical Fabry-Perot microcavities based on semiconducting single-wall carbon nanotubes with a quality factor of 160. We experimentally demonstrate a huge photoluminescence signal enhancement by a factor of 30 in comparison with the identical film and by a factor of 180 if compared with a thin film containing non-purified (8,7) nanotubes. Furthermore, the spectral full-width at half-maximum of the photo-induced emission is reduced down to 8 nm with very good directivity at a wavelength of about 1.

Enhancement of semiconducting single-wall carbon-nanotube photoluminescence.

Photoluminescence properties of semiconducting single-wall carbon-nanotube (s-SWNT) thin films with different metallic single-wall carbon-nanotube (m-SWNT) concentrations are reported. s-SWNT purified samples are obtained by polymer-assisted selective extraction. We show that the presence of a few m-SWNTs in the sample generates a drastic quenching of the emission.

Raman scattering in crystalline oligothiophenes: a comparison between density functional theory and bond polarizability model.

Raman intensity of intramolecular and lattice modes of crystalline alpha-bithiophene (alpha-2T) are investigated within density functional theory using a nonlinear response formalism. First, comparison between the calculated Raman spectrum and the experimental data allows the assignment of the main Raman lines over the whole frequency range. Then, a bond polarizability (BP) model, limited to first neighbors, is built.

Separation of semiconducting from metallic carbon nanotubes by selective functionalization with azomethine ylides.

A mild and efficient method for the functionalization of SWNTs by cycloaddition of azomethine ylides derived from trialkylamine-N-oxides is described. Selective reaction of semiconducting carbon nanotubes was achieved by preorganizing the starting N-oxides on the nanotube surface prior to generating the reactive ylides. Separation of met-SWNTs from functionalized sem-SWNTs was successfully accomplished by inducing solubilization of sem-SWNTs in the presence of lignoceric acid.

Influence of structure on the optical limiting properties of nanotubes.

We investigate the role of carbon nanotubes structure on their optical limiting properties. Samples of different and well-characterized structural features are studied by optical limiting and pump-probe experiments. The influence of the diameter's size on the nano-object is demonstrated.

Ribotyping of coagulase-negative staphylococci with special emphasis on intraspecific typing of Staphylococcus epidermidis.

Coagulase-negative staphylococci (CoNS), particularly Staphylococcus epidermidis, are increasingly being recognized as opportunistic pathogens. They are often multiply antibiotic resistant and can cause nosocomial outbreaks. For clinical and epidemiological reasons, accurate species identification and typing are imperative.