Second harmonic generation and broad-band photoluminescence in mesoporous Si/SiO nanoparticles.

Efficient second harmonic generation and broad-band photoluminescence from deeply subwavelength and nontoxic nanoparticles is essential for nanophotonic applications. Here, we explore nonlinear optical response from mesoporous Si/SiO, SiO, and Si nanoparticles, considering various fabrication and treatment procedures. We show that thermal annealing (including femtosecond laser treatment) of mesoporous Si/SiO nanoparticles provides the transformation of Si phase from amorphous to crystalline, enhancing the second harmonic and nonlinear photoluminescent response.

Cells have the ability to break and chemically modify GaP(As) nanowires.

Semiconductor nanowires are known for their unusual geometry, providing unique electronic and optical properties. Substrates with vertical nanowires have highly non-uniform surfaces, which are attractive in terms of the study of live cells that can interact and be labeled with the wires. Despite several previous works studying cells cultivated over nanowires, questions regarding cell rupture and interaction with the wires remain open.

Registration of activity of a single molecule of horseradish peroxidase using a detector based on a solid-state nanopore.

This work demonstrates the use of a solid-state nanopore detector to monitor the activity of a single molecule of a model enzyme, horseradish peroxidase (HRP). This detector includes a measuring cell, which is divided into cis- and trans- chambers by a silicon nitride chip (SiN structure) with a nanopore of 5 nm in diameter. To entrap a single HRP molecule into the nanopore, an electrode had been placed into the cis-chamber; HRP solution was added into this chamber after application of a negative voltage.

UV-A Flexible LEDs Based on Core-Shell GaN/AlGaN Quantum Well Microwires.

Nanostructured ultraviolet (UV) light sources represent a growing research field in view of their potential applications in wearable optoelectronics or medical treatment devices. In this work, we report the demonstration of the first flexible UV-A light emitting diode (LED) based on AlGaN/GaN core-shell microwires. The device is based on a composite microwire/poly(dimethylsiloxane) (PDMS) membrane with flexible transparent electrodes.

Registration of Functioning of a Single Horseradish Peroxidase Macromolecule with a Solid-State Nanopore.

Currently, nanopore-based technology for the determination of the functional activity of single enzyme molecules continues its development. The use of natural nanopores for studying single enzyme molecules is known. At that, the approach utilizing artificial solid-state nanopores is also promising but still understudied.

All-optical generation of static electric field in a single metal-semiconductor nanoantenna.

Electric field is a powerful instrument in nanoscale engineering, providing wide functionalities for control in various optical and solid-state nanodevices. The development of a single optically resonant nanostructure operating with a charge-induced electrical field is challenging, but it could be extremely useful for novel nanophotonic horizons. Here, we show a resonant metal-semiconductor nanostructure with a static electric field created at the interface between its components by charge carriers generated via femtosecond laser irradiation.

Photoluminescence imaging of single photon emitters within nanoscale strain profiles in monolayer WSe.

Local deformation of atomically thin van der Waals materials provides a powerful approach to create site-controlled chip-compatible single-photon emitters (SPEs). However, the microscopic mechanisms underlying the formation of such strain-induced SPEs are still not fully clear, which hinders further efforts in their deterministic integration with nanophotonic structures for developing practical on-chip sources of quantum light. Here we investigate SPEs with single-photon purity up to 98% created in monolayer WSe via nanoindentation.

Femtosecond Laser-Printed Gold Nanoantennas for Electrically Driven and Bias-Tuned Nanoscale Light Sources Operating in Visible and Infrared Spectral Ranges.

Nanoscale electrically driven light-emitting sources with tunable wavelength represent a milestone for implementation of integrated optoelectronic chips. Plasmonic nanoantennas exhibiting an enhanced local density of optical states (LDOS) and strong Purcell effect hold promise for fabrication of bright nanoscale light emitters. Here, we justify gold parabola-shaped nanobumps and their ordered arrays produced by direct ablation-free femtosecond laser printing as broadband plasmonic light sources electrically excited by a probe of scanning tunneling microscope (STM).

Elastic Gallium Phosphide Nanowire Optical Waveguides-Versatile Subwavelength Platform for Integrated Photonics.

Emerging technologies for integrated optical circuits demand novel approaches and materials. This includes a search for nanoscale waveguides that should satisfy criteria of high optical density, small cross-section, technological feasibility and structural perfection. All these criteria are met with self-assembled gallium phosphide (GaP) epitaxial nanowires.

Laser-Activated Second Harmonic Generation in Flexible Membrane with Si Nanowires.

Nonlinear silicon photonics has a high compatibility with CMOS technology and therefore is particularly attractive for various purposes and applications. Second harmonic generation (SHG) in silicon nanowires (NWs) is widely studied for its high sensitivity to structural changes, low-cost fabrication, and efficient tunability of photonic properties. In this study, we report a fabrication and SHG study of Si nanowire/siloxane flexible membranes.

First steps in the development of next-generation chirped volume Bragg gratings by means of fs laser inscription in fused silica.

The first steps towards the development and characterization of next-generation chirped volume Bragg gratings (CVBGs) by means of fs laser inscription were made. Based on the phase mask inscription technique we realized CVBGs in fused silica with a 3 × 3 mm aperture and a length of almost 12 mm with a chirp rate of ∼190 ps/nm around a central wavelength of 1030.5 nm.

Upgrading the front end of the petawatt-class PEARL laser facility.

A new front-end laser system with optical synchronization of chirped femtosecond and pump pulses for the petawatt laser complex PEtawatt pARametric Laser (PEARL) has been developed. The new front-end system provides a broader femtosecond pulse spectrum, temporal shaping of the pump pulse, and a significant increase in the stability of the parametric amplification stages of the PEARL.

Extremely high frequency Schottky diodes based on single GaN nanowires.

Gallium nitride (GaN) is one of the most promising materials for high-frequency devices owing to its prominent material properties. We report on the fabrication and study of a series of Schottky diodes in the ground-signal-ground topology based on individual GaN nanowires. The electrical characterization of-curves demonstrated relatively high ideality factor value (about 6-9) in comparison to the planar Au/GaN diodes that can be attributed to the nanowire geometry.

Self-assembled photonic structure: a Ga optical antenna on GaP nanowires.

Semiconductor nanowires are the perfect platform for nanophotonic applications owing to their resonant, waveguiding optical properties and technological capabilities providing control over their crystalline and chemical compositions. The vapor-liquid-solid growth mechanism allows the formation of hybrid metal-dielectric nanostructures promoting sub-wavelength light manipulation. In this work, we explore both experimentally and numerically the plasmonic effects promoted by a gallium (Ga) nanoparticle optical antenna decorating the facet of gallium phosphide (GaP) nanowires.

Structural Features of Eu and Tb-Bipyridinedicarboxamide Complexes.

Photoluminescent lanthanide complexes of Eu and Tb as central atoms and ,-diisopropyl-[2,2'-bipyridine]-6,6'-dicarboxamide as ligand were synthesized. The structure of these complexes was established by single-crystal X-ray diffraction, mass spectrometry, H and C nuclear magnetic resonance, ultraviolet-visible, infrared spectroscopy, and thermogravimetry. Bipyridinic ligands provide formation of coordinatively saturated complexes of lanthanide ions and strong photoluminescence (PL).

Silicone Materials for Flexible Optoelectronic Devices.

Polysiloxanes and materials based on them (silicone materials) are of great interest in optoelectronics due to their high flexibility, good film-forming ability, and optical transparency. According to the literature, polysiloxanes are suggested to be very promising in the field of optoelectronics and could be employed in the composition of liquid crystal devices, computer memory drives organic light emitting diodes (OLED), and organic photovoltaic devices, including dye synthesized solar cells (DSSC). Polysiloxanes are also a promising material for novel optoectronic devices, such as LEDs based on arrays of III-V nanowires (NWs).

Nanoscale Electric Field Probing in a Single Nanowire with Raman Spectroscopy and Elastic Strain.

In this work we investigate the Raman response of extremely strained gallium phosphide nanowires. We analyze new strain-induced spectral phenomena such as 2-fold and 3-fold phonon peak splitting which arise due to nontrivial internal electric field distribution coupled with inhomogeneous strain. We show that high bending strain acts as a probe allowing us to define the electric field distribution with deep subwavelength resolution using the corresponding changes of the Raman spectra.

Supercritical fluid-assisted modification combined with the resynthesis of SmCoO as an effective tool to enhance the long-term performance of SmCoO-derived catalysts for the dry reforming of methane to syngas.

The dry reforming of methane to syngas (DRM) is of increasing significance concerning, first, the production of raw materials for commercial organic/petrochemical syntheses and for hydrogen energetic, and, second, the utilization of two most harmful greenhouse gases. Herein, new SmCoO-based DRM catalysts derived from heterometallic precursors and operated without preliminary reduction are reported. For the first time, the effect of supercritical fluids-assisted modification of the SmCoO-derived catalysts combined with the re-oxidation of spent catalysts to SmCoO onto its long-term performance was studied.

Ni/(RO,CaO) Nanocomposites Produced by the Exsolution of RCaNiO Nickelates (R = Nd, Sm, Eu): Rare Earth Effect on the Catalytic Performance in the Dry Reforming and Partial Oxidation of Methane.

In order to clarify the role of RO in the metal-oxide catalysts derived from complex oxide precursors, a series of RCaNiO (R = Nd, Sm, Eu) complex oxides was obtained. A significant systematic increase in the orthorhombic distortion of the RCaNiO structure (KNiF type, Cmce) from Nd to Eu correlates with a corresponding decrease in their ionic radii. A reduction of RCaNiO in the Ar/H gas mixture at 800 °C causes a formation of dense agglomerates of CaO and RO coated with spherical 25-30 nm particles of Ni metal.

Temporal compression of high-power IR laser pulses in a KDP crystal.

It is shown that a KDP crystal can be used for temporal compression of powerful pulses of the near-IR range. A method of searching for laser beam and crystal parameters suitable for compression is proposed. Temporal compression of laser pulses at a central wavelength of 1034 nm from 266 fs to 94 fs during propagation along the optical axis in a 21 cm thick KDP crystal is demonstrated experimentally.

Tuning the Optical Properties and Conductivity of Bundles in Networks of Single-Walled Carbon Nanotubes.

The films of single-walled carbon nanotubes (SWCNTs) are a promising material for flexible transparent electrodes, which performance depends not only on the properties of individual nanotubes but also, foremost, on bundling of individual nanotubes. This work investigates the impact of densification on optical and electronic properties of SWCNT bundles and fabricated films. Our ab initio analysis shows that the optimally densified bundles, consisting of a mixture of quasi-metallic and semiconducting SWCNTs, demonstrate quasi-metallic behavior and can be considered as an effective conducting medium.

[Medical rehabilitation in patients with anal incompetence after surgery for stage IV hemorrhoids].

Unlabelled: The choice of medical rehabilitation in patients with anal incontinence is impossible without diagnostic data revealing the mechanism of fecal incontinence. The most promising are programs of comprehensive physiotherapeutic rehabilitation based on biofeedback training. The rate of anal incompetence (AI) after hemorrhoidectomy is 1.

Light-Emitting Diodes Based on InGaN/GaN Nanowires on Microsphere-Lithography-Patterned Si Substrates.

The direct integration of epitaxial III-V and III-N heterostructures on Si substrates is a promising platform for the development of optoelectronic devices. Nanowires, due to their unique geometry, allow for the direct synthesis of semiconductor light-emitting diodes (LED) on crystalline lattice-mismatched Si wafers. Here, we present molecular beam epitaxy of regular arrays n-GaN/i-InGaN/p-GaN heterostructured nanowires and tripods on Si/SiO substrates prepatterned with the use of cost-effective and rapid microsphere optical lithography.

Femtosecond Laser-Assisted Formation of Hybrid Nanoparticles from Bi-Layer Gold-Silicon Films for Microscale White-Light Source.

It is very natural to use silicon as a primary material for microelectronics. However, silicon application in nanophotonics is limited due to the indirect gap of its energy band structure. To improve the silicon emission properties, it can be combined with a plasmonic part.