Up to 300†K lasing with GeSn-On-Insulator microdisk resonators.

GeSn alloys are the most promising direct band gap semiconductors to demonstrate full CMOS-compatible laser integration with a manufacturing from Group-IV materials. Here, we show that room temperature lasing, up to 300 K, can be obtained with GeSn. This is achieved in microdisk resonators fabricated on a GeSn-On-Insulator platform by combining strain engineering with a thick layer of high Sn content GeSn.

Lasing in strained germanium microbridges.

Germanium has long been regarded as a promising laser material for silicon based opto-electronics. It is CMOS-compatible and has a favourable band structure, which can be tuned by strain or alloying with Sn to become direct, as it was found to be required for interband semiconductor lasers. Here, we report lasing in the mid-infrared region (from λ = 3.20 µm up to λ = 3.66 µm) in tensile strained Ge microbridges uniaxially loaded above 5.4% up to 5.9% upon optical pumping, with a differential quantum efficiency close to 100% with a lower bound of 50% and a maximal operating temperature of 100 K. We also demonstrate the effect of a non-equilibrium electron distribution in k-space which reveals the importance of directness for lasing. With these achievements the strained Ge approach is shown to compare well to GeSn, in particular in terms of efficiency.

Age-Related Parameters of the Spinal Inhibition of Skeletal Muscles in the Regulation of Voluntary Movements in Males.

We studied the age-related features of spinal inhibition in the regulation of voluntary movements in males. It was found that presynaptic, nonreciprocal and reciprocal inhibition of the flexor of toes during voluntary movements was less intense as compared with relative muscle rest in all studied age groups. This results from the age-related features of supraspinalactivatory and inhibitory effects on la and Ib spinal interneurons, which change the mechanism of spinal inhibition of voluntary movements during the development of the organism. In boys aged 9-12 years, the presynaptic inhibition of Iaafferents is lowest, while the nonreciprocal and reciprocal inhibition of (αmotoneurons of the flexor of toes is highest among all studied age groups. In boys aged 14-15 years, the presynaptic inhibition of Iαafferents is higher, while the nonreciprocal and reciprocal inhibition of cxmotoneurons of the flexor of toes is lowest among the age groups. By the age of 17-18 years, the mechanism of nonreciprocal inhibition of αmotoneurons of the flexor of toes during voluntary movements is similar to that at the age of 14-15 years. The final level of presynaptic inhibition of Iαafferents and reciprocal inhibition of αmotoneurons. is reached at the age of 17-18 years.

[Age Peculiarities of Formation of Spinal Inhibition of Skeletal Muscle in Males].

Age peculiarities of spinal inhibition in males in the relative muscular rest condition were studied. The main stages of development and formation processes of spinal inhibition in males, and set periods of weakening and increasing during ontogeny. It's shown, that the development and formation of different types of spinal inhibition in the period from 9 to 18 years there heterochronically and definitive level of their development are on a different age: presynaptic inhibition of heteronymous Ia afferent and reciprocal inhibition homonymous α-motoreurons in the age of 9-12 years, recurrent inhibition of heteronymous α-motorneurons--17-18 years, and nonreciprocal inhibition of heteronymous and homonymous α-motorneurons--14-15 years. Teenage age is a critical period in the development of presynaptic inhibition heteronymous and homonymous Ia afferents, recurrent inhibition α-motorneurons. Discusses the physiological mechanisms underlying the observed age-specific patterns.

Observation of near-field dipolar interactions involved in a metal nanoparticle chain waveguide.

We present near-field measurements of transverse plasmonic wave propagation in a chain of gold elliptical nanocylinders fed by a silicon refractive waveguide at optical telecommunication wavelengths. Eigenmode amplitude and phase imaging by apertureless scanning near-field optical microscopy allows us to measure the local out-of-plane electric field components and to reveal the exact nature of the excited localized surface plasmon resonances. Furthermore, the coupling mechanism between subsequent metal nanoparticles along the chain is experimentally analyzed by spatial Fourier transformation on the complex near-field cartography, giving a direct experimental proof of plasmonic Bloch mode propagation along array of localized surface plasmons. Our work demonstrates the possibility to characterize multielement plasmonic nanostructures coupled to a photonic waveguide with a spatial resolution of less than 30 nm. This experimental work constitutes a prerequisite for the development of integrated nanophotonic devices.

A generic approach for vertical integration of nanowires.

We report on the collective integration technology of vertically aligned nanowires (NWs). Si and ZnO NWs have been used in order to develop a generic technological process. Both mineral and organic planarizations of the as-grown nanowires have been achieved. Chemical vapour deposition (CVD) oxides, spin on glass (SOG), and polymer have been investigated as filling materials. Polishing and/or etching of the composite structures have been set up so as to obtain a suitable morphology for the top and bottom electrical contacts. Electrical and optical characterizations of the integrated NWs have been performed. Contacts ohmicity has been demonstrated and specific contact resistances have been reported. The photoconducting properties of polymer-integrated ZnO NWs have also been investigated in the UV-visible range through collective electrical contacts. A small increase of the resistivity in the ZnO NWs under sub-bandgap illumination has been observed and discussed. A comparison of the photoluminescence (PL) spectra at 300 K of the as-grown and SOG-integrated ZnO nanowires has shown no significant impact of the integration process on the crystal quality of the NWs.

Wide angularly isotropic photonic bandgaps obtained from two-dimensional photonic crystals with Archimedean-like tilings.

We present a theoretical study of new two-dimensional photonic crystals based on Archimedean-like tilings. Three structures are considered: a square lattice with a 4-atom unit cell and triangular lattices with 7- and 13-atom unit cells. A 12-fold local rotational symmetry is obtained for the triangular lattices and is approached for the square lattice. Wide photonic bandgaps can then be achieved, with very weak bandwidth dependence (~1%) on the wave-propagation direction. The complete bandgap frequency is shown to depend on the atomic bond length and not on the crystal period. This new class of periodic photonic crystals is a simple and attractive alternative to photonic quasi crystals.