Search results for "germani"
showing 10 items of 488 documents
Broadband telecom to mid-infrared supercontinuum generation in a dispersion-engineered silicon germanium waveguide.
2015
We demonstrate broadband supercontinuum generation (SCG) in a dispersion-engineered silicon-germanium waveguide. The 3 cm long waveguide is pumped by femtosecond pulses at 2.4 μm, and the generated supercontinuum extends from 1.45 to 2.79 μm (at the −30 dB point). The broadening is mainly driven by the generation of a dispersive wave in the 1.5–1.8 μm region and soliton fission. The SCG was modeled numerically, and excellent agreement with the experimental results was obtained.
B-MINE, the balloon-borne microcalorimeter nuclear line explorer
2001
B-MINE is a concept for a balloon mission designed to probe the deepest regions of a supernova explosion by detecting Ti-44 emission at 68 keV with spatial and spectral resolutions that are sufficient to determine the extent and velocity distribution of the Ti-44 emitting region. The payload introduces the concept of focusing optics and microcalorimeter spectroscopy to nuclear line emission astrophysics. B-MINE has a thin, plastic foil telescope multilayered to maximize the reflectivity in a 20 keV band centered at 68 keV and a microcalorimeter array optimized for the same energy band. This combination provides a reduced background, an energy resolution of 50 eV and a 3sigma sensitivity in …
Electroplated Indium Bumps as Thermal and Electrical Connections of NTD-Ge Sensors for the Fabrication of Microcalorimeter Arrays
2012
We are developing a method to build arrays of Ge-based microcalorimeters for soft X-rays detection using micro-photolithographic techniques. A key element of the process is the electrical and thermal connection between the germanium sensors and the interconnection electrical tracks, that lay on a substrate acting as mechanical support and thermal sink. The geometry of the sensors, that have a square base truncated pyramid shape, makes feasible a connection through indium soldering. We describe a technique, based on microlithography and electroplating, adopted to grow indium bumps of a few tens of square microns of area and several microns high on top of the contact pads patterned on the sub…
Nonlinear femtosecond pulse propagation in all-solid photonic bandgap fiber
2009
Nonlinear femtosecond pulse propagation in all-solid photonic bandgap fiber is investigated experimentally and numerically for both the photonic bandgap guiding in the central silica core and the total internal reflection in germanium doped inclusions.
Stimulated Brillouin scattering in Germanium-doped-core optical fibers up to 98% mol doping level
2018
International audience; We experimentally investigate stimulated Brillouin scattering in several highly GeO2-doped optical fibers and report wide frequency tunability over more than 3 GHz and Brillouin gain 7 times larger than in standard silica fibers.
Data Transmissions at 1.98 µm in cm-long SiGe Waveguides
2017
International audience; We demonstrate an error-free transmission of 10-Gbit/s optical signals along a SiGe waveguide at a wavelength of 1.98 μm. Bit error rate measurements confirm the absence of penalty during the transmission through a 2.5-cm long waveguide having a width of 2.2 μm.
γ-ray induced GeODC(II) centers in germanium doped α-quartz crystal
2011
International audience; Main luminescence of α-quartz crystal doped with germanium results from the luminescence of a self-trapped exciton (STE) near germanium. In as grown Ge-doped α-quartz crystal, the luminescence associated with the twofold coordinated Ge center (GeODC) in amorphous silica glass doped with germanium, was never observed. In this work, we performed experiments to investigate if a GeODC like luminescence could appear after a γ-irradiation of a Ge-doped α-quartz crystal. The answer is positive: under excitation with pulsed light of an ArF laser (193 nm): a new luminescence with two bands -- a blue one associated to a time constant of about 100 μs appears and another one wit…
Ultraviolet optical properties of silica controlled by hydrogen trapping at Ge-related defects
2007
We studied the effects induced by the ultraviolet-laser and -lamp exposure sequences on the twofold coordinated germanium (=Ge{sup {center_dot}}{sup {center_dot}}) and the H(II) center (=Ge{sup {center_dot}}-H) in silica. The H(II) centers, generated after the first laser irradiation stage by the trapping of atomic hydrogen H{sup 0} at the (=Ge{sup {center_dot}}{sup {center_dot}}), are destroyed by the subsequent lamp exposure with efficiency depending on photon energy. The H(II) photodestruction is activated from {approx}4 eV, and its cross section is here quantitatively measured, so giving the absorption profile of this center. Consistent with the observed correlated recovering of (=Ge{su…
Toxicity of tebufenozide, an ecdysteroid agonist, to [i]Blattella germanica[/i] (Blattodea: Blattellidae)
2014
The toxicity of the non-steroidal ecdysteroid agonist tebufenozide was evaluated topically on adults of the cosmopolitan cockroach Blattella germanica (Blattodea: Blattellidae). The LD50 value was estimated at 402 mu g/g of insect (range, 95% fiducial limits: 293-552) at 15 days after treatment. The effects on reproduction were observed in adult females of cockroaches that survived exposure to a LD25 (146 mu g/g of insect) of tebufenozide. Dissection of treated females showed a clear reduction in both the number of oocytes per paired ovaries and the size of basal oocytes, as compared to controls. In addition, tebufenozide significantly reduced the mating success of pairs and altered the fer…
Effet insecticide de Bacillus thuringiensis kurstaki et d’une toxine bactérienne, le Spinosad, à l’égard des blattes domestiques adultes (Blattella g…
2012
Les blattes sont très étudiées en raison de leur impact sur la santé humaine et animale, sur les cultures et l’habitat. Blattella germanica est une blatte domestique prédominante qui représente un vecteur potentiel des maladies. En raison de sa nuisance elle a fait l’objet de plusieurs études, en vue d’une lutte efficace. Ces dernières années, une nouvelle approche toxicologique est apparue, elle consiste à développer de nouveaux insecticides issus essentiellement des molécules biologiques telles que les plantes et les microorganismes comme les champignons et les bactéries. Dans cette étude on s’est intéressé aux effets induits par le Bacillus thuringiensiskurstaki sur les adultes de B. ger…