Search results for " Optics"
showing 10 items of 5880 documents
Birefringent porous silicon membranes for optical sensing
2012
In this work anisotropic porous silicon is investigated as a material for optical sensing. Birefringence and sensitivity of the anisotropic porous silicon membranes are thoroughly studied in the framework of Bruggeman model which is extended to incorporate the influence of environment effects, such as silicon oxidation. The membranes were also characterized optically demonstrating sensitivity as high as 1245 nm/RIU at 1500 nm. This experimental value only agrees with the theory when it takes into consideration the effect of silicon oxidation. Furthermore we demonstrate that oxidized porous silicon membranes have optical parameters with long term stability. Finally, we developed a new model …
Octave Spanning Supercontinuum in Titanium Dioxide Waveguides
2018
International audience; We report on the experimental generation of an octave-spanning supercontinuum in a 2.2 cm-long titanium dioxide optical waveguide with two zero dispersion wavelengths. The resulting on-chip supercontinuum reaches the visible wavelength range as well as the mid-infrared region by using a femtosecond fiber laser pump at 1.64 µm.
Distribution and generation of traps in SiO2/Al2O3 gate stacks
2007
In this work we combine charge-pumping measurements with positive constant voltage stress to investigate trap generation in SiO2/ Al2O3 n-MOSFET. Trap density has been scanned either in energy or in position based on charge-pumping (CP) measurements performed under different operating conditions in terms of amplitude and frequency of the gate pulse. Our results have revealed that the traps are meanly localized shallow in energy level, deeper in spatial position and they are mostly generated near the Si/SiO2 interface. (C) 2007 Elsevier Ltd. All rights reserved.
Age-Related Differences in Intermuscular Coherence EMG-EMG of Ankle Joint Antagonist Muscle Activity during Maximal Leaning
2022
Background: Intermuscular synchronization is one of the fundamental aspects of maintaining a stable posture and is of great importance in the aging process. This study aimed to assess muscle synchronization and postural stabilizer asymmetry during quiet standing and the limits of stability using wavelet analysis. Intermuscular synchrony and antagonistic sEMG-sEMG (surface electromyography) coherence asymmetry were evaluated in the tibialis anterior and soleus muscles. Methods: The study involved 20 elderly (aged 65 ± 3.6) and 20 young (aged 21 ± 1.3) subjects. The task was to perform a maximum forward bend in a standing position. The prone test was divided into three phases: quiet standing …
Trap-assisted studies of odd, neutron-rich isotopes from Tc to Pd
2012
We review the present and future of trap-assisted structure studies of odd, neutron-rich Tc, Ru, Rh and Pd isotopes at the limits of present experimental techniques. These nuclei of refractory elements are produced in light-particle induced fission and filtered by their mass number with the IGISOL mass separator. Further mass separation with the JYFLTRAP Penning trap system provides a clean, monoisotopic beam perfectly suited for precise nuclear spectroscopy. Connecting the IGISOL and the JYFLTRAP facilities to the recently installed MCC30/15 cyclotron opens new prospects for post-trap spectroscopy of very exotic, neutron-rich nuclei. peerReviewed
The ion-optical design of the MARA recoil separator and absolute transmission measurements of the RITU gas-filled recoil separator
2011
In this thesis work, the use of two complementary recoil separators for studies of nuclear structure via fusion-evaporation reactions are discussed. The design and the main ion-optical properties of the vacuum-mode recoil-mass separator MARA, intended for studies of nuclei with N Z close to the proton drip-line, are presented. MARA (Mass Analysing Recoil Apparatus) consists of a magnetic quadrupole triplet followed by an electrostatic de ector and a magnetic dipole. The working principle of MARA is discussed and the reasons for the choice of the optical parameters of the elements are given. The performance of MARA for di erent kind of fusion reactions has been studied with Monte Carlo simul…
Dynamics of Metal Centers Monitored by Nuclear Inelastic Scattering
2005
Nuclear inelastic scattering of synchrotron radiation has been used now since 10 years as a tool for vibrational spectroscopy. This method has turned out especially useful in case of large molecules that contain a M\"ossbauer active metal center. Recent applications to iron-sulfur proteins, to iron(II) spin crossover complexes and to tin-DNA complexes are discussed. Special emphasis is given to the combination of nuclear inelastic scattering and density functional calculations.
Optical Fiber Based Dosimeter Data From RADEF Pulsed Electron Beams - Oscilloscope Traces
2021
These data are from tests of fiber optic based dosimetry systems. The purpose of the collected data is to use it for characterizing the different tested samples responses against pulsed electron radiation, for different electron bunch sizes. The tested samples are sol-gel silica glass rods doped with Ce, Cu, or Gd ions, making the rods radioluminescent. The samples were connected to a multimode pure-silica core optical fiber, which transported the radiation induced luminescence (RIL) to a photomultiplier tube (PMT) with an optical band pass filter in front of it. The samples were subject to a pulsed 20 MeV electron beam. The resulting output pulses from the PMT from the induced RIL light we…
Flat bands, Dirac cones, and atom dynamics in an optical lattice
2010
We study atoms trapped with a harmonic confinement in an optical lattice characterized by a flat band and Dirac cones. We show that such an optical lattice can be constructed which can be accurately described with the tight binding or Hubbard models. In the case of fermions the release of the harmonic confinement removes fast atoms occupying the Dirac cones while those occupying the flat band remain immobile. Using exact diagonalization and dynamics we demonstrate that a similar strong occupation of the flat band does not happen in bosonic case and furthermore that the mean field model is not capable for describing the dynamics of the boson cloud.
Indo-French High-resolution Thermal Infrared Space Mission for Earth Natural Resources Assessment and Monitoring -Concept and Definition of TRISHNA
2019
The Indian and French Space Agencies, ISRO and CNES, have conceptualized a space-borne Thermal Infrared Reflectance (TIR) mission, TRISHNA (Thermal infRared Imaging Satellite for High-resolution Natural Resource Assessment). The primary design drivers of TRISHNA are the monitoring of (i) terrestrial water stress and use, and of (ii) coastal and continental water. A suit of four TIR bands and six optical bands is planned. The TIR bands will be centred at 8.6 μm, 9.1 μm, 10.3 μm and 11.5 μm to provide noon-night global observations at 57m nadir resolution over land and coastal regions. The field of view (FOV) is ±34° and the orbit of 761&thin…