Idar-Oberstein, Germany
Idar-Oberstein, Germany
Time filter
Source Type

Douissard P.-A.,European Synchrotron Radiation Facility | Cecilia A.,Karlsruhe Institute of Technology | Martin T.,European Synchrotron Radiation Facility | Chevalier V.,European Synchrotron Radiation Facility | And 6 more authors.
Journal of Synchrotron Radiation | Year: 2010

The efficiency of high-resolution pixel detectors for hard X-rays is nowadays one of the major criteria which drives the feasibility of imaging experiments and in general the performance of an experimental station for synchrotron-based microtomography and radiography. Here the luminescent screen used for the indirect detection is focused on in order to increase the detective quantum efficiency: a novel scintillator based on doped Lu2SiO5 (LSO), epitaxially grown as thin film via the liquid phase epitaxy technique. It is shown that, by using adapted growth and doping parameters as well as a dedicated substrate, the scintillation behaviour of a LSO-based thin crystal together with the high stopping power of the material allows for high-performance indirect X-ray detection. In detail, the conversion efficiency, the radioluminescence spectra, the optical absorption spectra under UV/visible-light and the afterglow are investigated. A set-up to study the effect of the thin-film scintillators temperature on its conversion efficiency is described as well. It delivers knowledge which is important when working with higher photon flux densities and the corresponding high heat load on the material. Additionally, X-ray imaging systems based on different diffraction-limited visible-light optics and CCD cameras using among others LSO-based thin film are compared. Finally, the performance of the LSO thin film is illustrated by imaging a honey bee leg, demonstrating the value of efficient high-resolution computed tomography for life sciences. © 2010 International Union of Crystallography.

Druon F.,University Paris - Sud | Velazquez M.,CNRS Laboratory of Condensed Matter Chemistry, Bordeaux | Veber P.,CNRS Laboratory of Condensed Matter Chemistry, Bordeaux | Janicot S.,University Paris - Sud | And 6 more authors.
Optics Letters | Year: 2013

We present, to the best of our knowledge, the first laser demonstration of an Yb-doped Gd2O3 cubic crystal. This crystal was obtained by the flux method using an original borate-based solvent, which was particularly well suited to the growth of rare earth sesquioxide crystals at half the working temperature of classical growth techniques. This flux method is a very interesting alternative for the production of laser sesquioxide crystals, not only because it provides access to new matrices of the cubic polymorph, but also because it permits high Yb3+-doping levels for these crystals. The first laser results of two highly Yb3+-doped sesquioxides, namely Gd2O3 and Y2O3, grown by this flux method are presented here, including the Ti:sapphire and diode pumping configurations. Laser efficiencies and emission spectra for these two crystals were studied and compared. © 2013 Optical Society of America.

Daniels J.E.,University of New South Wales | Jo W.,TU Darmstadt | Rodel J.,TU Darmstadt | Rytz D.,FEE GmbH | Donner W.,TU Darmstadt
Applied Physics Letters | Year: 2011

Diffuse x-ray scattering intensities from a single crystal of 0.96 (Bi 1/2 Na1/2 TiO3) -0.04 (BaTiO3) have been collected at room temperature with and without application of an electric field along the [100] direction. Distinct features in the diffuse scattering intensities indicate correlations on a nanometer length scale. It is shown that locally correlated planar-like structures and octahedral tilt-domains within the room temperature rhombohedral R3c phase are both electrically active and are irreversibly affected by application of an electric field of 4.3 kV/mm. The field dependence of these nanoscale structures is correlated with the relaxor behavior of the material by macroscopic permittivity measurements. © 2011 American Institute of Physics.

Ricaud S.,University Paris - Sud | Ricaud S.,Amplitude Systemes | Jaffres A.,Chimie Paristech | Wentsch K.,University of Stuttgart | And 12 more authors.
Optics Letters | Year: 2012

A mode-locked thin-disk laser based on Yb:CALGO is demonstrated for the first time. At an average output power of 28 W we obtained pulses with a duration of 300 fs and a pulse energy of 1.3 μJ. 197 fs pulses with 0.9 μJ of energy were achieved at an average output power of 20 W. The shortest pulse duration measured in our experiments was 135 fs with a spectrum centered at 1043 nm. The experiments also revealed a very broad tunability from 1032 to 1046 nm with sub-200 fs pulses. © 2012 Optical Society of America.

Schneider D.,TU Darmstadt | Rodel J.,TU Darmstadt | Rytz D.,FEE GmbH | Granzow T.,Luxembourg Institute of Science and Technology LIST
Journal of the American Ceramic Society | Year: 2015

The direction-dependence of pyroelectric properties of (1 - x)Bi1/2Na1/2TiO3 - xBaTiO3 (BNT - 100xBT) is investigated, using single crystal samples with well-defined orientations for x = 0.036 and x = 0.063. The results are compared with those of temperature-dependent measurements of the ferroelectric and dielectric hysteresis. The depolarization temperature Td of each crystal composition is found to depend on crystal orientation, a fact that is explained by differences in the stability of respective domain configurations. A rationalization is offered for the observation that Td differs from the ferroelectric-relaxor transition temperature, depending on orientation. The hysteresis curves of BNT - 3.6BT are typical for a rhombohedral system with a ferroelectric-relaxor transition, with polarization reversal close to Td occurring in a multistep process that includes decay of ferroelectric domains into polar nanoregions and re-formation of domains. BNT - 6.3BT, a composition in the region of the morphotropic phase boundary, shows the same feature, but additionally is characterized by a field-induced transition between rhombohedral and tetragonal symmetry. This combination results in an effective piezoelectric coefficient of d33∗=1886 pm/V. © 2015 The American Ceramic Society.

Le Dantec R.,University of Savoy | Mugnier Y.,University of Savoy | Djanta G.,University of Savoy | Bonacina L.,University of Geneva | And 7 more authors.
Journal of Physical Chemistry C | Year: 2011

Hyper Rayleigh scattering (HRS) and second harmonic (SH) microscopy were used to study the second order nonlinear optical response of ZnO and BaTiO 3 nanocrystals, which have been recently proposed as new markers for bioimaging. HRS, combined with dynamic light scattering, was first used to retrieve hyperpolarizabilities and nonlinear coefficients of both type of nanocrystals. The results indicate that the main contribution to the SH signal is related to the bulk noncentrosymmetric structure of the particles. Successively, we carried out the inspection of individual nanocrystals by SH microscopy, interpreting their response using the nonlinear coefficients deduced from HRS. © 2011 American Chemical Society.

Cattoor R.,French National Center for Scientific Research | Cattoor R.,French German Research Institute of Saint Louis | Manek-Honninger I.,French National Center for Scientific Research | Rytz D.,FEE GmbH | And 2 more authors.
Optics Letters | Year: 2014

Wedemonstrate the first (to our knowledge) quasi-three-level conical refraction laser operating at 2 μm, with 1.6Wof output power at 2074 nm, using a holmium-doped KY(WO4)2 crystal. A maximum slope efficiency of 52% has been achieved, along the optic axis with respect to the absorbed pump power. Furthermore, lasing operation around the optic axis has been performed. In this case, a maximumoutput power of 3Whas been reached, with a slope efficiency better than 70%, which are the best performances ever reported on this material. © 2014 Optical Society of America.

Staedler D.,Ecole Polytechnique Federale de Lausanne | Magouroux T.,University of Geneva | Passemard S.,Ecole Polytechnique Federale de Lausanne | Schwung S.,FEE Gmbh | And 6 more authors.
Nanoscale | Year: 2014

A biophotonics approach based on the nonlinear optical process of second harmonic generation is presented and demonstrated on malignant human cell lines labelled by harmonic nanoparticles. The method enables independent imaging and therapeutic action, selecting each modality by simply tuning the excitation laser wavelength from infrared to visible. In particular, the generation of deep ultraviolet radiation at 270 nm allows direct interaction with nuclear DNA in the absence of photosensitizing molecules. © 2014 The Royal Society of Chemistry.

Staedler D.,Ecole Polytechnique Federale de Lausanne | Magouroux T.,University of Geneva | Hadji R.,University of Savoy | Joulaud C.,University of Savoy | And 15 more authors.
ACS Nano | Year: 2012

Nonlinear optical nanocrystals have been recently introduced as a promising alternative to fluorescent probes for multiphoton microscopy. We present for the first time a complete survey of the properties of five nanomaterials (KNbO 3, LiNbO 3, BaTiO 3, KTP, and ZnO), describing their preparation and stabilization and providing quantitative estimations of their nonlinear optical response. In the light of their prospective use as biological and clinical markers, we assess their biocompatibility on human healthy and cancerous cell lines. Finally, we demonstrate the great potential for cell imaging of these inherently nonlinear probes in terms of optical contrast, wavelength flexibility, and signal photostability. © 2012 American Chemical Society.

Veber P.,CNRS Laboratory of Condensed Matter Chemistry, Bordeaux | Velazquez M.,CNRS Laboratory of Condensed Matter Chemistry, Bordeaux | Gadret G.,Laboratory Interdisciplinaire Carnot de Bourgogne | Rytz D.,FEE GmbH | And 2 more authors.
CrystEngComm | Year: 2014

In this work, we present the first crystal growth of cubic Tb2O3 single crystals by a controlled atmosphere flux method which uses a heavy metal free solvent working at less than half the melting temperature of this sesquioxide. Cubic millimeter-sized crystals extracted from as-grown boules are phase (powder XRD) and chemically (GDMS) pure and exhibit a Verdet constant in the visible and near-infrared spectral ranges, which is at least three times higher than that of a commercial Tb3Ga5O12 (TGG) crystal. The 1.36 mm thick crystals display a transmission coefficient higher than 77% over the 525 nm-1.38 μm spectral range. The absorption spectrum, magnetic susceptibility and specific heat measurements on the single crystals confirm the absence of detectable Tb4+ cations and other impurities. This journal is © The Royal Society of Chemistry.

Loading FEE GmbH collaborators
Loading FEE GmbH collaborators