0000000001180167
AUTHOR
J. Mangin
showing 16 related works from this author
Study of the pyroelectricity in LiIns2 crystal
2002
Abstract Pyroelectric current measurements performed on a LiInS2 monodomain single crystal show a linear variation of the current between 120 and 260 K. Near room temperature, a space charge relaxation screens pyroelectricity. The pyroelectric coefficient follows a linear thermal dependence leading to an extrapolated value of 6×10−10 C K−1 cm−2 at 300 K. As for other oxide-type pyroelectric compounds, this value is shown to be proportional to the electro-optic coefficient r333 of LiInS2.
PtTe2: Potential new material for the growth of defect-free TeO2 single crystals
2008
Abstract The dissociation of Te–O bonds is the main drawback, which hampers the yield of large-sized paratellurite single crystals of high optical quality when using platinum crucibles. In this work, it is assumed that a catalytic dissociation process involves the intermediate formation of platinum tellurides, these ones being then responsible for entrapment of gas bubbles and black precipitates when growth proceeds. To alleviate this difficulty, we suggest that platinum ditelluride could be a chemically more appropriate compound instead of pure platinum. First experiments on direct transformation of platinum sheets into PtTe 2 under tellurium gas atmosphere are described, as well as the pr…
Comprehensive formulation of temperature-dependent dispersion of optical materials: illustration with case of temperature tuning of a mid-IR HgGa_2S_…
2009
The temperature dependence of refractive indices of optical materials is characterized in this work by what we call their normalized thermo-optic coefficients. These are determined experimentally through interferometric measurements of thermal expansion and of changes in optical thickness at a few laser wavelengths as function of temperature. A suitable vectorial formalism applied to these data allows predicting the thermal evolution of the refractive index all over the useful range of transparency. The validity and reliability of our methodology is demonstrated through temperature tuning of a mid-IR HgGa2S4 optical parametric oscillator (OPO) pumped at 1.0642 μm by a Nd:YAG laser. Measured…
Optical characterization of YCa4O(BO3)3 and Nd:YCa4O(BO3)3 crystals
2007
International audience; We report a complete optical characterization of YCa4O(BO3)3 and Nd:YCa4O(BO3)3 crystals. We studied the relative orientation between the dielectric and the crystallographic frames as a function of the wavelength and performed accurate phase-matching angles measurements for second harmonic generation, using a single crystal cut as a sphere. We also recorded polarized luminescence spectra of Nd:YCOB along the principal axes of the dielectric frame. For both crystals, we measured the gray-tracking and the thermo-optic properties as a function of temperature and wavelength using oriented slabs. Finally, we measured all their dielectric and electro-optic coefficients, as…
Bridgman growth of paratellurite single crystals
2004
Abstract The growth of paratellurite single crystals by the vertical-gradient freezing technique is reported for the first time. Boules of 120 mm long and 25 mm in diameter were obtained under a temperature gradient of 10°C cm −1 and translation rates lower than 0.6 mm h −1 . The spatial distribution of defects along the growth axis reveals a continuous evolution of the free convective fluid-flow regime as growth proceeds. Gas bubbles and dark inclusions rejected to the periphery in the upper part of the crystal are observed to lay preferentially in (1 0 0), (0 0 1), ( 1 1 ¯ 0 ) and (1 1 2) crystallographic planes. Among them, SEM and microprobe analyses evidenced the presence of metallic p…
Interpretation of the Anomalous NaI Events
2001
Anomalous events, with scintillation decay times shorter than nuclear recoils, have been observed by the UKDMC and Saclay NaI experiments. By using the event categories observed in the EDELWEISS experiment, we propose to interpret the anomalous NaI events as surface nuclear recoils accompanied with a small energy loss of an escaping alpha particle. The discrimination performances of the NaI experiments which have not taken into account these events in their analysis, notably for axial WIMP interactions, must then be reevaluated.
TeO2 liquid phase: Viscosity measurements and evaluation of the thermal conductivity from crystal growth experiments
2008
Current applications of paratellurite TeO{sub 2} in optics and nuclear physics require improving the yield and optical quality of synthesized single crystals. Modelling of the growth process is a useful tool for such purpose, however, involving the knowledge of several thermodynamic parameters of both solid and liquid phase of the compound. This work describes the determination of two main unknown ones, namely dynamic viscosity {eta} and thermal conductivity {lambda}{sub l} of the liquid phase. Measurements of {eta} are performed by means of a specifically designed apparatus; over a 40 K temperature interval above the melting point we find a mean value of 0.028 Pa.s. This data is used in co…
Status of the EDELWEISS experiment
1999
The Edelweiss Dark Matter Experiment is installed in the Modane Underground Laboratory since 1994. In 1997 the first detector of a 70 g heat and ionization Ge low-temperature detector built by the collaboration showed its discrimination capabilities. During the last two years the installation was upgraded, and a new generation of 70 g Ge detectors is operational. The detector environment is drastically controlled to avoid radioactive contamination. A test run with two new 70 g detectors shows a reduction by a factor of ten in the background level before 7-ray rejection which is now around 2 events/kg/keV/day. Three 320 g Ge cryogenic detectors have been constructed and are now being tested …
Thermal expansion, normalized thermo-optic coefficients, and condition for second harmonic generation of a Nd:YAG laser with wide temperature bandwid…
2011
Interferometric determination of thermal expansion and of normalized thermo-optic coefficients of RbTiOPO4 at four laser wavelengths are performed as a function of temperature. A suitable vectorial formalism applied to obtained data allows the establishment of the temperature dependence of refractive indices, and subsequent theoretical analysis enables one to predict that an extremum in the evolution of the phase-matching direction in the (X,Y) plane should occur near 100 °C for type II second harmonic generation of Nd:YAG lasers, with a temperature bandwidth that can be as large as 117 °C for a crystal of 10 mm in length. Such unusual behavior is observed experimentally by recording the co…
Métrologie des propriétés optiques de matériaux massifs : absorption résiduelle, coefficients thermo-optiques, piézo-électriques et électro-optiques
2003
Resume. Cet article presente quelques methodes experimentales mises en œuvre pour determiner de la facon la plus precise possible quelques proprietes importantes des materiaux optiques massifs. Les grandeurs examinees ici sont l’absorption residuelle, les coefficients thermo-optiques, electro-optiques et piezo-electriques. L’accent est mis en particulier sur des techniques de type photo-acoustique pour l’obtention du premier parametre et sur le developpement de techniques interferometriques specifiques pour la mesure des trois autres coefficients.
Accordabilité thermique des interactions ONL: formalisme vectoriel et applications à HGS, KTP et RTP
2007
National audience
Thiogallate de mercure (HgGa2S4) : un cristal pour les OPO dans le moyen infrarouge
2007
Comprehensive formulation of the temperature dependent dispersion of optical materials; illustration with the case of temperature tuning of a mid-IR …
2009
International audience; The temperature dependence of refractive indices of optical materials is characterized in this work by what we call their normalized thermo-optic coefficients. These ones are determined experimentally through interferometric measurements of thermal expansion, and changes in optical thickness at a few laser wavelengths as function of temperature. A suitable vectorial formalism applied to these data allows predicting the thermal evolution of the refractive index all over the useful range of transparency. The validity and reliability of our methodology is demonstrated through temperature tuning of a mid-IR HgGa2S4 OPO, pumped at 1.0642 μm by a Nd:YAG laser. Measured the…
Background discrimination capabilities of a heat and ionization germanium cryogenic detector
2001
The discrimination capabilities of a 70 g heat and ionization Ge bolometer are studied. This first prototype has been used by the EDELWEISS Dark Matter experiment, installed in the Laboratoire Souterrain de Modane, for direct detection of WIMPs. Gamma and neutron calibrations demonstrate that this type of detector is able to reject more than 99.6% of the background while retaining 95% of the signal, provided that the background events distribution is not biased towards the surface of the Ge crystal. However, the 1.17 kg.day of data taken in a relatively important radioactive environment show an extra population slightly overlapping the signal. This background is likely due to interactions o…