ORCID Profile
0000-0003-3508-4219
Current Organisation
CNRS Délégation Côte d'Azur
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Publisher: AIP Publishing
Date: 28-10-2003
DOI: 10.1063/1.1619553
Abstract: A fiber-optic sensing scheme for the simultaneous measurement of strain and a wide range of temperatures has been investigated by combining the properties of the fiber Bragg grating (FBG) and the fluorescence from a rare-earth-doped photosensitive fiber. The temperature-dependent fluorescence peak power ratio of the two peaks occurring around 1535 nm and 1552 nm from the lified spontaneous emission due to the I13/24↔4I15/2 transitions in Er3+-doped tin–germanosilicate fiber, with 980 nm pumping, and the dual functionality of the FBG were exploited in this scheme. The sensor is based on a single FBG written in a small length (∼10 cm) of the above fiber, which can be used for the simultaneous measurement of strain and temperature over ranges of 0–1150 με and 22–500 °C, with root-mean-square errors of 36 με and 6 °C, respectively.
Publisher: The Optical Society
Date: 21-08-2008
DOI: 10.1364/OE.16.013781
Abstract: The spectroscopic properties of Tm(3+)/Yb(3+) co-doped silica fibers under excitation at 980 nm are reported. Three distinct up-conversion fluorescence bands were observed in the visible to near infra-red regions. The blue and red fluorescence bands at 475 and 650 nm, respectively, were found to originate from the (1)G(4) level of Tm(3+). A three step up-conversion process was established as the populating mechanism for these fluorescence bands. The fluorescence band at 800 nm was found to originate from two possible transitions in Tm(3+) one being the transition from the (3)H(4) to (3)H(6) manifold which was found to dominate at low pump powers the other being the transition from the (1)G(4) to (3)H(6) level which dominates at higher pump powers. The fluorescence lifetime of the (3)H(4) and (3)F(4) levels of Tm(3+) and (2)F(5/2) level of Yb(3+) were studied as a function of Yb(3+) concentration, with no significant energy back transfer from Tm(3+) to Yb(3+) observed.
Publisher: Elsevier BV
Date: 02-2006
Publisher: SPIE
Date: 07-02-2006
DOI: 10.1117/12.675682
Publisher: IOP Publishing
Date: 14-05-2004
Publisher: IEEE
Date: 06-2007
Publisher: Elsevier BV
Date: 07-2004
Publisher: SPIE
Date: 03-06-2005
DOI: 10.1117/12.606166
Publisher: Optica Publishing Group
Date: 08-2004
Abstract: Bragg gratings were fabricated in an Sn-Er-Ge-codoped silica fiber with a phase mask and ultraviolet radiation from a 248-nm KrF excimer laser. The photosensitivity of the fiber was examined by studying the initial growth rate of the gratings written into it. The thermal stability of the gratings was investigated and modeled in terms of both the refractive-index modulation and the effective refractive index of the fiber core. It was shown that the temperature-induced irreversible shift in the Bragg wavelength could not be predicted by the isothermal decay of the refractive-index modulation. Finally, the potential of the gratings written into the fiber is discussed in terms of their use in high-temperature-sensing applications.
Publisher: The Optical Society
Date: 07-1994
DOI: 10.1364/OL.19.000990
Abstract: We present a spectroscopic study of the green fluorescence resulting from pump excited-state absorption in Er-doped silica fibers excited in the 800-nm range. The absorption and emission bands are selectively attributed to the (4)S(3/2) and (2)H(11/2) levels. The fluorescence response at two excitation wavelengths, the temperature behavior, and lifetime measurements demonstrate a fast thermalization between the (4)S(3/2) and (2)H(11/2) levels. This explains an important part of the (2)H(11/2) emission and the increase of the fluorescence intensity at high temperature.
Publisher: Copernicus GmbH
Date: 06-11-2014
DOI: 10.5194/ACP-14-11633-2014
Abstract: Abstract. During the July 2011 Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field experiment in Maryland, significant enhancements in Aerosol Robotic Network (AERONET) sun–sky radiometer measured aerosol optical depth (AOD) were observed in the immediate vicinity of non-precipitating cumulus clouds on some days. Both measured Ångström exponents and aerosol size distribution retrievals made before, during and after cumulus development often suggest little change in fine mode particle size therefore, implying possible new particle formation in addition to cloud processing and humidification of existing particles. In addition to sun–sky radiometer measurements of large enhancements of fine mode AOD, lidar measurements made from both ground-based and aircraft-based instruments during the experiment also measured large increases in aerosol signal at altitudes associated with the presence of fair weather cumulus clouds. These data show modifications of the aerosol vertical profile as a result of the aerosol enhancements at and below cloud altitudes. The airborne lidar data were utilized to estimate the spatial extent of these aerosol enhancements, finding increased AOD, backscatter and extinction out to 2.5 km distance from the cloud edge. Furthermore, in situ measurements made from aircraft vertical profiles over an AERONET site during the experiment also showed large increases in aerosol scattering and aerosol volume after cloud formation as compared to before. The 15-year AERONET database of AOD measurements at the Goddard Space Flight Center (GSFC), Maryland site, was investigated in order to obtain a climatological perspective of this phenomenon of AOD enhancement. Analysis of the diurnal cycle of AOD in summer showed significant increases in AOD from morning to late afternoon, corresponding to the diurnal cycle of cumulus development.
Publisher: Elsevier BV
Date: 05-2004
Publisher: AIP Publishing
Date: 26-04-2004
DOI: 10.1063/1.1711155
Abstract: A simple and effective technique for strain-independent temperature measurement has been demonstrated using the peak wavelengths of both type-I and type-IIA fiber Bragg gratings written without hydrogen loading in the same fiber, this having been specially fabricated with a high concentration of germanium in the core composition. The device is also capable of monitoring strain and temperature simultaneously and can be used to measure temperature over the range of 25–300 °C with a strain range of 0–500 με, achieving a temperature-dependent sensitivity of 0.53 and 0.31 pm/°C for strain-independent temperature measurement with root mean square errors of 2.4 and 4.1 °C at 25 and 300 °C, respectively.
Publisher: SPIE
Date: 17-11-2008
DOI: 10.1117/12.818042
Publisher: Copernicus GmbH
Date: 17-07-2014
DOI: 10.5194/ACPD-14-18785-2014
Abstract: Abstract. During the July 2011 DISCOVER-AQ field experiment in Maryland, significant enhancements in AERONET sun-sky radiometer measured AOD were observed in the immediate vicinity of non-precipitating cumulus clouds on some days. Both measured Angstrom exponents and aerosol size distribution retrievals made before, during and after cumulus development often suggest little change in fine mode particle size, therefore implying possible new particle formation in addition to cloud processing and humidification of existing particles. In addition to sun/sky radiometer measurements of large enhancements of fine mode AOD, lidar measurements made from both ground-based and aircraft-based instruments during the experiment also measured large increases in aerosol signal at altitudes associated with the presence of fair weather cumulus clouds. These data show modifications of the aerosol vertical profile as a result of the aerosol enhancements at and below cloud altitudes. The airborne lidar data were utilized to estimate the spatial extent of these aerosol enhancements, finding increased AOD, backscatter and extinction out to 2.5 km distance from the cloud edge. Furthermore, in situ measurements made from aircraft vertical profiles over an AERONET site during the experiment also showed large increases in aerosol scattering and aerosol volume after cloud formation as compared to before. The 15 year AERONET database of AOD measurements at the GSFC, Maryland site was investigated in order to obtain a climatological perspective of this phenomenon of AOD enhancement. Analysis of the diurnal cycle of AOD in summer showed significant increases in AOD from morning until late afternoon, corresponding to the diurnal cycle of cumulus development.
Publisher: Elsevier BV
Date: 07-1996
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Bernard Dussardier.