The Experts below are selected from a list of 25812 Experts worldwide ranked by ideXlab platform
Denise M. Krol - One of the best experts on this subject based on the ideXlab platform.
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femtosecond laser writing of waveguides in zinc phosphate glasses invited
Optical Materials Express, 2011Co-Authors: L B Fletcher, Jonathan J Witcher, Neil Troy, Signo Tadeu Dos Reis, Richard K Brow, Rebeca Martinez Vazquez, Roberto Osellame, Denise M. KrolAbstract:We have studied the relationship between the initial glass composition and the structural changes associated with laser-induced refractive index modification in a series of Er-Yb doped and undoped zinc phosphate glasses. White light microscopy and waveguide experiments are used together with Raman and fluorescence spectroscopy to characterize the structural changes. The correlation between Raman Peak shifts and fluorescence from phosphorus–oxygen hole center (POHC) defects indicates that fs-laser writing results in a depolymerization of the phosphate glass network. The results also show that the exact glass composition should be taken into account when fabricating waveguide devices in phosphate glasses, in order to both expand the fs-laser processing conditions and maximize favorable morphological changes for 3-D photonic devices.
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changes to the network structure of er yb doped phosphate glass induced by femtosecond laser pulses
Journal of Applied Physics, 2009Co-Authors: L B Fletcher, Jon J Witcher, Wilbur B Reichman, Alan Arai, Jim Bovatsek, Denise M. KrolAbstract:Changes to the glass network structure after modification with tightly focused 1043nm, 400fs laser pulses have been studied in Er–Yb doped phosphate glass using in situ confocal Raman microscopy. For femtosecond laser writing conditions that result in heat accumulation, the 710 and 1209cm−1 Raman Peaks, which are due to the (POP)sym and (PO2)sym network vibration modes, respectively, shift to both higher and lower wavenumbers. The differences in refractive index are shown to correlate spatially with the 1209cm−1 Raman signal shifts. Systematic shifts in this Raman Peak to higher and lower wavenumbers indicate an overall expansion and/or contraction of the phosphate network that depends on the femtosecond laser writing conditions.
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changes to the network structure of er yb doped phosphate glass induced by femtosecond laser pulses
Journal of Applied Physics, 2009Co-Authors: L B Fletcher, Jon J Witcher, Wilbur B Reichman, Alan Arai, Jim Bovatsek, Denise M. KrolAbstract:Changes to the glass network structure after modification with tightly focused 1043nm, 400fs laser pulses have been studied in Er–Yb doped phosphate glass using in situ confocal Raman microscopy. For femtosecond laser writing conditions that result in heat accumulation, the 710 and 1209cm−1 Raman Peaks, which are due to the (POP)sym and (PO2)sym network vibration modes, respectively, shift to both higher and lower wavenumbers. The differences in refractive index are shown to correlate spatially with the 1209cm−1 Raman signal shifts. Systematic shifts in this Raman Peak to higher and lower wavenumbers indicate an overall expansion and/or contraction of the phosphate network that depends on the femtosecond laser writing conditions.
L B Fletcher - One of the best experts on this subject based on the ideXlab platform.
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femtosecond laser writing of waveguides in zinc phosphate glasses invited
Optical Materials Express, 2011Co-Authors: L B Fletcher, Jonathan J Witcher, Neil Troy, Signo Tadeu Dos Reis, Richard K Brow, Rebeca Martinez Vazquez, Roberto Osellame, Denise M. KrolAbstract:We have studied the relationship between the initial glass composition and the structural changes associated with laser-induced refractive index modification in a series of Er-Yb doped and undoped zinc phosphate glasses. White light microscopy and waveguide experiments are used together with Raman and fluorescence spectroscopy to characterize the structural changes. The correlation between Raman Peak shifts and fluorescence from phosphorus–oxygen hole center (POHC) defects indicates that fs-laser writing results in a depolymerization of the phosphate glass network. The results also show that the exact glass composition should be taken into account when fabricating waveguide devices in phosphate glasses, in order to both expand the fs-laser processing conditions and maximize favorable morphological changes for 3-D photonic devices.
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changes to the network structure of er yb doped phosphate glass induced by femtosecond laser pulses
Journal of Applied Physics, 2009Co-Authors: L B Fletcher, Jon J Witcher, Wilbur B Reichman, Alan Arai, Jim Bovatsek, Denise M. KrolAbstract:Changes to the glass network structure after modification with tightly focused 1043nm, 400fs laser pulses have been studied in Er–Yb doped phosphate glass using in situ confocal Raman microscopy. For femtosecond laser writing conditions that result in heat accumulation, the 710 and 1209cm−1 Raman Peaks, which are due to the (POP)sym and (PO2)sym network vibration modes, respectively, shift to both higher and lower wavenumbers. The differences in refractive index are shown to correlate spatially with the 1209cm−1 Raman signal shifts. Systematic shifts in this Raman Peak to higher and lower wavenumbers indicate an overall expansion and/or contraction of the phosphate network that depends on the femtosecond laser writing conditions.
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changes to the network structure of er yb doped phosphate glass induced by femtosecond laser pulses
Journal of Applied Physics, 2009Co-Authors: L B Fletcher, Jon J Witcher, Wilbur B Reichman, Alan Arai, Jim Bovatsek, Denise M. KrolAbstract:Changes to the glass network structure after modification with tightly focused 1043nm, 400fs laser pulses have been studied in Er–Yb doped phosphate glass using in situ confocal Raman microscopy. For femtosecond laser writing conditions that result in heat accumulation, the 710 and 1209cm−1 Raman Peaks, which are due to the (POP)sym and (PO2)sym network vibration modes, respectively, shift to both higher and lower wavenumbers. The differences in refractive index are shown to correlate spatially with the 1209cm−1 Raman signal shifts. Systematic shifts in this Raman Peak to higher and lower wavenumbers indicate an overall expansion and/or contraction of the phosphate network that depends on the femtosecond laser writing conditions.
Ludger Wirtz - One of the best experts on this subject based on the ideXlab platform.
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anomalous quantum confinement of the longitudinal optical phonon mode in pbse quantum dots
Physical Review B, 2013Co-Authors: J Habinshuti, O Kilian, O Cristinirobbe, A Sashchiuk, Ahmed Addad, S Turrell, Efrat Lifshitz, B Grandidier, Ludger WirtzAbstract:We have investigated the diameter dependence of the Raman spectra of lead selenide nanocrystals. The first-order Raman Peak at about 136 cm −1 and its second-order overtone at twice this wavenumber move up in energy with decreasing nanocrystal diameter. This anomalous behavior is interpreted in terms of quantum
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anomalous quantum confinement of the longitudinal optical phonon mode in pbse quantum dots
Physical Review B, 2013Co-Authors: J Habinshuti, O Kilian, O Cristinirobbe, A Sashchiuk, Ahmed Addad, S Turrell, Efrat Lifshitz, B Grandidier, Ludger WirtzAbstract:We have investigated the diameter dependence of the Raman spectra of lead selenide nanocrystals. The first-order Raman Peak at about 136 cm${}^{\ensuremath{-}1}$ and its second-order overtone at twice this wavenumber move up in energy with decreasing nanocrystal diameter. This anomalous behavior is interpreted in terms of quantum confinement of the longitudinal optical (LO) phonon whose frequency displays a minimum at \ensuremath{\Gamma} in the dispersion of bulk PbSe. We perform ab initio calculations of the phonons of PbSe slabs with up to 15 layers. The LO mode perpendicular to the slab shifts indeed upwards with decreasing layer thickness, thus validating the interpretation of the anomalous radius dependence of the Raman spectra in terms of quantum confinement.
O Kilian - One of the best experts on this subject based on the ideXlab platform.
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anomalous quantum confinement of the longitudinal optical phonon mode in pbse quantum dots
Physical Review B, 2013Co-Authors: J Habinshuti, O Kilian, O Cristinirobbe, A Sashchiuk, Ahmed Addad, S Turrell, Efrat Lifshitz, B Grandidier, Ludger WirtzAbstract:We have investigated the diameter dependence of the Raman spectra of lead selenide nanocrystals. The first-order Raman Peak at about 136 cm −1 and its second-order overtone at twice this wavenumber move up in energy with decreasing nanocrystal diameter. This anomalous behavior is interpreted in terms of quantum
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anomalous quantum confinement of the longitudinal optical phonon mode in pbse quantum dots
Physical Review B, 2013Co-Authors: J Habinshuti, O Kilian, O Cristinirobbe, A Sashchiuk, Ahmed Addad, S Turrell, Efrat Lifshitz, B Grandidier, Ludger WirtzAbstract:We have investigated the diameter dependence of the Raman spectra of lead selenide nanocrystals. The first-order Raman Peak at about 136 cm${}^{\ensuremath{-}1}$ and its second-order overtone at twice this wavenumber move up in energy with decreasing nanocrystal diameter. This anomalous behavior is interpreted in terms of quantum confinement of the longitudinal optical (LO) phonon whose frequency displays a minimum at \ensuremath{\Gamma} in the dispersion of bulk PbSe. We perform ab initio calculations of the phonons of PbSe slabs with up to 15 layers. The LO mode perpendicular to the slab shifts indeed upwards with decreasing layer thickness, thus validating the interpretation of the anomalous radius dependence of the Raman spectra in terms of quantum confinement.
J Habinshuti - One of the best experts on this subject based on the ideXlab platform.
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anomalous quantum confinement of the longitudinal optical phonon mode in pbse quantum dots
Physical Review B, 2013Co-Authors: J Habinshuti, O Kilian, O Cristinirobbe, A Sashchiuk, Ahmed Addad, S Turrell, Efrat Lifshitz, B Grandidier, Ludger WirtzAbstract:We have investigated the diameter dependence of the Raman spectra of lead selenide nanocrystals. The first-order Raman Peak at about 136 cm −1 and its second-order overtone at twice this wavenumber move up in energy with decreasing nanocrystal diameter. This anomalous behavior is interpreted in terms of quantum
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anomalous quantum confinement of the longitudinal optical phonon mode in pbse quantum dots
Physical Review B, 2013Co-Authors: J Habinshuti, O Kilian, O Cristinirobbe, A Sashchiuk, Ahmed Addad, S Turrell, Efrat Lifshitz, B Grandidier, Ludger WirtzAbstract:We have investigated the diameter dependence of the Raman spectra of lead selenide nanocrystals. The first-order Raman Peak at about 136 cm${}^{\ensuremath{-}1}$ and its second-order overtone at twice this wavenumber move up in energy with decreasing nanocrystal diameter. This anomalous behavior is interpreted in terms of quantum confinement of the longitudinal optical (LO) phonon whose frequency displays a minimum at \ensuremath{\Gamma} in the dispersion of bulk PbSe. We perform ab initio calculations of the phonons of PbSe slabs with up to 15 layers. The LO mode perpendicular to the slab shifts indeed upwards with decreasing layer thickness, thus validating the interpretation of the anomalous radius dependence of the Raman spectra in terms of quantum confinement.
