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G Huber - One of the best experts on this subject based on the ideXlab platform.

  • 1W continuous-wave laser generation and Excited State Absorption measurements inCr2+:ZnSe
    Advanced Solid State Lasers, 2000
    Co-Authors: A.v. Podlipensky, Stefan Kuck, V. G. Shcherbitsky, N. V. Kuleshov, V. I. Levchenko, V.n. Yakimovich, A. Diening, Michael Mond, G Huber
    Abstract:

    Excited State Absorption spectra were measured for Cr2+:ZnSe in the spectral range between 1.2 and 3 µm at room temperature. Stimulated emission band was observed from 2 to 3 µm with peak cross section of 8×10−19 cm2 at 2400 nm. Excited State Absorption was shown to be negligible in the pump and laser range. Efficient continuous wave laser operation of Cr2+:ZnSe laser was demonstrated with output power as high as 1W at 1670 mW of absorbed power.

  • Near Infrared and Visible Excited-State Absorption in Cr4+:Forsterite
    Advanced Solid State Lasers, 1997
    Co-Authors: N. V. Kuleshov, Stefan Kuck, V. G. Shcherbitsky, Klaus Petermann, V. P. Mikhailov, S. Hartung, G Huber
    Abstract:

    Polarization-dependent Excited-State Absorption observed in Cr4+:forsterite in the infrared and visible spectral range at 295 K and 10 K is assigned to transitions between emitting level and the orbital components of the 3T1a and 3T1b States of the four-fold coordinated Cr4+ ion. Excited-State Absorption and stimulated emission cross sections are estimated.

  • Excited-State Absorption and stimulated emission measurements in Cr4+:forsterite
    Journal of Luminescence, 1997
    Co-Authors: N. V. Kuleshov, Stefan Kuck, V. G. Shcherbitsky, Klaus Petermann, V. P. Mikhailov, S. Hartung, T. Danger, G Huber
    Abstract:

    Abstract Polarized cw and time-resolved Excited-State Absorption spectra were measured in Cr 4+ -doped Mg 2 SiO 4 in the 200–2200 nm spectral region. Polarization-dependent Excited-State Absorption was observed in the infrared due to the 3 T 2 → 3 T 1a transitions extending from 1100 to 2100 nm, in the visible between 600 and 800 nm (E∥a) due to the 3 T 2 → 3 T 1b transition, as well as in the UV range from 200 to 450 nm, likely due to the charge transfer transitions. Stimulated emission between 1100 and 1500 nm was observed in Cr 4+ :Mg 2 SiO 4 for E∥b polarization.

  • Excited State Absorption and its influence on the laser behavior of Cr4+-doped garnets
    Journal of Luminescence, 1997
    Co-Authors: Stefan Kuck, Klaus Petermann, S. Hartung, Kenneth L. Schepler, G Huber
    Abstract:

    Abstract Polarization-dependent Excited State Absorption measurements of Cr 4+ :Y 3 Al 5 O 12 , Cr 4+ :Y 3 Sc 0.9 Al 4.1 O 12 , and Cr 4+ :Y 3 Sc 2 Ga 3 O 12 are presented and analyzed. Different polarization dependencies and Excited State Absorption spectra are observed. While Cr 4+ :Y 3 Al 5 O 12 exhibits a strong polarization dependence, it is less pronounced in Cr 4+ :Y 3 Sc 0.9 Al 4.1 O 12 and strongly diminished for Cr 4+ :Y 3 Sc 2 Ga 3 O 12 . We believe that the poor efficiency or even the absence of laser oscillation in a variety of Cr 4+ -doped garnets is caused by this different polarization and Excited State Absorption behavior.

  • Excited State Absorption and stimulated emission measurements of Cr4+-doped Y3Al5O12, Y3Sc0.9Al 4.1O12, and CaY2Mg2Ge3O12
    Advanced Solid State Lasers, 1996
    Co-Authors: S. Kück, K. L. Schepler, K. Petermann, G Huber
    Abstract:

    Excited State Absorption measurements of different garnet crystals are presented and analyzed. The Excited State Absorption in Cr4+-doped garnets is strongly polarization dependent as a result of the garnet lattice structure and the selection rules for electronic transitions. Stimulated emission is observed between 1300nm and 1750nm for Cr4+:Y3Al5O12 and between 1300nm and 1950nm for Cr4+:Y3Sc0.9Al4.1O12. No Excited State Absorption is observed in the long wavelength part of the emission. First spectroscopic results of Cr4+:CaY2Mg2Ge3O12 are also presented.

Cleber Renato Mendonça - One of the best experts on this subject based on the ideXlab platform.

  • Excited State Absorption of doped and undoped polyanyline
    Molecular Crystals and Liquid Crystals, 2010
    Co-Authors: Daniel S. Correa, L. De Boni, Débora Terezia Balogh, Cleber Renato Mendonça
    Abstract:

    Polyaniline is a conducting polymer with appealing electrical and optical properties, arising from the π-conjugation along the polymer backbone. The understanding of its Excited State Absorption is of prime importance for designing and fabricating optical devices. Here, we report on the study of the Excited State Absorption of doped and undoped PANI by using femtosecond pulses in the spectral range from 450 nm up to 850 nm. For undoped PANI, we observed saturation of Absorption as well as reverse saturable Absorption, depending on the excitation wavelength. For doped PANI, however, only saturable Absorption was observed.

  • Excited State Absorption Study in Sulfonated-Halogenated Porphyrins
    Latin America Optics and Photonics Conference, 2010
    Co-Authors: L. De Boni, Pablo José Gonçalves, C.j.p. Monteiro, M. M. Pereira, S. C. Zilio, Cleber Renato Mendonça
    Abstract:

    Excited State Absorption of sulfonated-halogenated porphyrins was characterized using the Z-scan technique. We obtained similar values of the Excited State Absorption cross-section if compared with ground State ones, which have demonstrated an efficient Absorption.

  • Excited-State Absorption spectroscopy in oxidized Cytochrome c
    Optical Materials, 2010
    Co-Authors: L. De Boni, S. C. Zilio, A.a. Andrade, Lino Misoguti, Cleber Renato Mendonça
    Abstract:

    Abstract This work reports on the Excited-State Absorption spectrum of oxidized Cytochrome c (Fe 3+ ) dissolved in water, measured with the Z-scan technique with femtosecond laser pulses. The Excited-State Absorption cross-sections between 460 and 560 nm were determined with the aid of a three-energy-level model. Reverse saturable Absorption was observed below 520 nm, while a saturable Absorption process occurs in the Q-band, located around 530 nm. Above 560 nm, a competition between saturable Absorption and two-photon Absorption was inferred. These results show that Cytochrome c presents distinct nonlinear behaviors, which may be useful to study electron transfer chemistry in proteins by one- and two-photon Absorption. In addition, owing to these nonlinear optical features, this molecule may be employed in applications involving photodynamics therapy and saturable absorbers.

  • Excited State Absorption in conjugated polymers: Photoinduced transparency
    Polymer, 2007
    Co-Authors: Daniel S. Correa, L. De Boni, Vanessa C. Gonçalves, Débora T. Balogh, Cleber Renato Mendonça
    Abstract:

    Abstract The understanding of Excited States of conjugated polymers is of great interest for photonics, especially for fabricating electroluminescent and optical devices. This work concerns the Excited State Absorption of three conjugated polymers: poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), poly[2-[ethyl-[4-(4-nitro-phenylazo)-phenyl]-amino]-ethane-(3-thienyl)-ethanoate] (PAzT), and poly(3-octyl-thiophene) (POT). The nonlinear spectra from 450 nm up to 700 nm for the three polymers were obtained by means of the white-light continuum Z-scan technique. Saturation of Absorption was observed due to the ground State depletion for the three polymers. In addition to this effect, we also observed a small Excited State Absorption for POT. The Absorption from the first to a higher Excited State is negligible for MEH-PPV and PAzT. In contrast, POT presented Absorption for a higher Excited State, which allowed the determination of its Excited State Absorption cross-section.

Stefan Kuck - One of the best experts on this subject based on the ideXlab platform.

  • 1W continuous-wave laser generation and Excited State Absorption measurements inCr2+:ZnSe
    Advanced Solid State Lasers, 2000
    Co-Authors: A.v. Podlipensky, Stefan Kuck, V. G. Shcherbitsky, N. V. Kuleshov, V. I. Levchenko, V.n. Yakimovich, A. Diening, Michael Mond, G Huber
    Abstract:

    Excited State Absorption spectra were measured for Cr2+:ZnSe in the spectral range between 1.2 and 3 µm at room temperature. Stimulated emission band was observed from 2 to 3 µm with peak cross section of 8×10−19 cm2 at 2400 nm. Excited State Absorption was shown to be negligible in the pump and laser range. Efficient continuous wave laser operation of Cr2+:ZnSe laser was demonstrated with output power as high as 1W at 1670 mW of absorbed power.

  • Near Infrared and Visible Excited-State Absorption in Cr4+:Forsterite
    Advanced Solid State Lasers, 1997
    Co-Authors: N. V. Kuleshov, Stefan Kuck, V. G. Shcherbitsky, Klaus Petermann, V. P. Mikhailov, S. Hartung, G Huber
    Abstract:

    Polarization-dependent Excited-State Absorption observed in Cr4+:forsterite in the infrared and visible spectral range at 295 K and 10 K is assigned to transitions between emitting level and the orbital components of the 3T1a and 3T1b States of the four-fold coordinated Cr4+ ion. Excited-State Absorption and stimulated emission cross sections are estimated.

  • Spectroscopy and Excited-State Absorption of Ni2+-doped MgAl2O4
    Journal of Luminescence, 1997
    Co-Authors: N. V. Kuleshov, Stefan Kuck, V. G. Shcherbitsky, J. Koetke, Klaus Petermann, V. P. Mikhailov, Guenter Huber
    Abstract:

    Abstract Luminescence, ground-State and Excited-State Absorption and lifetime measurements on Ni2+-doped MgAl2O4 were performed. Excited-State Absorption bands at 1700 nm in the near infrared and at 750 and 580 nm in the visible region due to the transitions from the 3T2 (3F) metastable State to the 3T1(3F), 1T2(1D), and 3T1(3P) States were observed and ESA cross sections were determined. The 3T2-3T1(3F) ESA band overlaps with the emission band and prevents lasing of Ni2+ : MgAl2O4 at room temperature.

  • Excited-State Absorption and stimulated emission measurements in Cr4+:forsterite
    Journal of Luminescence, 1997
    Co-Authors: N. V. Kuleshov, Stefan Kuck, V. G. Shcherbitsky, Klaus Petermann, V. P. Mikhailov, S. Hartung, T. Danger, G Huber
    Abstract:

    Abstract Polarized cw and time-resolved Excited-State Absorption spectra were measured in Cr 4+ -doped Mg 2 SiO 4 in the 200–2200 nm spectral region. Polarization-dependent Excited-State Absorption was observed in the infrared due to the 3 T 2 → 3 T 1a transitions extending from 1100 to 2100 nm, in the visible between 600 and 800 nm (E∥a) due to the 3 T 2 → 3 T 1b transition, as well as in the UV range from 200 to 450 nm, likely due to the charge transfer transitions. Stimulated emission between 1100 and 1500 nm was observed in Cr 4+ :Mg 2 SiO 4 for E∥b polarization.

  • Excited State Absorption and its influence on the laser behavior of Cr4+-doped garnets
    Journal of Luminescence, 1997
    Co-Authors: Stefan Kuck, Klaus Petermann, S. Hartung, Kenneth L. Schepler, G Huber
    Abstract:

    Abstract Polarization-dependent Excited State Absorption measurements of Cr 4+ :Y 3 Al 5 O 12 , Cr 4+ :Y 3 Sc 0.9 Al 4.1 O 12 , and Cr 4+ :Y 3 Sc 2 Ga 3 O 12 are presented and analyzed. Different polarization dependencies and Excited State Absorption spectra are observed. While Cr 4+ :Y 3 Al 5 O 12 exhibits a strong polarization dependence, it is less pronounced in Cr 4+ :Y 3 Sc 0.9 Al 4.1 O 12 and strongly diminished for Cr 4+ :Y 3 Sc 2 Ga 3 O 12 . We believe that the poor efficiency or even the absence of laser oscillation in a variety of Cr 4+ -doped garnets is caused by this different polarization and Excited State Absorption behavior.

Richard Moncorgé - One of the best experts on this subject based on the ideXlab platform.

  • Excited-State Absorption and fluorescence dynamics of Er3+:KY3F10
    Optical Materials, 2018
    Co-Authors: Christophe Labbé, Richard Moncorgé, Jean-louis Doualan, Alain Braud, Patrice Camy
    Abstract:

    Abstract We report here on a complete investigation of the Excited-State Absorption and fluorescence dynamics of Er3+ doped KY3F10 single crystals versus dopant concentrations and optical excitation conditions. Radiative and effective (including non-radiative relaxations) emission lifetimes and branching ratios are determined from a Judd-Ofelt analysis of the Absorption spectra and via specific fluorescence experiments using wavelength selective laser excitations. Excited-State Absorption and emission spectra are registered within seven spectral domains, i.e. 560 nm, 650 nm, 710 nm, 810 nm, 970 nm, 1550 nm and 2750 nm. A maximum gain cross-section of 0.93 × 10−21 cm2 is determined at the potential laser wavelength of 2.801 μm for a population ratio of 0.48. Saturation of fluorescence intensities and variations of population ratios versus pumping rates are registered and confronted with a rate equation model to derive the rates of the most important up-conversion and cross-relaxation energy transfers occurring at high dopant concentrations.

  • Ground- and Excited-State Absorption and emission spectroscopy of Nd:GGG
    Journal of Luminescence, 2012
    Co-Authors: Rémi Soulard, Patrice Camy, Jean-louis Doualan, Richard Moncorgé
    Abstract:

    Abstract Complete room temperature Absorption, Excited-State Absorption and emission spectra of Nd:GGG have been registered and calibrated in cross section units in the near infrared around the main pump and laser emission transitions of Nd:GGG.

  • Excited-State Absorption of Er3+-doped LiNbO3
    Journal of Applied Physics, 1999
    Co-Authors: R. Burlot-loison, Richard Moncorgé, Jean-louis Doualan, P. Le Boulanger, T. P. J. Han, H. G. Gallagher, Georges Boulon
    Abstract:

    The Excited State Absorption spectra of an Er:LiNbO3 single crystal are reported and analyzed versus polarization in both visible and near infrared spectral regions between 500 and 1800 nm. These spectra are completed with Excited State excitation (ESE) spectra of the bright green anti-Stokes fluorescence observed in this material. These ESE spectra are recorded more particularly around 800 and 980 nm, and the results are analyzed in view of up-conversion laser operation after diode laser pumping around these two wavelengths.

  • Excited State Absorption of erbium-doped laser crystals
    Journal of Luminescence, 1997
    Co-Authors: Jean-louis Doualan, P. Le Boulanger, Sylvain Girard, J. Margerie, F.-s. Ermeneux, Richard Moncorgé
    Abstract:

    The Excited State Absorption of the 4I132 level has been measured in Er3+-doped YVO4 and phosphate glass from 400 to 1900 nm. We use a cw pump probe technique. In Er:YVO4 the ESA starts at 1650 nm. In Er:phosphate glass the ESA appears at 1565 nm and will consequently reduce or prevent the great wavelength laser emission.

  • Saturable and Excited State Absorption measurements in Cr4+:LuAG single crystals
    Optics Communications, 1996
    Co-Authors: Richard Moncorgé, H. Manaa, F. Deghoul, Yannick Guyot, Yehoshua Kalisky, S. A. Pollack, E. V. Zharikov, Milan R. Kokta
    Abstract:

    Abstract The performance of a Q-switched Nd-YAG laser using Cr4+:Lu3Al5O12 (LuAG) as a passive shutter is demonstrated with 35% conversion efficiency between the free-running and the Q-switched mode. From the transmission saturation curves, the ground State and the Excited State Absorption cross-sections were evaluated. Furthermore, the Excited State Absorption spectrum of Cr4+:LuAG in its Absorption and emission domains was obtained and characterized. Pulsed laser emission of Cr4+:LuAG pumped at 1.064 μm was also obtained, though for a short period of time.

L. De Boni - One of the best experts on this subject based on the ideXlab platform.

  • Excited State Absorption of doped and undoped polyanyline
    Molecular Crystals and Liquid Crystals, 2010
    Co-Authors: Daniel S. Correa, L. De Boni, Débora Terezia Balogh, Cleber Renato Mendonça
    Abstract:

    Polyaniline is a conducting polymer with appealing electrical and optical properties, arising from the π-conjugation along the polymer backbone. The understanding of its Excited State Absorption is of prime importance for designing and fabricating optical devices. Here, we report on the study of the Excited State Absorption of doped and undoped PANI by using femtosecond pulses in the spectral range from 450 nm up to 850 nm. For undoped PANI, we observed saturation of Absorption as well as reverse saturable Absorption, depending on the excitation wavelength. For doped PANI, however, only saturable Absorption was observed.

  • Excited State Absorption Study in Sulfonated-Halogenated Porphyrins
    Latin America Optics and Photonics Conference, 2010
    Co-Authors: L. De Boni, Pablo José Gonçalves, C.j.p. Monteiro, M. M. Pereira, S. C. Zilio, Cleber Renato Mendonça
    Abstract:

    Excited State Absorption of sulfonated-halogenated porphyrins was characterized using the Z-scan technique. We obtained similar values of the Excited State Absorption cross-section if compared with ground State ones, which have demonstrated an efficient Absorption.

  • Excited State Absorption study in hematoporphyrin IX.
    Journal of fluorescence, 2009
    Co-Authors: L. De Boni, Carlos Toro, Florencio E. Hernandez
    Abstract:

    We present the study of the Excited State Absorption of Hematoporphyrin IX dissolved in dimethyl sulfoxide. All measurements were carried out using open aperture Z-scan and white-light continuum pump-probe with picosecond pulses to avoid triplet Excited State Absorption. Without the latter contribution, the results obtained with both techniques show a transition to a high singlet Excited State. The vibronic progression of the Q-band is observed due to photobleaching of the ground State. In addition, we show that the Excited State presents reverse saturable Absorption for most of the spectral range studied. A long relaxation component of the first singlet Excited State was evidenced with the pump-probe experiment. This result is in agreement with fluorescence lifetime and fluorescence quantum yield measurements. In order to elucidate the origin of the nonlinear effects, we used a three-level energy diagram to describe the principal singlet-singlet transitions.

  • Excited State Absorption in conjugated polymers: Photoinduced transparency
    Polymer, 2007
    Co-Authors: Daniel S. Correa, L. De Boni, Vanessa C. Gonçalves, Débora T. Balogh, Cleber Renato Mendonça
    Abstract:

    Abstract The understanding of Excited States of conjugated polymers is of great interest for photonics, especially for fabricating electroluminescent and optical devices. This work concerns the Excited State Absorption of three conjugated polymers: poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), poly[2-[ethyl-[4-(4-nitro-phenylazo)-phenyl]-amino]-ethane-(3-thienyl)-ethanoate] (PAzT), and poly(3-octyl-thiophene) (POT). The nonlinear spectra from 450 nm up to 700 nm for the three polymers were obtained by means of the white-light continuum Z-scan technique. Saturation of Absorption was observed due to the ground State depletion for the three polymers. In addition to this effect, we also observed a small Excited State Absorption for POT. The Absorption from the first to a higher Excited State is negligible for MEH-PPV and PAzT. In contrast, POT presented Absorption for a higher Excited State, which allowed the determination of its Excited State Absorption cross-section.