The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Christian Kränkel - One of the best experts on this subject based on the ideXlab platform.
-
rare earth doped Sesquioxides for diode pumped high power lasers in the 1 2 and 3 μm spectral range
IEEE Journal of Selected Topics in Quantum Electronics, 2015Co-Authors: Christian KränkelAbstract:Sesquioxides combine excellent thermomechanical properties, comparably low phonon energies and a strong crystal field, making them ideally suited for broad band emitting high power laser materials in the infrared and mid-infrared spectral range. In this paper, the latest progress on diode pumped highly efficient high-power solid-state lasers based on rare-earth doped Sesquioxides, Lu 2 O 3 , Sc 2 O 3 , and Y 2 O 3 , as well as different mixed Sesquioxides (Lu a Sc b Y c ) 2 O 3 with a + b + c = 1 is reviewed. While Yb 3+ -doped Sesquioxides allow for record high efficiencies at several 100 W of output power in continuous wave operation and record high average powers in pulsed mode in the 1-μm spectral range, Tm 3+ - and Ho 3+ -doped Sesquioxides enable efficient broad band laser operation and ultrashort pulse duration around 2 μm. Finally, Er 3+ -doped Sesquioxides enabled the highest efficiencies and output powers demonstrated so far at room temperature in the mid-infrared range at 3 μm.
-
Yb-doped mixed Sesquioxides for ultrashort pulse generation in the thin disk laser setup
Applied Physics B, 2013Co-Authors: Kolja Beil, Clara J. Saraceno, Cinia Schriber, Florian Emaury, Oliver H. Heckl, Cyrill R. E. Baer, Matthias Golling, Thomas Südmeyer, Ursula Keller, Christian KränkelAbstract:We report on spectroscopic investigations of the mixed sesquioxide laser materials Yb:LuScO_3, Yb:YScO_3, and Yb:(Lu,Y,Sc)_2O_3 as well as mode-locked thin disk laser experiments with Yb:LuScO_3 and Yb:(Lu,Y,Sc)_2O_3. The disordered crystal structures of these materials result in significantly broader emission spectra than for the pure Sesquioxides Yb:Sc_2O_3, Yb:Y_2O_3, and Yb:Lu_2O_3 providing a high potential for ultrashort pulse generation. In SESAM mode-locked thin disk laser experiments, pulse durations of around 100 fs could be obtained exploiting >70 % of the gain bandwidth which is to the best of our knowledge the optimum obtained so far for the mode-locked lasers in this setup.
-
Yb-doped mixed Sesquioxides for ultrashort pulse generation in the thin disk laser setup
Applied Physics B, 2013Co-Authors: Kolja Beil, Clara J. Saraceno, Cinia Schriber, Florian Emaury, Oliver H. Heckl, Cyrill R. E. Baer, Matthias Golling, Thomas Südmeyer, Ursula Keller, Christian KränkelAbstract:We report on spectroscopic investigations of the mixed sesquioxide laser materials Yb:LuScO_3, Yb:YScO_3, and Yb:(Lu,Y,Sc)_2O_3 as well as mode-locked thin disk laser experiments with Yb:LuScO_3 and Yb:(Lu,Y,Sc)_2O_3. The disordered crystal structures of these materials result in significantly broader emission spectra than for the pure Sesquioxides Yb:Sc_2O_3, Yb:Y_2O_3, and Yb:Lu_2O_3 providing a high potential for ultrashort pulse generation. In SESAM mode-locked thin disk laser experiments, pulse durations of around 100 fs could be obtained exploiting >70 % of the gain bandwidth which is to the best of our knowledge the optimum obtained so far for the mode-locked lasers in this setup.
-
ytterbium doped Sesquioxides for high power solid state lasers recent progress in crystal growth and laser operation
European Quantum Electronics Conference, 2009Co-Authors: Rigo Peters, K Petermann, Kolja Beil, Christian Kränkel, K Schenk, G. HuberAbstract:The cubic rare-earth doped Sesquioxides are known for their excellent thermal properties, high cross sections, and the possibility for high doping concentrations of the active ion. The combination of the low Stokes-shift of the ytterbium ion with the thin-disk laser geometry [1], which is one of the most sophisticated laser designs for power scaling [2], allows for an excellent beam quality and optical efficiency. Thus, up to laser output powers in the kW-range, Yb-doped Sesquioxides could even be superior to the standard thin-disk laser material Yb:YAG. Due to the relatively broad emission bands there is also a great potential for mode-locked laser operation of Yb-doped Sesquioxides [3–5]. However, the very high melting temperatures of about 2500°C hindered the production of crystalline material with a sufficient quality in the past [6].
Philippe Veber - One of the best experts on this subject based on the ideXlab platform.
-
Structural and Lattice-Dynamical Properties of Tb2O3 under Compression: A Comparative Study with Rare Earth and Related Sesquioxides
Inorganic Chemistry, 2020Co-Authors: Jordi Ibáñez, Matias Velázquez, Juan Ángel Sans, Vanesa Cuenca-gotor, Robert Oliva, Oscar Gomis, Placida Rodriguez-hernandez, Alfonso Munoz, Ulises Rodríguez-mendoza, Philippe VeberAbstract:We report a joint experimental and theoretical investigation of the high pressure structural and vibrational properties of terbium sesquioxide (Tb2O3). Powder X-ray diffraction and Raman scattering measurements show that cubic Ia3̅ (C-type) Tb2O3 undergoes two phase transitions up to 25 GPa. We observe a first irreversible reconstructive transition to the monoclinic C2/m (B-type) phase at ∼7 GPa and a subsequent reversible displacive transition from the monoclinic to the trigonal P3̅m1 (A-type) phase at ∼12 GPa. Thus, Tb2O3 is found to follow the well-known C → B → A phase transition sequence found in other cubic rare earth Sesquioxides with cations of larger atomic mass than Tb. Our ab initio theoretical calculations predict phase transition pressures and bulk moduli for the three phases in rather good agreement with experimental results. Moreover, Raman-active modes of the three phases have been monitored as a function of pressure, while lattice-dynamics calculations have allowed us to confirm the assignment of the experimental phonon modes in the C- and A-type phases as well as to make a tentative assignment of the symmetry of most vibrational modes in the B-type phase. Finally, we extract the bulk moduli and the Raman-active mode frequencies together with their pressure coefficients for the three phases of Tb2O3. These results are thoroughly compared and discussed in relation to those reported for rare earth and other related Sesquioxides as well as with new calculations for selected Sesquioxides. It is concluded that the evolution of the volume and bulk modulus of all the three phases of these technologically relevant compounds exhibit a nearly linear trend with respect to the third power of the ionic radii of the cations and that the values of the bulk moduli for the three phases depend on the filling of the f orbitals.
-
structural and lattice dynamical properties of tb2o3 under compression a comparative study with rare earth and related Sesquioxides
arXiv: Materials Science, 2020Co-Authors: Jordi Ibáñez, Matias Velázquez, Juan Ángel Sans, Robert Oliva, Oscar Gomis, Alfonso Munoz, V P Cuencagotor, P Rodriguezhernandez, U R Rodriguezmendoza, Philippe VeberAbstract:We report a joint experimental and theoretical investigation of the high-pressure structural and vibrational properties of terbium sesquioxide (Tb2O3). Powder x-ray diffraction and Raman scattering measurements show that cubic (C-type) Tb2O3 undergoes two phase transitions up to 25 GPa. We observe a first irreversible reconstructive transition to the monoclinic (B-type) phase at ~7 GPa and a subsequent reversible displacive transition from the monoclinic to the trigonal (A-type) phase at ~12 GPa. Thus, Tb2O3 is found to follow the well-known C-B-A phase transition found in other cubic rare-earth Sesquioxides with cations of larger atomic mass than Tb. Our ab initio theoretical calculations predict phase transition pressures and bulk moduli for the three phases in rather good agreement with experimental results. Moreover, Raman-active modes of the three phases have been monitored as a function of pressure and lattice-dynamics calculations have allowed us to confirm the assignment of the experimental phonon modes in the C-type phase as well as to make a tentative assignment of the symmetry of most vibrational modes in the B- and A-type phases. Finally, we extract the bulk moduli and the Raman-active modes frequencies together with their pressure coefficients for the three phases of Tb2O3. These results are thoroughly compared and discussed in relation to those reported for rare-earth and other related Sesquioxides. It is concluded that the evolution of the volume and bulk modulus of all the three phases of these technologically relevant compounds exhibit a nearly linear trend with respect to the third power of the ionic radii of the cations.
-
Laser demonstration with highly doped Yb:Gd2O3 and Yb:Y2O3 crystals grown by an original flux method.
Optics Letters, 2013Co-Authors: Frédéric Druon, Matias Velázquez, Philippe Veber, Sylvie Janicot, Oudomsack Viraphong, Gabriel Buse, Marwan Abdou Ahmed, Thomas Graf, Daniel Rytz, Patrick GeorgesAbstract: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.
Lu Chen - One of the best experts on this subject based on the ideXlab platform.
-
ab initio study on structure and phase transition of a and b type rare earth Sesquioxides ln2o3 ln la lu y and sc based on density function theory
Journal of Solid State Chemistry, 2007Co-Authors: Bo Wu, M Zinkevich, Fritz Aldinger, Lu ChenAbstract:Ab initio energetic calculations based on the density functional theory (DFT) and projector augmented wave (PAW) pseudo-potentials method were performanced to determine the crystal structural parameters and phase transition data of the polymorphic rare-earth Sesquioxides Ln2O3 (where Ln=La–Lu, Y, and Sc) with A-type (hexagonal) and B-type (monoclinic) configurations at ground state. The calculated results agree well with the limited experimental data and the critically assessed results. A set of systematic and self-consistent crystal structural parameters, energies and pressures of the phase transition were established for the whole series of the A- and B-type rare-earth Sesquioxides Ln2O3. With the increase of the atomic number, the ionic radii of rare-earth elements Ln and the volumes of the Sesquioxides Ln2O3 reflect the so-called “lanthanide contraction”. With the increase of the Ln3+-cation radius, the bulk modulus of Ln2O3 decreases and the polymorphic structures show a degenerative tendency.
Fritz Aldinger - One of the best experts on this subject based on the ideXlab platform.
-
ab initio study on structure and phase transition of a and b type rare earth Sesquioxides ln2o3 ln la lu y and sc based on density function theory
Journal of Solid State Chemistry, 2007Co-Authors: Bo Wu, M Zinkevich, Fritz Aldinger, Lu ChenAbstract:Ab initio energetic calculations based on the density functional theory (DFT) and projector augmented wave (PAW) pseudo-potentials method were performanced to determine the crystal structural parameters and phase transition data of the polymorphic rare-earth Sesquioxides Ln2O3 (where Ln=La–Lu, Y, and Sc) with A-type (hexagonal) and B-type (monoclinic) configurations at ground state. The calculated results agree well with the limited experimental data and the critically assessed results. A set of systematic and self-consistent crystal structural parameters, energies and pressures of the phase transition were established for the whole series of the A- and B-type rare-earth Sesquioxides Ln2O3. With the increase of the atomic number, the ionic radii of rare-earth elements Ln and the volumes of the Sesquioxides Ln2O3 reflect the so-called “lanthanide contraction”. With the increase of the Ln3+-cation radius, the bulk modulus of Ln2O3 decreases and the polymorphic structures show a degenerative tendency.
G. Huber - One of the best experts on this subject based on the ideXlab platform.
-
Growth of single and multilayer sesquioxide crystal films for lasing applications via pulsed laser deposition
2013Co-Authors: K.a. Sloyan, Robert W. Eason, S. Heinrich, G. HuberAbstract:Sesquioxides, materials of the form RE2O3 (RE: rare earth), are of great interest for lasing applications. These materials offer high thermal conductivities, are mechanically stable, can easily be doped with various rare earth ions and are optically isotropic. Members of the sesquioxide family have the same crystal structure but differing refractive indices, and hence are ideal candidates for multilayer as well as single film growth. Sesquioxides can be challenging to grow from the melt, however, due to their high melting points (>2400 °C)
-
Spectroscopy and laser operation of Nd-doped mixed Sesquioxides (Lu_1−x Sc_ x )_2O_3
Applied Physics B, 2012Co-Authors: Fabian Reichert, K Petermann, M Fechner, Philipp Koopmann, Christian Brandt, G. HuberAbstract:We report on crystal growth, spectroscopic investigations, crystal field tuning, and laser experiments of neodymium doped mixed Sesquioxides (Lu_1− x Sc_ x )_2O_3. Crystals were grown by the Nacken–Kyropoulos and the Heat-Exchanger method. Emission spectra for several mixing ratios are presented. Cw laser experiments were carried out with a 0.35 at.%-doped Nd:Lu_1.82Sc_0.18O_3 crystal by using a Ti:sapphire laser as pump source, achieving a maximum slope efficiency of 47 % with respect to the absorbed pump power and a maximum output power of 356 mW at a wavelength of 952.7 nm. To the best of our knowledge, this represents the first continous wave (cw) laser operation of a Nd-doped mixed sesquioxide.
-
Spectroscopy and laser operation of Nd-doped mixed Sesquioxides (Lu_1−x Sc_ x )_2O_3
Applied Physics B, 2012Co-Authors: Fabian Reichert, K Petermann, M Fechner, Philipp Koopmann, Christian Brandt, G. HuberAbstract:We report on crystal growth, spectroscopic investigations, crystal field tuning, and laser experiments of neodymium doped mixed Sesquioxides (Lu_1− x Sc_ x )_2O_3. Crystals were grown by the Nacken–Kyropoulos and the Heat-Exchanger method. Emission spectra for several mixing ratios are presented. Cw laser experiments were carried out with a 0.35 at.%-doped Nd:Lu_1.82Sc_0.18O_3 crystal by using a Ti:sapphire laser as pump source, achieving a maximum slope efficiency of 47 % with respect to the absorbed pump power and a maximum output power of 356 mW at a wavelength of 952.7 nm. To the best of our knowledge, this represents the first continous wave (cw) laser operation of a Nd-doped mixed sesquioxide.
-
spectroscopy and laser operation of nd doped mixed Sesquioxides lu 1 x sc x 2 o 3
Applied Physics B, 2012Co-Authors: Fabian Reichert, K Petermann, M Fechner, Philipp Koopmann, Christian Brandt, G. HuberAbstract:We report on crystal growth, spectroscopic investigations, crystal field tuning, and laser experiments of neodymium doped mixed Sesquioxides (Lu1−xScx)2O3. Crystals were grown by the Nacken–Kyropoulos and the Heat-Exchanger method. Emission spectra for several mixing ratios are presented. Cw laser experiments were carried out with a 0.35 at.%-doped Nd:Lu1.82Sc0.18O3 crystal by using a Ti:sapphire laser as pump source, achieving a maximum slope efficiency of 47 % with respect to the absorbed pump power and a maximum output power of 356 mW at a wavelength of 952.7 nm. To the best of our knowledge, this represents the first continous wave (cw) laser operation of a Nd-doped mixed sesquioxide.
-
ytterbium doped Sesquioxides for high power solid state lasers recent progress in crystal growth and laser operation
European Quantum Electronics Conference, 2009Co-Authors: Rigo Peters, K Petermann, Kolja Beil, Christian Kränkel, K Schenk, G. HuberAbstract:The cubic rare-earth doped Sesquioxides are known for their excellent thermal properties, high cross sections, and the possibility for high doping concentrations of the active ion. The combination of the low Stokes-shift of the ytterbium ion with the thin-disk laser geometry [1], which is one of the most sophisticated laser designs for power scaling [2], allows for an excellent beam quality and optical efficiency. Thus, up to laser output powers in the kW-range, Yb-doped Sesquioxides could even be superior to the standard thin-disk laser material Yb:YAG. Due to the relatively broad emission bands there is also a great potential for mode-locked laser operation of Yb-doped Sesquioxides [3–5]. However, the very high melting temperatures of about 2500°C hindered the production of crystalline material with a sufficient quality in the past [6].