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G. Huber

Bio: G. Huber is an academic researcher from University of Hamburg. The author has contributed to research in topics: Slope efficiency & Laser. The author has an hindex of 9, co-authored 14 publications receiving 559 citations.

Papers
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Journal ArticleDOI
L. Fornasiero1, E. Mix1, V. Peters1, Klaus Petermann1, G. Huber1 
TL;DR: In this paper, rare earth doped scandia and yttria have been grown from rhenium crucibles by the Czochralski technique, to the best of our knowledge.
Abstract: Rare earth doped scandia and yttria have been grown from rhenium crucibles by the Czochralski technique - to our knowledge for the first time. Spectroscopic data of Yb:Sc 2 O 3 are presented in detail and first laser experiments are reported. Despite the rather high crystal losses of about 2 % a slope efficiency of 37 % was obtained under diode pumping.

148 citations

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TL;DR: In this paper, the sesquioxides of scandium and lutetium are grown from the melt in rhenium crucibles suspended in a zirconia/gas insulation setup.

123 citations

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TL;DR: In this article, the authors quantitatively investigated the upconversion and quenching in neodymium-doped LaSc3(BO3)4 (LSB) and GdVO4 (GVO) laser crystals.
Abstract: Luminescence concentration quenching and upconversion have been quantitatively investigated in neodymium-doped LaSc3(BO3)4 (LSB) and GdVO4 (GVO) laser crystals. The microparameter of cross relaxation (self-quenching) was determined in Nd:GVO as 3.6×10-40 cm6/s. It is shown that, in Nd:LSB, upconversion is static, with the upconversion microparameter Cda=(0.5–1.1)×10-37 cm6/s. In Nd:GVO, upconversion is migration accelerated, with the upconversion macroparameter α≈1.2×10-15 cm3/s. The influence of upconversion on laser operation is discussed.

98 citations

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TL;DR: In this article, the intrinsic optical bistability in solid-state optical materials has been studied in the context of cooperative absorption and emission in Yb/sub 3/Al/Sub 3/O/sub 12.

48 citations

Journal ArticleDOI
TL;DR: In this paper, a rib channel waveguiding was demonstrated after structuring the films with reactive ion etching, and the results compared with a theoretical gain spectrum were compared with the results of a theoretical spectrum analysis.
Abstract: Monocrystalline lattice matched $Er(0.6$ $at.$ %):$(Gd,Lu)_2O_3$ films with nearly atomically flat surfaces and thicknesses up to 3 μm have been grown on $Y_2O_3$ substrates using pulsed laser deposition. The emission cross sections were comparable with the ones of $Er:Y_2O_3$ bulk crystals, showing only a marginal spectral broadening. Rib channel waveguiding could be demonstrated after structuring the films with reactive ion etching. Gain measurements have been performed and the results compared with a theoretical gain spectrum. A gain of 5.9 dB/cm could be measured at 1535.5 nm through in-band pumping at 1480 nm. The scattering losses in such a 7 mm long rib waveguide have been determined to be below 4.4 dB at 632.8 nm. An extrapolation to the gain wavelength with the $λ^{−4}$-Rayleigh law of scattering resulted in losses of 0.2 dB/cm at 1.5 μm.

45 citations


Cited by
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Journal ArticleDOI
TL;DR: Before the 1960s, all anti-Stokes emissions, which were known to exist, involved emission energies in excess of excitation energies by only a few kT and were linked to thermal population of energy states above excitation states by such an energy amount.
Abstract: Before the 1960s, all anti-Stokes emissions, which were known to exist, involved emission energies in excess of excitation energies by only a few kT. They were linked to thermal population of energy states above excitation states by such an energy amount. It was the well-known case of anti-Stokes emission for the so-called thermal bands or in the Raman effect for the well-known anti-Stokes sidebands. Thermoluminescence, where traps are emptied by excitation energies of the order of kT, also constituted a field of anti-Stokes emission of its own. Superexcitation, i.e., raising an already excited electron to an even higher level by excited-state absorption (ESA), was also known but with very weak emissions. These types of well-known anti-Stokes processes have been reviewed in classical textbooks on luminescence.1 All fluorescence light emitters usually follow the well-known principle of the Stokes law which simply states that excitation photons are at a higher energy than emitted ones or, in other words, that output photon energy is weaker than input photon energy. This, in a sense, is an indirect statement that efficiency cannot be larger than 1. This principle is

4,279 citations

Journal ArticleDOI
TL;DR: This critical review describes the latest developments in the sensitization of near-infrared luminescence, "soft" luminescent materials (liquid crystals, ionic liquids, ionogels), electroluminescentmaterials for organic light emitting diodes, with emphasis on white light generation, and applications in luminecent bio-sensing and bio-imaging based on time-resolved detection and multiphoton excitation.
Abstract: Recent startling interest for lanthanide luminescence is stimulated by the continuously expanding need for luminescent materials meeting the stringent requirements of telecommunication, lighting, electroluminescent devices, (bio-)analytical sensors and bio-imaging set-ups. This critical review describes the latest developments in (i) the sensitization of near-infrared luminescence, (ii) “soft” luminescent materials (liquid crystals, ionic liquids, ionogels), (iii) electroluminescent materials for organic light emitting diodes, with emphasis on white light generation, and (iv) applications in luminescent bio-sensing and bio-imaging based on time-resolved detection and multiphoton excitation (500 references).

2,895 citations

Journal ArticleDOI
TL;DR: The literature on 4f n ↔4f n −1 5d transitions of the trivalent lanthanides in inorganic compounds has been collected as mentioned in this paper from critically analyzing fd-excitation, absorption, reflection and df-emission spectra, values for the spectroscopic red shift of 5d levels and the stokes shift were determined.

853 citations

Journal ArticleDOI
TL;DR: Transparent polycrystalline ceramics have found various applications, such as laser hosts, infrared windows/domes, lamp envelopes and transparent armors, due mainly to their processing flexibility in fabricating items with large sizes and complex shapes and more importantly costeffectiveness as mentioned in this paper.

453 citations

Journal ArticleDOI
L. G. Van Uitert1
TL;DR: In this article, the position of the d-band edge (E) in energy for rare earth ions that fluoresce with broad emission bands is known to be sensitive to electron-electron repulsion between the active cation and its surrounding anions.

352 citations