Spectroscopic and stimulated emission Characteristics of Nd/sup 3+/ in transparent YAG ceramics

Kumar, Gaurav; Lu, Jianren; Kaminskiĭ, A. A.; Ueda, Ken–ichi; Yagi, Hideki; Yanagitani, Takahiko; Unnikrishnan, N.V.

doi:10.1109/jqe.2004.828263

Cited by 106 publications

(67 citation statements)

References 25 publications

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“…Our measurements are in sharp contrast with the data obtained on fine-grained Nd: YAG ceramics produced by wet-chemistry synthesis [7], where large differences (even one order of magnitude) from those measured on single crystals are reported for some crosssections. For Nd…”

Section: The Absorption and Emission Cross-sections For The Isolated contrasting

confidence: 99%

High resolution spectroscopic properties and emission decay of rare‐earth doped transparent laser ceramics

Lupeǐ

Ikesue³

2007

Phys. Status Solidi (c)

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The paper discusses the use of high-resolution spectroscopy and emission decay for investigation of the variety, nature, structure and distribution of the centers formed by the rare earth ions in transparent polycrystalline ceramics of cubic oxide laser materials (garnets and sesquioxides). It is shown that for ceramics with grains of the order of tens of microns the spectroscopic and population dynamics properties of the doping ions can be described consistently based on the crystal structure of the host material and assuming random distribution even at concentrations much larger than that available for the single crystals. It is inferred that from spectroscopic point of view these ceramics can substitute the crystals as laser materials and their enhanced compositional versatility enables tailoring of new laser materials.1 Introduction Transparent ceramics activated with laser active rare earth (RE) ions are currently investigated as possible substitutes for the single crystal laser materials. These ceramics consist of tightly-packed, randomly oriented crystalline grains and can be useful in case of cubic laser materials such as the garnets or the cubic sesquioxides Ln 2 O 3 (Ln = Y, Lu, Sc). The high melting temperatures (1900-2000 °C for garnets and over 2400 °C for sesquioxides) makes the crystal growth difficult and costly; moreover, the size of the crystals is limited, while in many cases the segregation coefficient and the maximum doping concentration are quite low [1]. The fabrication of the transparent ceramics can be grouped in two basic techniques according to the synthesis method of the compound: solid-state synthesis [2] and wet-chemistry [3]. The grain sizes are determined by the thermal regime (temperature, duration) of the final sintering stage: high transparency is obtained for crystallites of several µm to a few tens of µm. Besides obvious technological advantages and lover cost, the transparent ceramics offer major functional advantages, such as enhanced compositional versatility, higher doping concentrations and the possibility to control the homogeneity of doping. Nevertheless, important problems, such as the variety, structure and spectroscopic properties (energy levels, transition probabilities) of the structural centers of the doping ions, the distribution of the RE 3+ at the available sites and in the ceramic grains as well as the effects of granular structure on the ion-ion or electron-phonon interactions remain of concern and the data from literature are still contradictory. This paper discusses the use of high resolution spectroscopy and emission decay for solving these problems in case of RE 3+ -doped garnet (YAG) or cubic sesquioxide (Y 2 O 3 , Sc 2 O 3 ) transparent ceramics produced by the method of solid-state synthesis.

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Section: The Absorption and Emission Cross-sections For The Isolated contrasting

confidence: 99%

High resolution spectroscopic properties and emission decay of rare‐earth doped transparent laser ceramics

Lupeǐ

Ikesue³

2007

Phys. Status Solidi (c)

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“…Thus, in case of the 1 at.% Nd-doped YAG ceramics the relative intensities of the absorption and emission lines and their peak cross-sections are quite similar to those measured for Czochralski single crystals, for instance the effective peak absorption cross-section at 300 K of the line 4 I 9/2 (Z 1 ) → 4 F 3/2 (R 1 ) at 875.3 nm equals 0.67 × 10 −20 cm 2 , while that of the line 4 I 9/2 (Z 1 ) → 4 F 3/2 (R 2 ) at 868.9 nm is 2.7 × 10 −20 cm 2 These data are in sharp contrast to those measured for fine-grained 1 at.% Nd:YAG ceramics produced by wet-chemistry synthesis [7], 0.66 × 10 −20 cm 2 and respectively 1.67 × 10 −20 cm 2 . Similar discrepancies are reported in case of the emission properties, for instance the effective room temperature emission crosssection at 1064.15 nm in our case was 3 × 10 −19 cm 2 for the 1 at.% Nd:YAG ceramic and 2.95 × 10 −19 cm 2 for the single crystal, while Ref.…”

Section: The Absorption and Emission Cross-sections Of The Doping Cencontrasting

confidence: 57%

Comparative spectroscopic investigation of rare earth-doped oxide transparent ceramics and single crystals

Lupeǐ

2008

Journal of Alloys and Compounds

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“…The multiphonon relaxation probability depends, mainly, on the energy gap between the 4 F 3/2 and 4 I 15/2 states of Nd 3+ ions and on the energy of the effective phonon involved in the de-excitation process. 40 According to previous works, 45,46 these two parameters are not expected to vary from YAG crystals to YAG ceramics. Therefore, the temperature dependences of the 4 F 3/2 fluorescence lifetimes seem to indicate that Nd:YAG ceramics have not a higher density of lattice defects with respect to Nd:YAG crystals.…”

Section: B Comparative Luminescence Investigationsmentioning

confidence: 94%

Microstructuration induced differences in the thermo-optical and luminescence properties of Nd:YAG fine grain ceramics and crystals

Jacinto

Benayas

Catunda

et al. 2008

The Journal of Chemical Physics

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Third-order nonlinear optical response and photoluminescence characterization of tellurite glasses with different alkali metal oxides as network modifiers J. Appl. Phys. 110, 083110 (2011) In-plane thermal conductivity determination through thermoreflectance analysis and measurements J. Appl. Phys. 110, 084313 (2011) Tuning of a cavity in a silicon photonic crystal by thermal expansion of an elastomeric infill Appl. Phys. Lett. 99, 111113 (2011) Assessing the thermal conductivity of non-uniform thin-films: Nanocrystalline Cu composites incorporating carbon nanotubes J. Appl. Phys. 110, 023506 (2011) Strong absorption and selective thermal emission from a midinfrared metamaterial Appl. Phys. Lett. 98, 241105 (2011) Additional information on J. Chem. Phys. The temperature and compositional dependences of thermo-optical properties of neodymium doped yttrium aluminum garnet ͑YAG͒ crystals and fine grain ceramics have been systematically investigated by means of time-resolved thermal lens spectrometry. We have found that Nd:YAG ceramics show a reduced thermal diffusivity compared to Nd:YAG single crystals in the complete temperature range investigated ͑80-300 K͒. The analysis of the time-resolved luminescent properties of Nd 3+ has revealed that the reduction in the phonon mean free path taking place in Nd:YAG ceramics cannot be associated with an increment in the density of lattice defects, indicating that phonon scattering at grain boundaries is the origin of the observed reduction in the thermal diffusivity of Nd:YAG ceramics. Finally, our results showed the ability of the time-resolved thermal lens to determine and optimize the thermo-optical properties of Nd:YAG ceramic based lasers.

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Spectroscopic and stimulated emission Characteristics of Nd/sup 3+/ in transparent YAG ceramics

Cited by 106 publications

References 25 publications

High resolution spectroscopic properties and emission decay of rare‐earth doped transparent laser ceramics

High resolution spectroscopic properties and emission decay of rare‐earth doped transparent laser ceramics

Comparative spectroscopic investigation of rare earth-doped oxide transparent ceramics and single crystals

Microstructuration induced differences in the thermo-optical and luminescence properties of Nd:YAG fine grain ceramics and crystals

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