Home  About us  Contact
 

Emission Cross Section (emission + cross_section)

Distribution by Scientific Domains
Physics and Astronomy80%

Selected Abstracts

Fabrication and Luminescent Properties of Nd3+ -Doped Lu2O3 Transparent Ceramics by Pressureless Sintering

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2009
Ding Zhou
The fabrication of transparent Nd3+ ion-doped Lu2O3 ceramics is investigated by pressureless sintering under a flowing H2 atmosphere. The starting Nd-doped Lu2O3 nanocrystalline powder is synthesized by a modified coprecipitant processing using a NH4OH+NH4HCO3 mixed solution as the precipitant. The thermal decomposition behavior of the precipitate precursor is studied by thermogravimetric analysis and differential thermal analysis. After calcination at 1000°C for 2 h, monodispersed Nd3+:Lu2O3 powder is obtained with a primary particle size of about 40 nm and a specific surface area of 13.7 m2/g. Green compacts, free of additives, are formed from the as-synthesized powder by dry pressing followed by cold isostatic pressing. Highly transparent Nd3+:Lu2O3 ceramics are obtained after being sintered under a dry H2 atmosphere at 1880°C for 8 h. The linear optical transmittance of the polished transparent samples with a 1.4 mm thickness reaches 75.5% at the wavelength of 1080 nm. High-resolution transmission electron microscopy observations demonstrate a "clear" grain boundary between adjacent grains. The luminescent spectra showed that the absorption coefficient of the 3 at.% Nd-doped Lu2O3 ceramic at 807 nm reached 14 cm,1, while the emission cross section at 1079 nm was 6.5 × 10,20 cm2. [source]

Set temperature dependence of fractional thermal loading and effective stimulated emission cross section of a diode double end pumped TEM00 Nd:YAG laser for micromachining application

LASER PHYSICS LETTERS, Issue 5 2006
S. K. Sudheer
Abstract We discuss the set temperature dependence of fractional thermal loading and effective stimulated emission cross section of an efficient, diode double end -pumped Nd:YAG laser using two 30 W pump diodes with a CW output power greater than 8 W in polarized TEM00 mode near-diffraction limited beam suitable for micromachining applications of ultra hard materials like diamond. The temperature dependence of effective stimulated emission cross section for 4F3/2 , 4I11/2 transition and fractional thermal loading of Nd:YAG are determined where the pump power induced thermal lensing is used to make the cavity stable and in thermally stabilized solid state lasers the cavity parameters change dynamically with the pump power and hence the overlap integrals become a function of absorbed pump power. It is observed that the fractional thermal loading is increasing with increase in set temperature of laser crystal and effective stimulated emission cross section is increasing almost linearly with the increase in set temperature of laser crystal and pump laser diodes up to 30 °C the rated value of the pump diodes and thereafter the cross section decreases with increase in temperature. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Spectroscopic properties of La3Ga5SiO14:Er3+ (1%) crystals

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 11 2006
Zeng M. Wang
Abstract Single crystals of Erbium (Er) doped La3Ga5SiO14 (LGS) have been grown along c-axis by using the Czochralski method. The absorption and fluorescence spectra of LGS: Er3+ single crystals have been measured and analyzed according to the Judd-Ofelt theory. When applied, the following spectral parameters have been obtained: intensity parameters ,t, ,2= 2.741674×10 -20cm2, ,4= 0.66934×10 -20 cm2 and ,6= 0.592591×10 -20 cm2, radiative transition probabilities AJ,J", PJ,J". The radiative lifetime of levels 4I13/2, 4H9/2, 4S3/2 are 11.333ms, 0.447ms and 0.704ms, respectively. The fluorescence branching ratios and the integrated emission cross sections are also calculated. The results suggest that LGS: Er crystals have potential applications as a laser material. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Ultraviolet and visible emission cross-sections for Tm3+ : YLiF4 laser system

LASER PHYSICS LETTERS, Issue 2 2004
T.D. Medoidze
Abstract We present the measured values of emission cross sections for 1I6 manifold of Tm3+ embedded in YLiF4. For these measurements the original experimental equipment for laserexited fluorescence spectroscopy is used. The outcomes have potential applications to ultraviolet and visible, including tunable lasing based on 4f , 4f intra-configurational transitions in Tm3+ : YLiF4 systems. (© 2004 by HMS Consultants. Inc. Published exclusively by WILEY-VCH Verlag GmbH & Co.KGaA) [source]