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M Wavelength (m + wavelength)

Distribution by Scientific Domains
Physics and Astronomy60%

Selected Abstracts

Transmission spectra of crystals at elevated temperatures for the calculation of internal radiant heat transport during crystal growth , Part 1: The spectrometer and its performance

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2003
D. Schwabe
Abstract We report the construction, operation and performance of a transmission spectrometer for the visible to the IR (up to 3.5 ,m wavelength) to measure crystals up to a temperature of 1400 °C. The spectral resolution is almost comparable to that of a commercial spectrometer. The performance of the spectrometer and some problems are demonstrated by spectra of YAG : Nd at different temperatures. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Thermal Barrier Coatings Design with Increased Reflectivity and Lower Thermal Conductivity for High-Temperature Turbine Applications

INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 2 2006
Matthew J. Kelly
High reflectance thermal barrier coatings consisting of 7% Yittria-Stabilized Zirconia (7YSZ) and Al2O3 were deposited by co-evaporation using electron beam physical vapor deposition (EB-PVD). Multilayer 7YSZ and Al2O3 coatings with fixed layer spacing showed a 73% infrared reflectance maxima at 1.85 ,m wavelength. The variable 7YSZ and Al2O3 multilayer coatings showed an increase in reflection spectrum from 1 to 2.75 ,m. Preliminary results suggest that coating reflectance can be tailored to achieve increased reflectance over a desired wavelength range by controlling the thickness of the individual layers. In addition, microstructural enhancements were also used to produce low thermal conductive and high hemispherical reflective thermal barrier coatings (TBCs) in which the coating flux was periodically interrupted creating modulated strain fields within the TBC. TBC showed no macrostructural differences in the grain size or faceted surface morphology at low magnification as compared with standard TBC. The residual stress state was determined to be compressive in all of the TBC samples, and was found to decrease with increasing number of modulations. The average thermal conductivity was shown to decrease approximately 30% from 1.8 to 1.2 W/m-K for the 20-layer monolithic TBC after 2 h of testing at 1316°C. Monolithic modulated TBC also resulted in a 28% increase in the hemispherical reflectance, and increased with increasing total number of modulations. [source]

Ba(Mg,Zr,Ta)O3:Nd3+ fine-grained ceramics: a novel laser-gain material with disordered structure for high-power laser systems

LASER PHYSICS LETTERS, Issue 4 2009
A.A. Kaminskii
Abstract Nd3+ -ion doped Ba(Mg,Zr,Ta)O3 ceramics is introduced as a new gain crystalline materials for lasers and laser amplifiers. By pumping laser-diode radiation at 300 K its CW stimulated emission at 1.0754 ,m wavelength was recorded. Some optical, spectroscopic and mechanical properties were measured as well. (© 2009 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Passive mode-locking with carbon nanotube saturable absorber in Nd:GdVO4 and Nd:Y0.9Gd0.1VO4 lasers operating at 1.34 ,m

LASER PHYSICS LETTERS, Issue 9 2007
S.V. Garnov
Abstract A flash-lamp pumped passively mode-locked neodymium-doped vanadate lasers operated at 1.34 ,m wavelength have been developed using a novel saturable absorber consisted of single-wall carbon nanotubes incorporated in a polymer matrix. Laser pulses with the output energy up to 50 ,J and the duration of 30 ps were generated. (© 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Infrared microstrip dipole antennas,FDTD predictions versus experiment

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2001
Iulian Codreanu
Abstract We report on the successful use of niobium microbolometers coupled to microstrip dipole antennas for the detection of midinfrared radiation. Measurements of the detector response versus antenna length performed at the 10.6 ,m wavelength allowed us to identify the first three current-wave resonances along the antenna arms. The detector response was also measured as a function of the radiation wavelength in the 9,11 ,m spectral domain. Excellent agreement between the experimental results and finite-difference time-domain (FDTD) predictions was obtained. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 381,383, 2001. [source]