Search results for "SAPPHIRE"
showing 10 items of 114 documents
Effect of reactive ion beam etching on the photoluminescence of CdTe epitaxial layers
2008
http://link.aip.org/link/?JAPIAU/103/056108/1
Thermal conductivity of thermoelectric Al-substituted ZnO thin films
2013
ZnO:Al thin films with a low electrical resistivity were grown by magnetron sputtering on sapphire substrates. The cross-plane thermal conductivity (κ = 4.5 ± 1.3 W/mK) at room temperature is almost one order of magnitude lower than for bulk materials. The thermoelectric figure of merit ZT at elevated temperatures was estimated from in-plane power factor and the cross-plane thermal conductivity at room temperature. It is expected that the thermal conductivity drops with increasing temperature and is lower in-plane than cross-plane. Consequently, the thin film ZT is at least three times higher than for bulk samples at intermediate temperatures. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinh…
Solar blind detectors based on AlGaN grown on sapphire
2005
Solar blind detectors have been fabricated based on AlGaN heterostructures grown on sapphire by molecular beam epitaxy or chemical vapour deposition. MSM and Schottky detectors were investigated. High performance devices have been obtained thanks to an optimization of the material crystalline quality (including the suppression of cracks) and of the process. We show that the spectral limitations of MSM detectors are dictated by intrinsic phenomena that are analysed in details while the responsivity and detectivity also depends on the technological process with a special emphasis on the geometry of finger and contact pads. One and two dimensional arrays have been fabricated and preliminary re…
Flashlamp-pumped Ti:Sapphire laser: Influence of the rod figure of merit and Ti3+ concentration
1994
A flashlamp-pumped Ti:Sapphire laser is tested with rods of various Figures of Merit (FOM from 100 to 800) and Ti3+ concentrations (0.1 and 0.15% by weight) and we measured the laser energy dependence as a function of these parameters. Output energies above 2 J are obtained without dye converter, leading to a 1.8% overall efficiency and a 2.2% slope efficiency. The effects of pump pulse duration by variation of the discharge capacitance are also monitored.
Comparison of the F-type center thermal annealing in heavy-ion and neutron irradiated Al2O3 single crystals
2018
Abstract The optical absorption and thermally stimulated luminescence of Al2O3 (sapphire) single crystals irradiated with swift heavy ions (SHI) 238U with energy 2.4 GeV is studied with the focus on the thermal annealing of the F-type centers in a wide temperature range of 400–1500 K. Its theoretical analysis allows us to obtain activation energies and pre-exponentials of the interstitial oxygen ion migration, which recombine with both types of immobile electron centers (F and F+ centers). A comparison of these kinetics parameters with literature data for a neutron-irradiated sapphire shows their similarity and thus supports the use of SHI-irradiation for modeling the neutron irradiation.
Compact setup for spin-, time-, and angle-resolved photoemission spectroscopy.
2020
Review of scientific instruments 91(6), 063001 (2020). doi:10.1063/5.0004861
Laser systems for on-line laser ion sources
2008
Since its initiation in the middle of the 1980s, the resonant ionization laser ion source has been established as a reliable and efficient on-line ion source for radioactive ion beams. In comparison to other on-line ion sources it comprises the advantages of high versatility for the elements to be ionized and of high selectivity and purity for the ion beam generated by resonant laser radiation. Dye laser systems have been the predominant and pioneering working horses for laser ion source applications up to recently, but the development of all-solid-state titanium:sapphire laser systems has nowadays initiated a significant evolution within this field. In this paper an overview of the ongoing…
Characterization of a 10Hz double-pulse non-normal incidence pumped transient collisional Ni-like molybdenum soft x-ray laser for applications
2009
Stable and reliable operation of a nickel-like molybdenum transient collisional soft x-ray laser at 18.9 nm demonstrated and studied with a 10Hz Ti:sapphire laser system proves the suitability of the double-pulse non-normal incidence pumping geometry for table-top high repetition soft x-ray lasers and broadens the attractiveness of x-ray lasers as sources of coherent radiation for various applications. X-ray laser emission with pulse energies well above 1 μJ is obtained for several hours at 10Hz repetition-rate without re-alignment under optimized double pumping pulse parameters including energy ratio, time delay, pulse duration and line focus width.
Continuous-wave backward frequency doubling in periodically poled lithium niobate
2010
We report on backward second-harmonic-generation in bulk periodically poled congruent lithium niobate with a 3.2 microns period. A tunable continuous-wave Ti:sapphire laser allowed us exciting two resonant quasi-phase-matching orders in the backward configuration. The resonances were also resolved by temperature tuning and interpolated with standard theory to extract relevant information on the sample.
Ultra Trace Determination Scheme for26Al by High-Resolution Resonance Ionization Mass Spectrometry using a Pulsed Ti:Sapphire Laser
2008
We propose an ultra trace analysis approach for 26Al by high-resolution Resonance Ionization Mass Spectrometry (RIMS) using a pulsed narrow band-width Ti:Sapphire laser. For ensuring efficient ionization and high isotopic selectivity in RIMS of Al, we developed an injection seeded pulsed Ti:Sapphire laser with high repetition rate operation at up to 10 kHz. The laser produced an output power of 2 W and a spectral band-width of ~20 MHz with a repetition rate of 7 kHz. A first demonstration of its performance was done by detecting stable 27Al using RIMS.