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- PublicationMétadonnées seulement
- PublicationMétadonnées seulement240-fs pulses with 22-W average power from a mode-locked thin-disk Yb: KY (WO< sub> 4)< sub> 2 laser(2002)
;Brunner, Felix ; ;Innerhofer, Edith ;Morier-Genoud, F ;Paschotta, Rüdiger ;Kisel, VE ;Shcherbitsky, VG ;Kuleshov, NV ;Gao, JContag, K
- PublicationMétadonnées seulement
- PublicationMétadonnées seulementUltra-stable microwave generation with a diode-pumped solid-state laser in the 1.5-?m range(2013)
; ; ; ; ;Grop, Serge ;Dubois, Benoît ;Giordano, Vincent
- PublicationMétadonnées seulementHigh performance vapour-cell frequency standards(: Journal of Physics: Conference Series 723, 2015-10-27)
; ; ; ; ; ;We report our investigations on a compact high-performance rubidium (Rb) vapour-cell clock based on microwave-optical double-resonance (DR). These studies are done in both DR continuous-wave (CW) and Ramsey schemes using the same Physics Package (PP), with the same Rb vapour cell and a magnetron-type cavity with only 45 cm3 external volume. In the CW-DR scheme, we demonstrate a DR signal with a contrast of 26% and a linewidth of 334 Hz; in Ramsey-DR mode Ramsey signals with higher contrast up to 35% and a linewidth of 160 Hz have been demonstrated. Short-term stabilities of 1.4×10^-13 τ^-1/2 and 2.4×10^-13 τ^-1/2 are measured for CW-DR and Ramsey-DR schemes, respectively. In the Ramsey-DR operation, thanks to the separation of light and microwave interactions in time, the light-shift effect has been suppressed which allows improving the long-term clock stability as compared to CW-DR operation. Implementations in miniature atomic clocks are considered.
- PublicationAccès libreStatic Adsorption, by activated Carbons, of vapour Mixtures corresponding to immiscible Liquids(1999)
;Wintgens, D. ;Lavanchy, André
- PublicationMétadonnées seulementSi-Interdiffusion in heavily doped AIN-GaN-based quantum well intersubband photodetectors(2011)
; ; ;Martin, Denis ;Grandjean, Nicolas ;Kotsar, YuliaMonroy, EvaWe demonstrate the effect of rapid thermal annealing on heavily Si-doped AlN/GaN quantum wells. After 1000 °C annealing during 5, 10, and 20 min, the dominant effect was interdiffusion of Si rather than intermixing between the Al and Ga atoms. Both their original value and the magnitude of the changes after annealing reveal that intersubband absorption and photovoltage are related to two different optical transitions as follows: absorption occurs in the 1 to 2 intersubband transition, whereas photovoltage is due to a subsequent process from the 1 to 2 and the manifold of 2 to higher order transitions. © 2011 American Institute of Physics.
- PublicationMétadonnées seulementConversion of ethylene into ethylidyne on a mixed-metal cluster: synthesis and structure of IrRu4(CO)(15)(mu(4)-CH3)(1999)
;Haak, Susanne ;Neels, Antonia ;The thermal reaction of the tetranuclear cluster HIrRu3(CO)(13) with ethylene in hexane (90 degrees C, 2 bar) affords, in addition to H3IrRu3(CO)(12), the pentanuclear cluster HIrRu4(CO)(15)(mu(4)-C-CH3) (1) in which the ethylidyne ligand is coordinated through a carbon atom to the four ruthenium atoms in the IrRu4 core. In this reaction, the CH2=CH2 molecule has been transformed into a C-CH3 moiety coordinated as a mu(4)-ligand to the cluster. (C) 1999 Elsevier Science S.A. All rights reserved.
- PublicationMétadonnées seulementApplication of the novel tandem process Diels-Alder reaction/Ireland-Claisen rearrangement to the synthesis of rac-juvabione and rac-epijuvabione(2000-1-12)
;Soldermann, Nicolas ;Velker, Joerg ;Vallat, Olivier ;The novel tandem process Diels-Alder reaction/Ireland-Claisen rearrangement shows a high diastereoselectivity for the Ireland-Claisen rearrangement starting from the endo-product of the Diels-Alder reaction. Based on this mechanistic knowledge, the novel tandem process could be applied to the synthesis of rac-juvabione.
- PublicationMétadonnées seulementMetal-framework degradation reactions of the mixed-metal cluster anions [M3Ir(CO)(13)](-) (M=Ru, Os) with bis(diphenylphosphino)methane and with tricyclohexylphosphine: synthesis and structure of HRu2Ir(CO)(5)(dppm)(3), HRu2Ir(CO)(6)(PCy3)(3), H2Os2Ir2(CO)(10)(PCy3)(2) and H3Os3Ir(CO)(8)(PCy3)(3)(1999)
;Haak, Susanne ; ;Neels, AntoniaThe mixed-metal cluster anions [M3Ir(CO)(13)](-) (M=Ru, Os) react in methanol under metal-framework degradation with bis(diphenylphosphino)methane (dppm) or tricyclohexylphosphine (PCy3) to give a series of neutral tri- and tetranuclear mixed-metal clusters. The reaction of [M3Ir(CO)(13)](-) (M=Ru, Os) with dppm leads to the phosphine-substituted hydrido derivatives HRu2Ir(CO)(5)(dppm)(3) (1) and HOs2Ir(CO)(5)(dppm), (2), respectively. The two 48e clusters show a triangular arrangement of the M2Ir skeleton. The dppm ligands are coordinated in bridging positions over each metal-metal edge; the hydride is bonded terminally to the iridium atom. Cluster degradation is also observed by treating [Ru3Ir(CO)(13)](-) with PCy3 in methanol, giving the highly electron-deficient (44e) mixed-metal cluster HRu2Ir(CO)(6)(PCy3)(3) (3). The reaction of the osmium homologue [Os3Ir(CO)(13)](-) with PCy3 under the same conditions leads to a mixture of the neutral tetranuclear clusters H2Os2Ir2(CO)(10)(PCy3)(2) (4) and H3Os3Ir(CO)(8)(PCy3)(3) (5). Both clusters, 4 and 5 still have a tetrahedral metal core like the starting cluster anion but in 4 an osmium atom has been replaced by an iridium atom. The molecular structures of 1, 3, 4 and 5 were confirmed by single-crystal X-ray structure analyses. (C) 1999 Elsevier Science Ltd. All rights reserved.