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Krainer L Nodop D Spühler GJ Lecomte S Golling M Paschotta R Ebling D Ohgoh T Hayakawa T Weingarten KJ Keller U 《Optics letters》2004,29(22):2629-2631
We demonstrate a compact, diode-pumped Nd:GdVO4 laser with a repetition rate of 9.66 GHz and 0.5-W average output power. The laser is passively mode locked with a semiconductor saturable absorber mirror (SESAM), yielding 12-ps-long sech2-shaped pulses. For synchronization of the pulse train to an external reference clock, the SESAM is mounted on a piezoelectric transducer. With an electronic feedback loop of only a few kilohertz loop bandwidth we achieved a rms timing jitter of 146 fs (integrated from 10 Hz to 10 MHz). This is an upper limit because it is mostly limited by the measurement system. The laser setup with a simple linear cavity has a footprint of only 130 mm x 30 mm. 相似文献
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CM Thaker S Rayaprol Krushna Mavani DS Rana MS Sahasrabudhe SI Patil DG Kuberkar 《Pramana》2002,58(5-6):1035-1039
The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO3 perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good
example of these properties is (La1−2x
Pr
x
Ca
x
)MnO3 (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T
c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using
X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for
understanding the structural, transport and magnetic properties are discussed in detail. 相似文献
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§ 1.Introduction WearegivenkindependentWishartdensitiesofthe (p +q)× (p +q)randomsymmetricpositivedefinitematricesG1,… ,Gktobeg(Gi) =Kexp -12 trR- 1i Gi Gi12 (ni- q-p- 1) ,(1 )wherei=1 ,… ,k,andRidenotesthepopulationcorrelationmatrixofthei thpopulationandKasagenericletterdenote… 相似文献
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Towards wafer-scale integration of high repetition rate passively mode-locked surface-emitting semiconductor lasers 总被引:3,自引:0,他引:3
D.?Lorenser H.J.?UnoldEmail author D.J.H.C.?Maas A.?Aschwanden R.?Grange R.?Paschotta D.?Ebling E.?Gini U.?Keller 《Applied physics. B, Lasers and optics》2004,79(8):927-932
One of the most application-relevant milestones that remain to be achieved in the field of passively mode-locked surface-emitting semiconductor lasers is the integration of the semiconductor absorber into the gain structure, enabling the realization of ultra-compact high-repetition-rate laser devices suitable for wafer-scale integration. We have recently succeeded in fabricating the key element in this concept, a quantum-dot-based saturable absorber with a very low saturation fluence, which for the first time allows stable mode locking of surface-emitting semiconductor lasers with the same mode areas on gain and absorber. Experimental results at high repetition rates of up to 30 GHz are shown. PACS 42.55.Px; 42.60.Fc; 42.82.Gw 相似文献
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Structural and mechanical properties of spark plasma sintered n‐ and p‐type bismuth telluride alloys
Harald Böttner Dirk G. Ebling A. Jacquot J. König L. Kirste J. Schmidt 《固体物理学:研究快报》2007,1(6):235-237
Spark Plasma Sintering (SPS) is used for the fabrication of wafers of n‐ and p‐type thermoelectric V2VI3 materials. The SPS process did not change the overall chemical composition. X‐ray diffraction analysis and the electron backscattered selected area diffraction prove the preferential orientation after the SPS procedure expecting anisotropic thermoelectric prop‐ erties. The mechanical properties of the SPS material are enormously enhanced, so that the fabrication of thin wafers with only 100 µm thickness suitable for the development of Peltier devices with high cooling power density will be possible. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Borgwarth K Ricken C Ebling DG Heinze J 《Analytical and bioanalytical chemistry》1996,356(3-4):288-294
Resolution studies of scanning electrochemical microscopy (SECM) have been performed in the feedback mode and in the generator/collector mode at circular model structures. A quantitative correlation of the loss in resolution and the increase in distance between tip and sample is found. Measuring a band electrode of just 500 nm width, the high sensitivity of the SECM in identifying chemically active sites is proven. Applied to polymer samples, the chemical composition was determined in the feedback mode at high lateral resolution. The difference in electrical conductivity allows one to distinguish between doped and undoped parts of a polyaniline film. By scanning above a blend consisting of polypyrrole and polypropylene, a map of the local chemical composition was obtained. In this context, the influence of the tip overpotential on the image is discussed. 相似文献
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H. Meincke D. G. Ebling J. Heinze M. Tacke H. Böttner 《Analytical and bioanalytical chemistry》1999,365(1-3):147-149
Lead selenide is a narrow gap semiconductor material. It finds applications in infrared emitting and detecting devices. Their performance is closely related to charge carrier recombination at the surface, which can be reduced by passivation, e.g. due to PbSeO3 formation by anodic oxidation in alkaline solutions. In dependence on the pretreatment of the surface, two different types of oxide formation were observed. To determine the electronic properties of the anodic oxide, the wavelength dependence of the photocurrent was investigated. The energy of the band gap of both types of anodic oxide on PbSe has been determined to be 2.4 eV for the direct and 1.8 eV for the indirect band gap. A weakening of the photocurrent generated in the bulk (PbSe) due to scattering or absorption within the oxide confirms the potential dependence of the oxide thickness for a high field growth mechanism. 相似文献
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