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排序方式: 共有82条查询结果,搜索用时 62 毫秒
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R.Kh. Zhukavin D.M. Gaponova A.V. Muravjov E.E. Orlova V.N. Shastin S.G. Pavlov H.-W. Hübers J.N. Hovenier T.O. Klaassen H. Riemann A.F.G. van der Meer 《Applied physics. B, Lasers and optics》2003,76(5):613-616
Terahertz stimulated emission of phosphorus donors in silicon optically excited by radiation from the free-electron laser
FELIX has been studied. It is found that a spectral line of the Si:P laser emission depends on pump frequency. Stimulated
emission arises on the 2p0→1s(E) intra-centre transition (21.2 meV) under resonant pumping of the 2p0 state and on the 2p0→1s(T2) transition (22.3 meV) under pumping of the 2p± or higher odd-parity donor states. The line shift is attributed to the Auger redistribution of the 1s(E)- and 1s(T2)-state populations.
Received: 7 November 2002 / Revised version: 7 April 2003 / Published online: 14 May 2003
RID="*"
ID="*"Corresponding author. Fax: +49-30/6705-55-07, E-mail: sergeij.pavlov@dlr.de
RID="**"
ID="**"On leave from: The Institute for Physics of Microstructures, Nizhny Novgorod, Russia 相似文献
3.
Near-infrared laser pulses of a compact 80-MHz femtosecond laser source at 800 nm, a mean power of 15-100 mW, 170-fs pulse width, and millisecond beam dwell times at the target have been used for multiphoton-mediated nanoprocessing of human chromosomes. By focusing of the laser beam with high-numerical-aperture objectives of a scanning microscope to diffraction-limited spots and with light intensities of terawatts per cubic centimeter, precise submicrometer holes and cuts in human chromosomes have been processed by single-point exposure and line scans. A minimum FWHM cut size of ~100 nm during a partial dissection of chromosome 1, which is below the diffraction-limited spot size, and a minimum material removal of ~0.003mum (3) were determined by a scanning-force microscope. The plasma-induced ablated material corresponds to ~1/400 of the chromosome 1 volume and to ~65x10(3) base pairs of chromosomal DNA. A complete dissection could be performed with FWHM cut sizes below 200 nm. High-repetition-frequency femtosecond lasers at low mean power in combination with high-numerical-aperture focusing optics appear therefore as appropriate noncontact tools for nanoprocessing of bulk and (or) surfaces of transparent materials such as chromosomes. In particular, the noninvasive inactivation of certain genomic regions on single chromosomes within living cells becomes possible. 相似文献
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Pavlov SG Zhukavin RK Orlova EE Shastin VN Kirsanov AV Hubers H Auen K Riemann H 《Physical review letters》2000,84(22):5220-5223
The observation of far-infrared stimulated emission from shallow donor transitions in silicon is reported. Lasing with a wavelength of 59 &mgr;m due to the neutral donor intracenter 2p(0)-->1s(E) transition in Si:P pumped by CO2 laser radiation is obtained. Populations of D0 and D- center states and the balance of the radiation absorption and amplification are theoretically analyzed. 相似文献
5.
Evaporation of emitter material from electrodes of fluorescent lamps has been measured by means of atomic absorption of Ba. A hollow-cathode discharge lamp served as background radiator. The arrangement is briefly described. Spot resolved measurements has been done in preheating and in discharge regimes. Essential results are dependence on evaporation rate and filament structure, evaporation and arising of cathode spot in discharge, and diminished evaporation regarding preheating. 相似文献
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Inversion of both the charge and the helicity of muon beams is considered as a possibility to determine the weak neutral-current couplings of muons, in particular the right-handed weak charge IR3(μ) and sin2θ without using the parton model. 相似文献
9.
Yang A Steger M Karaiskaj D Thewalt ML Cardona M Itoh KM Riemann H Abrosimov NV Churbanov MF Gusev AV Bulanov AD Kaliteevskii AK Godisov ON Becker P Pohl HJ Ager JW Haller EE 《Physical review letters》2006,97(22):227401
We resolve the remarkably sharp bound exciton transitions of highly enriched 28Si using a single-frequency laser and photoluminescence excitation spectroscopy, as well as photocurrent spectroscopy. Well-resolved doublets in the spectrum of the 31P donor reflect the hyperfine coupling of the electronic and nuclear donor spins. The optical detection of the nuclear spin state, and selective pumping and ionization of donors in specific electronic and nuclear spin states, suggests a number of new possibilities which could be useful for the realization of silicon-based quantum computers. 相似文献
10.
Auwärter W Klappenberger F Weber-Bargioni A Schiffrin A Strunskus T Wöll C Pennec Y Riemann A Barth JV 《Journal of the American Chemical Society》2007,129(36):11279-11285
We present a combined low-temperature scanning tunneling microscopy and near-edge X-ray adsorption fine structure study on the interaction of tetrapyridyl-porphyrin (TPyP) molecules with a Cu(111) surface. A novel approach using data from complementary experimental techniques and charge density calculations allows us to determine the adsorption geometry of TPyP on Cu(111). The molecules are centered on "bridge" sites of the substrate lattice and exhibit a strong deformation involving a saddle-shaped macrocycle distortion as well as considerable rotation and tilting of the meso-substituents. We propose a bonding mechanism based on the pyridyl-surface interaction, which mediates the molecular deformation upon adsorption. Accordingly, a functionalization by pyridyl groups opens up pathways to control the anchoring of large organic molecules on metal surfaces and tune their conformational state. Furthermore, we demonstrate that the affinity of the terminal groups for metal centers permits the selective capture of individual iron atoms at low temperature. 相似文献