排序方式: 共有59条查询结果,搜索用时 296 毫秒
1.
A. I. Artem’ev D. N. Klochkov K. Oganesyan Yu. V. Rostovtsev M. V. Fedorov 《Laser Physics》2007,17(10):1213-1216
The spatial amplification of a wave in a magnetostatic undulator with noncollinear electron and laser beams is studied in the framework of the dispersion relation for single-frequency and collective regimes. The dependence of the gain on the electron beam width is estimated with regard to the spatial boundedness of the beams. The laser power threshold at which the selection with respect to the transverse velocity is possible is obtained for a free-electron laser without inversion. 相似文献
2.
Coussement R Rostovtsev Y Odeurs J Neyens G Muramatsu H Gheysen S Callens R Vyvey K Kozyreff G Mandel P Shakhmuratov R Kocharovskaya O 《Physical review letters》2002,89(10):107601
A significant reduction of absorption for single gamma photons has been experimentally observed by studying M?ssbauer spectra of 57Fe in a FeCO3 crystal. The experimental results have been explained in terms of a quantum interference effect involving nuclear level anticrossing due to the presence of a combined magnetic dipole and electric quadrupole interaction. 相似文献
3.
We demonstrate a new approach to fast optical switching with a technique based on stimulated Raman adiabatic passage in which a laser pulse switches the probe field on and off via another coupling pulse. This new kind of optical switching is not limited by the decay rate of an excited state and can operate in the subnanosecond time domain. The experimental observation in Rb atomic vapor is in good agreement with numerical simulations. 相似文献
4.
Stopping light via hot atoms 总被引:5,自引:0,他引:5
We prove that it is possible to freeze a light pulse (i.e., to bring it to a full stop) or even to make its group velocity negative in a coherently driven Doppler broadened atomic medium via electromagnetically induced transparency (EIT). This remarkable phenomenon of the ultraslow EIT polariton is based on the spatial dispersion of the refraction index n(omega,k), i.e., its wave number dependence, which is due to atomic motion and provides a negative contribution to the group velocity. This is related to, but qualitatively different from, the recently observed light slowing caused by large temporal (frequency) dispersion. 相似文献
5.
We introduce the scattering problem in the case of one-dimensional space. The transmission factor is calculated for the whole domain of the potential energy. Connection with a field in interaction with a two-level quantum system is established for which the coupling parameter is considered to be explicitly time-dependent. 相似文献
6.
H. Li H. Chen M. A. Gubin Y. V. Rostovtsev V. A. Sautenkov M. O. Scully 《Laser Physics》2010,20(8):1725-1728
We have studied electromagnetically induced transparency (EIT) in diatomic cesium molecules in a vapor cell by using tunable
diode lasers. We have observed a sub-natural Λ-resonance in absorption molecular band B
1Π
u
− X
1Σ
g
+ at different cesium vapor pressures. The width of the EIT resonance shows a linear dependence on a cesium vapor pressure. 相似文献
7.
H. Li T.S. Varzhapetyan V.A. Sautenkov Y.V. Rostovtsev H. Chen D. Sarkisyan M.O. Scully 《Applied physics. B, Lasers and optics》2008,91(2):229-231
We have studied the selective reflection from the interface between a dense rubidium (Rb) atomic vapor and a transparent dielectric.
A remarkable narrowing of the spectrum, which can be used to improve the resolution of spectroscopy of dense media, has been
demonstrated. This narrowing results from the reduction of the dipole–dipole interaction between atoms when the Rb vapor is
excited by a strong pump laser. By using this technique, we have resolved the hyperfine structure of the Rb D2 line, which is hidden by collisional broadening.
PACS 32.70.Jz; 42.50.Ct; 34.80.Dp 相似文献
8.
Rostovtsev VV Bryman LM Junk CP Harmer MA Carcani LG 《The Journal of organic chemistry》2008,73(2):711-714
We have recently developed an improved synthetic route to 1,1,2,2-tetrafluoroethanesulfonic acid (HCF2CF2SO3H, TFESA) and explored the applications of this newly available superacid in catalysis. Low volatility, ease of handling, and a convenient 1H NMR handle make this acid an attractive alternative to triflic acid. TFESA can also be converted to several of its derivatives: anhydride, sulfonyl chloride, and sulfonyl fluoride, which provide a good entry point for the synthesis of aryl sulfonates. We prepared several aryl esters of 1,1,2,2-tetrafluoroethanesulfonic acid (aryl tetraflates) and showed that they can be used in a number of palladium-catalyzed coupling reactions (Suzuki, Heck, and Buchwald-Hartwig couplings). While the reactivity of tetraflates lies between that of triflates and chlorides, tetraflates appear to be more thermally stable. Additionally, the presence of a hydrogen atom in the tetraflate group facilitates monitoring of reactions and characterization of derivatives. 相似文献
9.
10.
Glezer A. M. Belyakov A. N. Rostovtsev G. R. Odnobokova M. V. Shchetinin I. V. Tomchuk A. A. 《Russian Physics Journal》2019,62(8):1518-1528
Russian Physics Journal - The electron backscatter diffraction, X-ray diffraction analysis, electromotive force instantaneous measurement, microhardness and coercive force measurement techniques... 相似文献