排序方式: 共有26条查询结果,搜索用时 171 毫秒
1.
Feltrin A Michelini F Staehli JL Deveaud B Savona V Toquant J Wang XL Ogura M 《Physical review letters》2005,95(17):177404
We study exciton and biexciton spectra in disordered semiconductor quantum wires by means of nanophotoluminescence spectroscopy. We demonstrate a close link between the exciton localization length along the wire and the occurrence of a biexciton spectral line. The biexciton signature appears only if the corresponding exciton state extends over more than a few tens of nanometers. We also measure a nonmonotonous variation of the biexciton binding energy with decreasing exciton localization length. This behavior is quantitatively well reproduced by the solution of the single-band Schr?dinger equation of the four-particle problem in a one-dimensional confining potential. 相似文献
2.
By comparing a kinetic and a thermal-equilibrium theory of polariton Bose-Einstein condensation, we study under what conditions the dynamical condensation under steady-state non-resonant pumping can approach thermal equilibrium. In particular, we study the dependence on two material parameters: the vacuum-field Rabi-splitting and the polariton radiative lifetime. When increasing the Rabi splitting, condensation takes place under strong non-equilibrium conditions, with dominating quantum fluctuations. Increasing the polariton lifetime above 10 ps at moderate Rabi splitting, instead, produces a quasi-equilibrium condensate at low exciton density, consistently with the picture of a weakly interacting Bose gas. 相似文献
3.
Lagoudakis KG Manni F Pietka B Wouters M Liew TC Savona V Kavokin AV André R Deveaud-Plédran B 《Physical review letters》2011,106(11):115301
The experimental investigation of spontaneously created vortices is of utmost importance for the understanding of quantum phase transitions towards a superfluid phase, especially for two-dimensional systems that are expected to be governed by the Berezinski-Kosterlitz-Thouless physics. By means of time-resolved near-field interferometry we track the path of such vortices, created at random locations in an exciton-polariton condensate under pulsed nonresonant excitation, to their final pinning positions imposed by the stationary disorder. We formulate a theoretical model that successfully reproduces the experimental observations. 相似文献
4.
Manni F Lagoudakis KG Pietka B Fontanesi L Wouters M Savona V André R Deveaud-Plédran B 《Physical review letters》2011,106(17):176401
We study the coherence and density modulation of a nonequilibrium exciton-polariton condensate in a one-dimensional valley with disorder. By means of interferometric measurements we evidence a modulation of the first-order coherence function and we relate it to a disorder-induced modulation of the condensate density, that increases as the pump power is increased. The nonmonotonic spatial coherence function is found to be the result of the strong nonequilibrium character of the one-dimensional system, in the presence of disorder. 相似文献
5.
Unambiguous and complete assignments of 1H and 13C NMR chemical shifts for five clerodane diterpenes, four of them isolated from Salvia splendens (salviarin, splendidin and splenolides A and B) and one obtained by acetylation of splenolide A, are presented. The assignments are based on 2D shift-correlated [1H,1H-COSY, 1H,13C-gHSQC-1J(C,H) and 1H,13C-gHMBC-nJ(C,H) (n=2 and 3)] and nuclear Overhauser effect (NOE) experiments. The conformation of the rings of these compounds is supported by the 3J(H,H) values and NOE results. 相似文献
6.
Salvatore Passannanti Maria Pia Paternostro Franco Piozzi Giuseppe Savona 《Journal of heterocyclic chemistry》1977,14(1):103-106
The synthesis of several isoearboslyrils is reported, including lorrnyl derivatives at (1-4, like nareiclasie aldehyde (I) and the homologous aldehyde (XV). 相似文献
7.
Intonti F Emiliani V Lienau C Elsaesser T Savona V Runge E Zimmermann R Nötzel R Ploog KH 《Physical review letters》2001,87(7):076801
Spatially resolved photoluminescence spectra of a single quantum well are recorded by near-field spectroscopy. A set of over four hundred spectra displaying sharp emission lines from localized excitons is subject to a statistical analysis of the two-energy autocorrelation function. An accurate comparison with a quantum theory of the exciton center-of-mass motion in a two-dimensional spatially correlated disordered potential reveals clear signatures of quantum mechanical energy level repulsion, giving the spatial and energetic correlations of excitons in disordered quantum systems. 相似文献
8.
The effect of irregular hole shape on the spectrum and radiation losses of a photonic crystal waveguide is studied using Bloch-mode expansion. Deviations from a circular hole are characterized by a radius fluctuation amplitude and correlation angle. It is found that the parameter that determines the magnitude of the effect of disorder is the standard deviation of the hole areas. Hence, for a fixed amplitude of the radius fluctuation around the hole, those effects are strongly dependent on the correlation angle of the irregular shape, which suggests how to potentially improve the quality of photonic crystal structures. 相似文献
9.
Z. Hradil A. Quattropani V. Savona P. Schwendimann 《Journal of statistical physics》1994,76(1-2):299-305
Polaritons in confined systems are introduced and their dispersion is calculated. The amount of squeezing of confined excitons-polaritons in GaAs quantum wells is evaluated. 相似文献
10.