Kundermann S, Saba M, Ciuti C, Guillet T, Oesterle U, Staehli J L, Deveaud B
Institut de Photonique et d'Electronique Quantiques, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
Phys Rev Lett. 2003 Sep 5;91(10):107402. doi: 10.1103/PhysRevLett.91.107402.
In a pump-probe experiment, we have been able to control, with phase-locked probe pulses, the ultrafast nonlinear optical emission of a semiconductor microcavity, arising from polariton parametric amplification. This evidences the coherence of the polariton population near k=0, even for delays much longer than the pulse width. The control of a large population at k=0 is possible although the probe pulses are much weaker than the large polarization they control. With rising pump power the dynamics of the scattering get faster. Just above threshold the parametric scattering process shows unexpected long coherence times, whereas when pump power is risen the contrast decays due to a significant pump reservoir depletion. The weak pulses at normal incidence control the whole angular emission pattern of the microcavity.
在泵浦-探测实验中，我们能够通过锁相探测脉冲控制半导体微腔由极化激元参量放大产生的超快非线性光发射。这证明了即使对于比脉冲宽度长得多的延迟，k = 0附近极化激元群体的相干性。尽管探测脉冲比它们所控制的大极化弱得多，但仍有可能控制k = 0处的大量群体。随着泵浦功率的增加，散射动力学变得更快。刚好高于阈值时，参量散射过程显示出意想不到的长相干时间，而当泵浦功率增加时，由于泵浦储能的显著耗尽，对比度下降。垂直入射的弱脉冲控制着微腔的整个角发射图案。
