Coherent dynamics of bipolaritons in bulk CdS
Coherent dynamics of bipolaritons in bulk CdS
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CdS 中双极化子的相干动力学
DOI：
10.1103/physrevb.64.235206
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发表时间：
2001
影响因子：
3.7
通讯作者：
A. Ivanov
中科院分区：
文献类型：
--
作者：
Charlie;W. Langbein;U. Woggon;A. Ivanov
研究了CdS中光驱动激子-光子-双极化激元系统的相干动力学。利用后向散射四波混频（FWM）光谱，我们分析了激子分子的双光子偏振，并确定了退相时间T2为4.8 ps。 我们证明了分子介导的四波混频信号即使在χ（3）极限下也能在正的时间延迟下持续存在，这是由于第二脉冲诱导的相干极化激元的空间钉扎。将双极化激元模型推广到单轴半导体，计算了τXXrad = 2.8ps，证明了T_2 = 2 T_1的极限，并证明了CdS中激子分子的双极化激元表象。
The coherent dynamics of an optically driven exciton–photon–bipolariton system is studied in bulk CdS. Applying backward-scattering four-wave mixing (FWM) spectroscopy, we analyze the two-photon polarization associated with excitonic molecules and determine the dephasing time T2≃4.8 ps. We demonstrate that the molecule-mediated FWM signal persists at positive time delays even in the χ(3) limit, due to the spatial pinning of coherent polaritons induced by the second pulse. By generalizing the bipolariton model to uniaxial semiconductors, we calculate τXXrad≃2.8 ps, justify the T2=2T1 limit, and prove the bipolariton representation for excitonic molecules in CdS.