Ramakrishna S, Seideman Tamar
Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
J Chem Phys. 2006 Jun 28;124(24):244503. doi: 10.1063/1.2209234.
We extend a recently formulated coherence spectroscopy of dissipative media [J. Chem. Phys. 122, 084502 (2005)] from the stationary excitation limit to the time domain. Our results are based on analytical and numerical solutions of the quantum Liouville equation within the Bloch framework. It is shown that the short pulse introduces a new, controllable time scale that allows better insight into the relation between the coherence signal and the phase properties of the material system. We point to the relation between the time-domain coherence spectroscopy and the method of interferometric two-photon photoemission spectroscopy, and propose a variant of the latter method, where the two time-delayed excitation pathways are distinguishable, rather than identical. In particular, we show that distinguishability of the two excitation pathways introduces the new possibility of disentangling decoherence from population relaxation.
我们将最近提出的耗散介质相干光谱学[《化学物理杂志》122, 084502 (2005)]从稳态激发极限扩展到了时域。我们的结果基于布洛赫框架内量子刘维尔方程的解析解和数值解。结果表明，短脉冲引入了一个新的、可控的时间尺度，这使得我们能够更好地洞察相干信号与材料系统相位特性之间的关系。我们指出了时域相干光谱学与干涉双光子光发射光谱学方法之间的关系，并提出了后一种方法的一个变体，其中两条时间延迟的激发路径是可区分的，而不是相同的。特别是，我们表明两条激发路径的可区分性带来了将退相干与布居弛豫区分开的新可能性。
