Comparing the oscillation phase in optical pump-probe spectra to ultrafast x-ray diffraction in the metal-dielectric SrRuO3/SrTiO3 superlattice
Comparing the oscillation phase in optical pump-probe spectra to ultrafast x-ray diffraction in the metal-dielectric SrRuO3/SrTiO3 superlattice
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DOI：
10.1103/physrevb.85.224302
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发表时间：
2012-06-19
影响因子：
3.7
通讯作者：
Bargheer, Matias
中科院分区：
文献类型：
--
作者：
Bojahr, Andre;Schick, Daniel;Bargheer, Matias
利用宽带全光泵浦探测光谱测量了金属介质超晶格的超快光响应。超晶格模式的观测相位取决于探测波长，这使得激发机制的分配变得困难。超快x射线衍射数据揭示了晶格的真实振荡相位随激发通量的变化而变化。光瞬态的影响关系证实了这一结果。我们建立了晶格动力学的线性链模型，并通过单元分解计算构成材料的应变相关介电函数，成功地模拟了宽带光学反射。
We measured the ultrafast optical response of metal-dielectric superlattices by broadband all-optical pump-probe spectroscopy. The observed phase of the superlattice mode depends on the probe wavelength, making assignments of the excitation mechanism difficult. Ultrafast x-ray diffraction data reveal the true oscillation phase of the lattice which changes as a function of the excitation fluence. This result is confirmed by the fluence dependence of optical transients. We set up a linear chain model of the lattice dynamics and successfully simulated the broadband optical reflection by unit-cell resolved calculation of the strain-dependent dielectric functions of the constituting materials.