Spectral dependence of time-resolved coherent and incoherent second-harmonic response of ferromagnetic Gd(0001)
Spectral dependence of time-resolved coherent and incoherent second-harmonic response of ferromagnetic Gd(0001)
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铁磁 Gd(0001) 时间分辨相干和非相干二次谐波响应的光谱依赖性
DOI：
10.1364/josab.22.000204
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发表时间：
2005
影响因子：
1.9
通讯作者：
E. Matthias
中科院分区：
文献类型：
--
作者：
A. Melnikov;I. Radu;U. Bovensiepen;K. Starke;M. Wolf;E. Matthias
利用35 fs的激光脉冲和1.44 ~ 1.68 eV的光子能量研究了Gd（0001）铁磁表面的二次谐波（SH）产生。在泵浦-探测模式下，测量了前3 ps的SH场，并分析了时间演化，包括相干声子和磁振子的贡献。所有的数据都揭示了随波长的强烈变化，这与SH磁衬度相关，并且可以很好地用Gd（0001）交换分裂表面态来解释。在SH干涉仪的能量分裂为13毫电子伏，被发现是由于约3太赫兹的相干声子的表面状态的频率调制。
Second-harmonic (SH) generation at the ferromagnetic Gd(0001) surface was investigated with 35-fs laser pulses and photon energies between 1.44 and 1.68 eV. In pump-probe mode the SH field was measured during the first 3 ps, and the time evolution, including contributions from coherent phonons and magnons, was analyzed. All data reveal strong changes with wavelength, which correlate with the SH magnetic contrast and can be well explained by the Gd(0001) exchange-split surface state. In SH interferometry an energy splitting of 13 meV was found that is attributed to a frequency modulation of the surface state by coherent phonons of approximately 3 THz.