Opt Lett. 2023 Apr 15;48(8):2054-2057. doi: 10.1364/OL.485966.
The dynamic control of magnetization by short laser pulses has recently attracted interest. The transient magnetization at the metallic magnetic interface has been investigated through second-harmonic generation and the time-resolved magneto-optical effect. However, the ultrafast light-driven magneto-optical nonlinearity in ferromagnetic heterostructures for terahertz (THz) radiation remains unclear. Here, we present THz generation from a metallic heterostructure, Pt/CoFeB/Ta, which is ascribed to an ∼6-8% contribution from the magnetization-induced optical rectification and an ∼94-92% contribution from both spin-to-charge current conversion and ultrafast demagnetization. Our results show that THz-emission spectroscopy is a powerful tool to study the picosecond-time-scale nonlinear magneto-optical effect in ferromagnetic heterostructures.
短激光脉冲对磁化强度的动态控制最近引起了人们的兴趣。通过二次谐波产生和时间分辨磁光效应研究了金属磁界面的瞬态磁化。然而，太赫兹（THz）辐射铁磁异质结构中超快光驱动的磁光非线性仍然不清楚。在这里，我们展示了来自金属异质结构 Pt/CoFeB/Ta 的 THz 产生，这归因于约 6-8%来自磁化诱导光整流的贡献和约 94-92%来自自旋到电荷电流转换和超快退磁的贡献。我们的结果表明，太赫兹发射光谱是研究铁磁异质结构中皮秒时间尺度非线性磁光效应的有力工具。
