Zhang Shunnong, Jin Zuanming, Liu Xiumei, Zhao Wanying, Lin Xian, Jing Chao, Ma Guohong
Opt Lett. 2017 Aug 15;42(16):3080-3083. doi: 10.1364/OL.42.003080.
We report the broadband terahertz (THz) radiation in ferromagnetic half-metallic Heusler alloy CoMnSn thin film upon the irradiation of a femtosecond laser pulse at room temperature. The magnetic-, sample symmetry-, and pump fluence-dependent THz emission reveals that the THz radiation is originated from the magnetic-dipole radiation, i.e., the light-induced subpicosecond demagnetization. In addition, by optical pump-THz probe spectroscopy, we found that the photoexcited increase of the scattering rate of hot carriers thereby leads to the photoinduced negative THz conductivity in CoMnSn thin film.
我们报道了在室温下，飞秒激光脉冲辐照铁磁半金属赫斯勒合金CoMnSn薄膜时产生的宽带太赫兹（THz）辐射。与磁性、样品对称性和泵浦通量相关的太赫兹发射表明，太赫兹辐射源自磁偶极辐射，即光诱导的亚皮秒退磁。此外，通过光泵浦-太赫兹探测光谱，我们发现热载流子散射率的光激发增加从而导致CoMnSn薄膜中光诱导的负太赫兹电导率。
