Magnon-polaritons are shown to play a dominant role in the propagation of terahertz (THz) waves through TmFeO₃ orthoferrite, if the frequencies of the waves are in the vicinity of the quasi-antiferromagnetic spin resonance mode. Both time-domain THz transmission and emission spectroscopies reveal clear beatings between two modes with frequencies slightly above and slightly below this resonance, respectively. Rigorous modeling of the interaction between the spins of TmFeO₃ and the THz light shows that the frequencies correspond to the upper and lower magnon-polariton branches. Our findings reveal the previously ignored importance of propagation effects and polaritons in such heavily debated areas as THz magnonics and THz spectroscopy of electromagnons. It also shows that future progress in these areas calls for an interdisciplinary approach at the interface between magnetism and photonics.

中文翻译：

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TmFeO3 中的太赫兹磁振子极化子

如果波的频率在准反铁磁自旋共振模式附近，则显示磁子极化子在太赫兹 (THz) 波通过 TmFeO ₃正铁氧体的传播中起主导作用。时域太赫兹传输和发射光谱均显示两种模式之间的明显跳动，频率分别略高于和略低于该共振。_{TmFeO 3}自旋之间相互作用的严格建模太赫兹光显示频率对应于上部和下部磁振子极化子分支。我们的研究结果揭示了传播效应和极化子在诸如太赫兹磁子学和电磁铁的太赫兹光谱等备受争议的领域中先前被忽视的重要性。它还表明，这些领域的未来进展需要在磁学和光子学之间的界面上采用跨学科方法。