Terahertz Magnon-Polaritons in TmFeO₃

Abstract

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.

Engineering terahertz surface magnon-polaritons in hyperbolic antiferromagnets

“…At lower frequencies, 5-50 GHz, magnetic materials are used in a variety of signal-processing devices, including isolators, bandpass filters [33], band stop filters [34], and circulators [35]. Our findings indicate that antiferromagnets could play a similar role for signal processing in the 500-GHz to 2-THz frequency range [36,37]. Such terahertz magnons may also be used for sensing, working as an analog to the current plasmonic technologies [38,39].…”

Routes to Low-Energy Magnetic Electronics

“…The spin resonance study in antiferromagnets calls for interdisciplinary approach due to the very high resonance frequencies (in the range of terahertz) and complex nature of magnetic excitations: magnonpolaritons 15 and electromagnons. 16 Electromagnons (electro-active magnons) are the elementary excitation of hybrid nature: magnons generated by the high frequency electric eld.…”

Numerically Denoising Thermally Tunable and Thickness‐Dependent Terahertz Signals in ErFeO3 Based on Bézier Curves and B‐Splines

“…In 2018, Ma and co‐workers reported the magnon‐polariton beating in their signals taken for thick samples. [ 7 ] This physical way provides an outstanding idea for us to reduce the noise.…”

“…However, there is still a great deal of work needed to be done in the terahertz band compared with its two nearest neighbor electromagnetic ranges due to the lack of numerous functional materials in this frequency region. [4][5][6][7][8][9][10] A THz time-domain system (THz-TDS) is a typical platform for measuring short electromagnetic waves. [11,12] A terahertz spectropic research of magnetic-field dependence of strongly anisotropic spin reorientation transition in NdFeO 3 was reported [13] and later they reported THz transient probing magnetic field tuning of spin resonance in TmFeO 3 single crystal in 2020.…”

“…However, there is still a great deal of work needed to be done in the terahertz band compared with its two nearest neighbor electromagnetic ranges due to the lack of numerous functional materials in this frequency region. [ 4–10 ]…”