Coherent terahertz magnon-phonon three-wave mixing in a layered antiferromagnet.

Coherent magnon-phonon three-wave mixing observed in FePS3, revealing nonlinear interactions crucial for quantum control in layered antiferromagnets.

• Why it matters: Understanding and harnessing collective excitations like magnons and phonons are vital for developing quantum technologies, yet direct observation of their nonlinear dynamics has been limited.
• What they did: Using double-terahertz-pump optical-probe spectroscopy, the study identified second- and third-order nonlinear responses, including sum- and difference-frequency generation, in 2D coherent spectra of FePS3.
• The result: This work demonstrates the potential to entangle magnetic and vibrational excitations, paving the way for advanced quantum control and hybrid quantum systems in the terahertz frequency range.