Advancements in Terahertz Phonon Engineering Using Van der Waals Heterostructures

Recent advancements in terahertz (THz) phonon engineering have been achieved through the use of van der Waals heterostructures, as detailed in a paper by Yoseob Yoon and colleagues. The research focuses on the efficient generation, detection, and manipulation of THz phonons, which are crucial for developing high-speed acoustic filters and modulators. The authors highlight the use of few-layer graphene (FLG) as an ultrabroadband phonon transducer, capable of converting femtosecond near-infrared pulses into acoustic phonon pulses with a spectral range extending up to 3 THz.

A significant aspect of this research is the integration of a monolayer of tungsten diselenide (WSe₂) as a sensor, which benefits from strong light-matter interactions and exciton-phonon coupling. This combination allows for high-fidelity readouts and enables THz phononic spectroscopy by detecting responses to mechanical waves.

The study also demonstrates the creation of high-quality THz phononic cavities. Notably, the research reveals that embedding WSe₂ in hexagonal boron nitride (hBN) can effectively block THz phonon transmission. By comparing experimental measurements to a nanomechanical model, the researchers were able to derive force constants at the heterointerfaces, providing deeper insights into the material properties.

These findings could pave the way for the development of THz phononic metamaterials, which may lead to ultrabroadband acoustic filters and modulators, as well as new approaches for thermal engineering. The implications of this research extend to various applications in quantum circuits and advanced communication technologies, where enhanced bandwidth and operational temperatures are essential.

For further details, the full paper can be accessed at arXiv:2310.04939.