High Pressure Drives 13-Fold Enhancement and Precise Control of Terahertz Emission in Layered GaTe

A new study published in Laser & Photonics Reviews demonstrates that high pressure can significantly boost and precisely tune terahertz (THz) radiation from the two-dimensional semiconductor gallium telluride (GaTe). Using a diamond anvil cell, researchers achieved a 13-fold enhancement in THz emission and directly uncovered the sequence of ultrafast processes that generate THz waves.

Terahertz radiation is widely used in spectroscopy, imaging, and materials research. It is typically produced when an ultrafast laser pulse hits a material, triggering rapid motions of electrons and the crystal lattice. However, different THz emission mechanisms—such as optical rectification and ultrafast transient currents—often overlap in time, making them difficult to separate.

A collaborative team from the Aerospace Information Research Institute of the Chinese Academy of Sciences (AIRCAS), the Hefei Institutes of Physical Science of CAS, and the Center for High Pressure Science & Technology Advanced Research used high pressure as a clean and powerful tuning method to manipulate GaTe's crystal and electronic structure. Their experiments not only amplified the THz wave output but also revealed a key time-domain signature: a phase shift of more than 150 femtoseconds showed that the transient current process occurs before optical rectification. This ordering became directly visible only under high pressure.

By combining simulations and first-principles calculations, the researchers found that pressure changes GaTe's intrinsic resonant frequency and initial charge distribution. These variations determine the amplitude, frequency, and phase of the emitted THz waves, offering a unified explanation for how different ultrafast mechanisms interact.

"This work shows that pressure is a powerful tool for controlling terahertz emission dynamics," said Prof. WANG Tianwu, a corresponding author of the study. "It also provides guidance for designing new THz-active materials, including those engineered through chemical-pressure–based doping."

The findings suggest that hydrostatic pressure can help probe and improve a wide range of emerging THz emitters—such as topological materials, spintronic materials, and heterostructures—enhancing their bandwidth, efficiency, and tunability. This research opens new possibilities for developing next-generation THz sources for scientific and technological applications.

The lattice structure of GaTe is continuously compressed under pressure, resulting in an approximately 13-fold enhancement of its terahertz emission, accompanied by a pronounced temporal advance exceeding 150 fs.(Image by AIRCAS)

The enhanced terahertz emission of GaTe under pressure originates from the pressure-induced increase in harmonic constraint frequency and the rise in transient current density. (Image by AIRCAS)