Revolution in the terahertz range: New materials for compact light!

Revolution in the terahertz range: New materials for compact light!

An international research project led by Josh Caldwell from Vanderbilt University and Alexander Paarmann from the Fritz Haber Institute has made groundbreaking advances in terahertz technology. In collaboration with Prof. Lukas M. Eng from the Technical University of Dresden, researchers demonstrated the compression of terahertz (THz) light to nanoscale dimensions.

The results, published September 15, 2025 in the journal Nature Materials, show how hafnium dichalcogenides (HfX2, where X = S or Se) enable significant compression of THz light. Wavelengths of over 50 micrometers were reduced to less than 250 nanometers, which resulted in minimal energy loss. This compression is comparable to confining ocean waves in a teacup, illustrating the scale and efficiency of this technology.

In the focus of research

The challenge of integrating THz technology into compact devices stems from the long wavelength of THz light. While traditional materials have struggled to effectively compress light in the THz range, the novel hafnium dichalcogenide layered material offers a promising solution. The research aims to study the interaction of light and matter at the nano to atomic level, which has far-reaching implications for nonlinear optics.

The research team used the optical near-field microscope, which was developed in cooperation between the TU Dresden and the Helmholtz Center Dresden-Rossendorf. One of the main intentions is to develop ultra-compact THz resonators and waveguides that could potentially revolutionize research with 2D materials through integration into van der Waals heterostructures.

Applications and technical developments

The potential applications of this technology are promising, ranging from improvements in optoelectronic devices such as infrared emitters to terahertz optics for physical security and environmental sensing. In particular, the selection of suitable terahertz systems has become more important in recent years because the previously often cited “terahertz gap” no longer exists.

In industrial use, systems such as Terahertz TDS (Time Domain Spectroscopy) and FMCW radars (Frequency Modulated Continuous Wave) are fundamental. The use of short-pulse lasers enables precise time measurements and spectroscopic investigations. In comparison, FMCW radars are smaller, cheaper and offer higher measurement rates, although their depth resolution is lower.

Additional techniques such as cross-correlation spectroscopy and optical FMCW are currently being tested and could soon become industrial-ready. The selection of the most suitable method always takes place in the context of the specific application, which underlines the flexibility of THz technology. The new research results could also enable high-throughput material screening and thus advance the development of more efficient THz technologies.