Revolutionary terahertz spectrometer: a step forward in space observation
Researchers at Delft University of Technology (TU Delft), in close collaboration with SRON Netherlands Institute for Space Research and LongWave Photonics LLC, have achieved a breakthrough in terahertz spectroscopy—a vital technology to study galaxies, stars, and planetary formation. They created a centimeter-sized, lightweight terahertz spectrometer that could replace traditional half-meter-sized, bulky, and heavy spectrometers in future space observatories. The new device could significantly reduce costs and offer greater flexibility in launching, making these space observatories more affordable and feasible. The innovation is published in Laser & Photonics Reviews.
The universe’s history
The terahertz frequency range is crucial for unraveling the mysteries of the universe's history, providing insights into how galaxies and stars form and evolve, as well as how planets develop. Detecting the unique signals from molecules and atoms in this range requires advanced terahertz spectrometers. However, current technology faces significant limitations due to its size and complexity. Furthermore, these devices must be operated in space, as Earth's atmosphere absorbs terahertz signals, preventing observations from the ground.
Smaller and lighter device
To address these challenges, the team from TU Delft, SRON, and LongWave Photonics has demonstrated a groundbreaking concept for a centimeter-sized (1.1 cm) terahertz spectrometer, significantly reducing the size and weight compared to the traditional grating spectrometers. The spectrometer employs a cutting-edge metasurface, a specially patterned surface that manipulates electromagnetic waves. This surface enables it to achieve both the spreading and focusing of light.
A step forward
“Our design marks a step forward in space-based terahertz observations,” says Wenye Ji, the first author of the paper. “By combining the metasurface with an array of quantum cascade lasers, we were able to quickly demonstrate a novel spectrometer concept with high resolution.” Ji, a PhD candidate at Department of Imaging Physics of TU Delft, is supervised by Jian-Rong Gao, Paul Urbach, and Aurèle Adam.
The research team's spectrometer operates in the 1.85 to 2.4 terahertz range and demonstrated a spectral resolution of 270 with the help of a data analysis method. The spectral resolution reflects the capability to distinguish fine details in the signals it captures. As this is the first experimental demonstration, further optimisation is required to match the spectral resolution as expected from grating spectrometers.
Space exploration
The development of this compact and efficient terahertz spectrometer has far-reaching implications, from deepening our understanding of the universe to advancing space exploration technology. The team's work not only addresses current limitations but also provides a blueprint for future spectroscopic instruments used in space observatories.
This new spectrometer could be the key to unlocking more information about our galaxy and beyond, offering scientists a powerful tool to further investigate the fundamental processes behind star and planet formation.
