Jul 9 2019
A team of scientists at the UCLA Samueli School of Engineering has designed a new, ultra-sensitive light-detecting system that can allow astronomers to view stars, galaxies, and planetary systems in excellent detail.
Ning Wang, the study’s lead author, and Professor Mona Jarrahi working on the terahertz detector setup. (Image credit: UCLA)
The sensor system operates at room temperature, which is an enhancement over analogous technology that only functions in temperatures close to –454 ºF or 270 º below zero Celsius. A paper describing this development has been recently reported in Nature Astronomy.
The innovative system is capable of detecting radiation in the terahertz band of the electromagnetic spectrum, which contains parts of the microwave and far-infrared frequencies.
The sensor system creates images in excellent clarity, and it can also identify terahertz waves across a wide spectral range—a phenomenal improvement that is at least 10 times more than existing technologies that only sense terahertz waves in a narrow spectral range.
The extensive capabilities of the new system could enable it to do observations that presently need a number of different instruments. It recognizes what kinds of molecules and elements—for instance, organic molecules such as including carbon monoxide, oxygen, and water—are present in those areas of space by observing whether their separate obvious spectral signatures are present.
Looking in terahertz frequencies allows us to see details that we can’t see in other parts of the spectrum. In astronomy, the advantage of the terahertz range is that, unlike infrared and visible light, terahertz waves are not obscured by interstellar gas and dust that surround these astronomical structures.
Mona Jarrahi, Professor, Department of Electrical and Computer Engineering, UCLA
Jarrahi led the latest study. The novel technology can be particularly effective in space-based observatories, because terahertz waves can be sensed without any atmospheric interference, unlike on Earth, Jarrahi added.
The system can assist researchers to gain a deeper understanding of the composition of astronomical structures and objects and also get new insights into the physics of how they originate and die.
In addition, the system can help answer queries about the way they communicate with the radiation, gases, and dust existing between galaxies and stars, and it can also provide clues about the cosmic origins of organic molecules or water that could denote whether a planet is favorable to life or not.
Furthermore, the sensor system can be utilized on Earth to identify toxic gases for environmental monitoring or security purposes. The key to the latest sensor system is how it changes the incoming terahertz signals into radio waves, which can be managed easily. Normally, terahertz signals cannot be easily detected and analyzed with average scientific instruments.
Superconducting materials are used by current systems to convert terahertz signals into radio waves. However, in order to work, such systems utilize a unique liquid coolant to maintain those materials at very low temperatures, close to absolute zero.
From a practical standpoint, the equipment can be supercooled on Earth. However, when the sensors are carried on spacecraft, the amount of coolant aboard the spacecraft tends to reduce their lifespans In addition, since the weight of the spacecraft is very significant, it can be difficult to carry the additional pounds of coolant required by the equipment.
To address the coolant and the associated weight problems, the UCLA scientists came up with a novel technology. The new device utilizes a light beam to interact with the terahertz signals within a semiconductor material with metallic nanostructures. Following this, the system changes the incoming terahertz signal into radio waves, which are subsequently read by the system and can be figured out by astrophysicists.
The lead authors of the study are Semih Cakmakyapan, a former postdoctoral scholar at UCLA, and Ning Wang, who received a doctorate from UCLA, both of whom were members of Jarrahi’s research team. UCLA graduate student Yen-Ju Lin and Hamid Javadi, a scientist at the NASA Jet Propulsion Laboratory are other authors of the study.
JPL’s Strategic University Research Partnership program, the U.S. Department of Energy, the National Science Foundation, and the Office of Naval Research supported the study.