A step closer to making terahertz technology usable in the real world

Terahertz is a form of electromagnetic radiation that exists between the microwave and infrared range. THz radiation connects photonic and electrical devices and provides various untapped bandwidths. The absence of sources and detectors, as well as a perceived lack of necessity, have historically led to a lack of THz activity. This makes terahertz technology less widely used.

A group of scientists from the Cavendish Laboratory and colleagues from the Universities of Augsburg (Germany) and Lancaster (England) found a novel phenomenon in 2D conductive systems that promises increased terahertz detector performance. When two-dimensional electron systems are subjected to terahertz vibrations, they discovered a novel physical effect.

“We were developing a new type of terahertz detector, but when measuring its performance, it turned out that it showed a much stronger signal than should be theoretically expected. So we came up with a new explanation,” stated Dr. Wladislaw Michailow, Junior Research Fellow at Trinity College Cambridge. "So we came up with a new explanation.”

“This explanation lies in how light interacts with matter,” scientists explain.At higher frequencies, matter absorbs photons. The photoelectric effect was described using this interpretation, which was the cornerstone of quantum mechanics. Our smartphones' cameras detect light via quantum photoexcitation, and solar cells use it to create power from light.

In the photoelectric effect, incoming photons cause electrons to be liberated from conductive materials. Photons in the ultraviolet or X-ray range can eject electrons into a vacuum in a 3D semiconductor, or photons in the mid-infrared to visible range can discharge electrons into a dielectric.

The discovery of a quantum photoexcitation mechanism in the terahertz band that is analogous to the photoelectric effect is the novelty.

“The fact that such effects can exist within highly conductive, two-dimensional electron gases at much lower frequencies has not been understood so far, but we have been able to prove this experimentally," Wladyslaw added.

Scientists named their phenomenon an “in-plane photoelectric effect.”  They discussed various advantages of using this phenomenon for terahertz detection in their research. The size of the photoresponse created by incoming terahertz radiation by the "in-plane photoelectric effect" is substantially larger than predicted from other methods previously known to produce a terahertz photoresponse. 

According to experts, this phenomenon will allow the development of terahertz detectors with substantially higher sensitivity. The discovery brings terahertz technology one step closer to becoming practical in the real world, according to specialists,