The first completely integrated parity-time symmetric electronic system has been built by researchers from the labs of Lan Yang, the Edwin H. & Florence G. Skinner Professor, and Xuan “Silvia” Zhang, associate professor, at Washington University in St. Louis’s McKelvey School of Engineering.
It can also be manufactured without the use of unusual materials, using simply the same basic microelectronic fabrication process that is now employed for regular integrated circuits.
The findings were published in the journal Nature Nanotechnology on March 17th.
Energy flow in PT-symmetric systems can be altered in unexpected ways. They can currently only operate in a narrow frequency range, either in the extremely low-frequency acoustic domain or in the extremely high-frequency optical domain.
This innovative technique included in an integrated circuit an idea with outstanding mathematical features derived from quantum physics. It opens up a new region of the spectrum for research in the gigahertz to terahertz range.
“Our work opens this intermediate region (of the spectrum) that encompasses critical microwave and millimeter wave applications; we bridge the gap,” Zhang explained.
“No one on the planet has ever built PT-symmetric systems that cover this frequency range.”
The capacity to perfectly balance the energy loss of one resonator with the gain of another connected resonator is critical in these systems. This unique point of equilibrium is known as PT symmetry, and it enables novel and powerful techniques to manipulate the flow and localization of energy.
A mirror image undergoes parity transformation, which means that a right hand is reversed and becomes a left hand, and vice versa. Time reversal in a video is an example of time reversal—the events in the film move backward in time.
If both transformations are performed at the same time and “cancel each other out,” leaving the system unchanged, the system is said to exhibit PT symmetry.
In coupled photonic resonator systems, such a concept has been used to develop new tactics for controlling light flow, such as nonreciprocal light transmission.
The ability to manage a larger portion of the electromagnetic spectrum opens the door to new discoveries and technologies, according to Weidong Cao, a postdoctoral research associate in Zhang’s team.
In practice, these systems are critical components of radar, wireless communications, and power-transfer systems. At the moment, the necessary parts necessitate massive, magnetic cores. However, “we can now compress them down to the size of a fingernail,” Zhang explained.
The system is scalable due to a revolutionary fabrication process, making it easier to take advantage of new capabilities in existing technologies.
“Integrated circuit fabrication and our circuit design allow you to build specifically for different areas of the electromagnetic spectrum,”
Cao said
“Our circuit design and integrated circuit fabrication enable you to create, especially for different sections of the electromagnetic spectrum,” Cao explained.
“Our findings show that incorporating PT symmetry into integrated circuit technology could benefit a wide range of chip-based applications such as frequency modulation and microwave propagation manipulation.”
Yang is amazed by physics’s potential to have such a large and immediate impact on technology.
“It’s fantastic to show the improved performance and functionality provided by a novel design informed by fundamental research on an industry-wide platform,” she said.
