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A New Way to Control Light Transmission May Improve Electronics

Illustration of isolator

Researchers at the Advanced Science Research Center (ASRC) at The Graduate Center, CUNY and the University of Texas at Austin have developed a new way to send a light wave in only one direction instead of two, opposite directions. This type of transmission breaks a physics principle known as reciprocity. Their findings appear in Nature Electronics.

Reciprocity requires electromagnetic signals to be identical in opposite directions, which can cause problems in equipment like lasers and circuits. While devices called isolators remedy the situation by forcing the signal to move in only one direction, they pose challenges.

Some isolators use magnetic fields to do this, but the magnets can be large, heavy, and expensive. Isolators that don’t use magnets generally perform less well.

In their new study, the researchers present a new microwave isolation method that does not use magnets and yet achieves good transmission, and at broad bandwidths. The research could impact the design of consumer electronics, surgical lasers, and automotive radar and lidar systems, the team says.

“We have been working on overcoming reciprocity without magnets for a few years,” said Professor Andrea Alù, director of the ASRC’s Photonics Initiative and lead author of the study. “In this paper, we show that a non-magnetic device free of an external power source — thanks to suitably tailored nonlinearities — can dramatically break transmission symmetry and realize efficient broadband isolation.”

The researchers plan to continue work on the isolator and fine-tune its functionality.

Beyond SUM

Explore This Work
Broadband passive isolators based on coupled nonlinear resonances
Nature Electronics, 2018

Work By
Andrea Alù (Professor, Physics) | Profile 1 | Profile 2

Colleges and Schools
The Graduate Center

Bonus Content
Scientists Realize Breakthrough in Controlling the Transmission of Light (ASRC News)

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