Yale study details potential of 'anti-laser'

Researchers have developed a system that could lead to breakthroughs in local area networks and photonics by directing light and electromagnetic waves for signal processing without unwanted signal reflections, according to a new study.

According to a report by Yale University's School of Engineering & Applied Sciences, A. Douglas Stone of Yale previously led a team in the creation of an "anti-laser," or "coherent perfect absorber." Instead of emitting a beam as a laser does, an anti-laser absorbs input light with the same precision. The system builds off the “anti-laser,” the report stated.

In the new study, researchers built off this concept and developed a device based on reflectionless scattering modes, which redirect waves to specific channels instead of absorbing them. 

“We asked if there is some principle like this where we can guide light instead of transducing it into another form of energy,” said Stone, the Carl A. Morse Professor of applied physics and physics. “Because with optical fibers and modern photonic circuits, guiding light and not having any of it reflect back is extremely valuable.”

Stone worked on the theoretical side of the project, while Philipp del Hougne of the University of Rennes in France built the device.

The report, published by Scientific Advances, said the breakthrough could lead to significant advancements in reducing power consumption in cell phone networks and eliminate unwanted signal reflections. 

In addition to Stone and del Hougne, the study's other authors are Ali Alhulaymi, a Ph.D. student at Yale, and Jérôme Sol of the University of Rennes.

“Instead of having it all transduced, it could either all go into our chosen output channels or some of it could be absorbed and the rest go into the output channels,” Stone said. “In the next step, we want to make a similar device where the absorption is negligible, so that all of the energy is efficiently routed to perform its information or sensing function. 

"There is great interest in such technologies to reduce the power consumption of cell phone networks, for example,” he added.