Developments in Optical Waves Could Lead to New Lasers
By LIDA TUNESI
Optical waves—light waves with frequencies near those of visible light—are hard to contain. This presents challenges for engineers designing an optical device, such as a laser or telescope. In today’s technologies, waves are usually contained by mechanisms called resonators.
Now, researchers have developed a new way to trap and release optical waves on demand, using a special type of material. Their advances will help researchers dynamically control optical signals, potentially leading to the development of a new class of lasers.
The innovation comes from the labs of Andrea Alù, director of the Photonics Initiative at the Advanced Science Research Center at The Graduate Center, CUNY, and Professor Alexander Khanikaev, a professor in the electrical engineering and physics departments at The City College of New York, who is also affiliated with the CUNY ASRC. The research was published in Nature Photonics.
This new method uses topological metamaterials to control the light waves. Topological materials are very robust—even when they have defects, such as from manufacturing or wear and tear in harsh environments, they can maintain their special properties. Because of this, researchers predict these materials will have a big effect on technologies in fields from acoustics to quantum electronics. Meanwhile, metamaterials are synthetic materials that let researchers do things they can’t do with natural materials, such as mimicking quantum phenomena and giving very precise control over waves.
Bringing all these ideas together, the researchers found a way to trap optical waves using a topological metamaterial that uses a pattern called a kagome lattice. The term kagome derives from a Japanese weaving pattern of overlapping triangles.
“Our work offers a new way of implementing confinement in any number of dimensions,” Khanikaev said, “whether for guiding waves or for trapping them in a fixed location.”