New Way to Control Particle Motions on 2-D Materials

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Chip-scale isolation

With such a system, Kumar says, it should be possible “to do chip-scale optical isolation without the need for a magnetic field.” To achieve the same degree of optical isolation that this system would provide with a beam of light, Kumar says, with a conventional system would require a magnetic field with a strength of 7 tesla — a very strong field that would require a special research facility. (By comparison, the Earth’s magnetic field measures just 32 millionths of a tesla).

Theoretically, this could lead to applications such as new types of memory devices where information could be both written and read by using beams of polarized light, making them relatively immune to electromagnetic or other kinds of interference, the researchers say.

“The concept presented in this paper is very interesting and exciting,” says Fengnian Xia, an assistant professor of engineering and science at Yale University, who was not involved in this work. He adds, “In the long run, it may be possible to construct an electrically tunable on-chip isolator based on this concept, which can be a very critical component in integrated optics.”

In addition to Fang and Kumar, the team included Andrei Nemilentsau and George Hanson at the University of Wisconsin at Madison, Kin Hung Fung at Hong Kong Polytechnic University, and Tony Low at the University of Minnesota. The work was supported by the National Science Foundation and the Air Force Office of Scientific Research.