Physicists have long known about the existence of unique points where two physical states coalesce into one. They call them “exceptional points.”
These points give rise to counterintuitive phenomena; a more opaque material can seem more transparent, and light may be allowed to propagate in one direction but not the other.
Now, in a paper published in the journal Nature, scientists have outlined a new concept called the “exceptional ring.”
An exceptional ring is a continuous ring of exceptional points, and its discovery opens new avenues of research for basic science and technology, note the researchers. In this case, the exceptional rings were found in a slab of nanostructured material called a photonic crystal.
The researchers found that exceptional rings arise from Dirac cones, which commonly occur in a 2D material and have been the focus of many important physics discoveries in the past decade.
“This finding may enable a number of exciting applications,” says co-lead author Chia Wei Hsu, a Yale University postdoctoral researcher in applied physics. “Examples include more sensitive biological and chemical sensors, lasers with higher output power, and light-emitting devices with directional emission.”
The other co-lead authors of the research are Bo Zhen of MIT and Yuichi Igarashi of Smart Energy Research Laboratories in Japan.
Source: Yale University