Engineers at the University of California, San Diego have demonstrated a new and more efficient way to trap light, using a phenomenon called bound states in the continuum (BIC) that was first proposed in the early days of quantum wave mechanics.
Boubacar Kanté, an assistant professor in electrical and computer engineering at UC San Diego Jacobs School of Engineering, and his postdoctoral researcher Thomas Lepetit described their BIC experiment online in the rapid communication section of journal Physical Review B.
The study directly addresses one of the major challenges currently facing nanophotonics, as researchers look for ways to trap and use light for optical computing circuits and other devices such as tiny switches.
“The goal in the future is to make a computer that performs all kinds of operations using light, not electronics, because electronic circuits are relatively slow. We expect that an optical computer would be faster by three to four orders of magnitude.” Kanté said. “But to do this, we have to be able to stop light and store it in some kind of cavity for an extensive amount of time.”
To slow down and eventually localize light, researchers rely on cavities that trap light in the same way that sound is trapped in a cave. Waves continuously bounce off the walls of the cavity and only manage to escape after finding the narrow passage out. However, most current cavities are quite leaky, and have not one but multiple ways out. A cavity’s capacity to retain light is measured by the quality factor Q—the higher the Q, the less leaky the cavity.
Lepetit and Kanté sought a way around the leak problem by designing a metamaterials BIC device consisting of a rectangular metal waveguide and ceramic light scatterer. Instead of limiting the size and number of passages where light can escape the cavity, the cavity’s design produces destructive interferences for the light waves. Light is allowed to escape, but the multiple waves that do so through the different passages end up cancelling each other.
“In a nutshell, BICs can enhance your high-Q,” the researchers joked.
Other researchers have worked on ways to trap light with BIC, but the cavities have been constructed out of things like photonic crystals, which are relatively large and designed to scale to the same wavelength as light. The device tested by the UC San Diego researchers marks the first time BIC has been observed in metamaterials, and contains even smaller cavities, Kanté said.
The difference is important, he explains, “because if you want to make compact photonic devices in the future, you need to be able to store light in this subwavelength system.”
Moreover, earlier researchers had reported observing only one BIC within their systems. Lepetit and Kanté observed multiple bound states in their system, which make the light trap more robust and less vulnerable to outside disruptions.
The researchers say trapping light via BIC will likely have a variety of other applications beyond circuitry and data storage. Since the system can hold light for an extended time, it may enhance certain nonlinear interactions between light and matter. These types of interactions can be important in applications such as biosensors that screen small molecules, or compact solar cells.
The publication is “Controlling multipolar radiation with symmetries for electromagnetic bound states in the continuum,” published 1 December in the Rapid Communications section of Physical Review B.
This research is funded in part by a grant from the Qualcomm Institute at the University of California, San Diego via the institute’s Calit2 Strategic Research Opportunities (CSRO) program.
Jacobs School of Engineering
firstname.lastname@example.org Ioana Patringenaru
Jacobs School of Engineering
Daniel Kane | EurekAlert!
Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters
Light-driven atomic rotations excite magnetic waves
24.10.2016 | Max-Planck-Institut für Struktur und Dynamik der Materie
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering