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!
Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State
What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy