The February 2023 issue of IEEE Spectrum is here!

Close bar

Nanowire Circuit Guides Both Electricity and Light on the Same Wire

Nanoscale light-matter interaction observed in circuit could lead to on-chip optical processing

1 min read
Nanowire Circuit Guides Both Electricity and Light on the Same Wire
Illustration: Michael Osadciw/University of Rochester

The field of plasmonics—the use surface plasmons generated when photons hit a metal structure—might enable photonic circuits that could do what electronic ICs do, but do it much faster—at the speed of light.  Without plasmonics, photonic circuits would be too large, because they need to accommodate wavelength of light.

In a step toward that goal, a joint research team from the University of Rochester and the Swiss Federal Institute of Technology in Zurich have developed a primitive circuit consisting of a silver nanowire and single-layer flake of molybdenum disulfide (MoS2). This simple circuit can efficiently guide both electricity and light along the same wire.

In the experiment, which was published in the journal Optica, a laser was used to trigger the plasmons on the surface of the wire. The plasmons coming off the nanowire triggered a photoluminescence in the MoS2, which is a two-dimensional material like graphene but has an inherent band gap. Excitons—basically energized electrons bound to positively charged holes that form when light hits a semiconductor—form in the MoS2, and decay into the nanowire plasmons. So, the international team demonstrated that the nanowire serves the dual purpose of exciting the MoS2 via plasmons and recollecting the decaying exciton as nanowire plasmons.

“We have found that there is pronounced nanoscale light-matter interaction between plasmons and atomically thin material that can be exploited for nanophotonic integrated circuits,” said Nick Vamivakas, assistant professor at the University of Rochester, in the press release.

The combination of subwavelength light guidiance and strong nanoscale light-matter interaction they demonstrated could help lead to compact and efficient on-chip optical processing, the researchers believe.

The next step in their research will be to demonstrate the primitive circuit with light emitting diodes.

The Conversation (0)

Two Startups Are Bringing Fiber to the Processor

Avicena’s blue microLEDs are the dark horse in a race with Ayar Labs’ laser-based system

5 min read
Diffuse blue light shines from a patterned surface through a ring. A blue cable leads away from it.

Avicena’s microLED chiplets could one day link all the CPUs in a computer cluster together.

Avicena

If a CPU in Seoul sends a byte of data to a processor in Prague, the information covers most of the distance as light, zipping along with no resistance. But put both those processors on the same motherboard, and they’ll need to communicate over energy-sapping copper, which slow the communication speeds possible within computers. Two Silicon Valley startups, Avicena and Ayar Labs, are doing something about that longstanding limit. If they succeed in their attempts to finally bring optical fiber all the way to the processor, it might not just accelerate computing—it might also remake it.

Both companies are developing fiber-connected chiplets, small chips meant to share a high-bandwidth connection with CPUs and other data-hungry silicon in a shared package. They are each ramping up production in 2023, though it may be a couple of years before we see a computer on the market with either product.

Keep Reading ↓Show less