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A team of scientists at Simon Fraser University's Quantum Technology Lab and leading Canada-based quantum company Photonic Inc. have created a new type of silicon-based quantum device controlled both optically and electrically, marking the latest breakthrough in the global quantum computing race.

The research, in the journal Nature Photonics, reveals new diode nanocavity devices for electrical control over silicon color center qubits.

The devices have achieved the first-ever demonstration of an electrically-injected single-photon source in silicon. The breakthrough clears another hurdle toward building a quantum computer—which has enormous potential to provide computing power well beyond that of today's supercomputers and advance fields like chemistry, materials science, medicine and cybersecurity.

"Previously, we controlled these qubits, called T centers, optically (with lasers)," says Daniel Higginbottom, assistant professor of physics. "Now we're introducing electrical control as well, which increases the device capability and is a step toward applications in a scalable quantum computer."

According to Ph.D. candidate Michael Dobinson, the lead author of the study, the breakthrough will allow the research team to explore the different applications of the devices and the feasibility of scaling them up in larger quantum processors.

"This first demonstration shows that we can fabricate devices which allow for simultaneous optical and electrical control of T centers. This is exciting as it opens the door to many applications in quantum computing and networking," says Dobinson. "Overall, the optical and electrical operation combined with the silicon platform makes this a very scalable and broadly applicable device."

The SFU lab's leads, Stephanie Simmons and Mike Thewalt, co-founded Photonic Inc. to develop commercial-scale quantum computers and quantum networks. The company, which recently announced plans to establish a research and development facility in the U.K., was an integral partner in the latest study.

Christian Dangel, manager, quantum devices in the Integrated Photonics team at Photonic Inc. and a co-author of the manuscript says, "This project was a great opportunity to leverage Photonic's advanced fabrication capabilities and test their performance in next-generation devices in a research environment."

Researchers at the Silicon Quantum Technology Lab were among the first in the world to explore using silicon color centers for quantum technology.

Developing quantum technology using silicon provides opportunities to rapidly scale quantum computing. The global semiconductor industry is already able to inexpensively manufacture silicon computer chips at scale, with a staggering degree of precision. This technology forms the backbone of modern computing and networking, from smartphones to the world's most powerful supercomputers.

"Our colleagues Stephanie Simmons and Mike Thewalt first proposed silicon color centers as a platform for quantum computing at a time when very few people were thinking about them at all," says Higginbottom.

Now, national governments, including Canada through its National Quantum Strategy, major universities and corporations like IBM, Google and Microsoft are spending billions of dollars in a scramble to be first out of the gate with a scalable quantum computer.

Higginbottom says being at the forefront of the field has been a thrilling experience.

"It fits into this trajectory that we've been on. In 2020, SFU first introduced silicon T centers for quantum applications. In 2022, we integrated Single T centers with patterned nanophotonic devices," he says. "But those devices didn't have any interfaces or controls. Now we're controlling them optically and electronically. We're unlocking some of the capabilities that you need to build a useful computer out of these things."