Studying light, in the City of Light

For Patrick Cameron, born and raised in Aboyne, a village in the northeast of Scotland, science has been a lifelong interest. “My dad would find me books about science when I was a kid, and I enjoyed it at school,” he says. “When it was time to choose what to study at university, I didn't see myself doing anything else apart from physics.” By the time Cameron was considering a final-year university project, he was drawn to the practicalities of photonics-focused physics: “I quite like this idea that you can have your bench and engineer your experiment and build it yourself.”

Cameron’s BSc in physics in 2019 was followed by an MSc in quantum technology in 2020, both at the University of Glasgow. During that master’s year, he discovered Daniele Faccio’s Extreme Light Group and worked under the supervision of group member Hugo Defienne. After becoming interested in Faccio and Defienne’s research into quantum imaging, Cameron was accepted as a PhD student on a project to explore ways of manipulating and shaping quantum light for imaging applications. And, when Defienne recently moved to Paris to establish his own lab, Cameron’s options included working with Defienne across the Channel.

Cameron is pursuing this opportunity thanks to a recent collaboration between SPIE and the University of Glasgow. Established in 2020, the SPIE Early Career Researcher Accelerator Fund in Quantum Photonics, part of the SPIE Endowment Matching Program, was created by SPIE and the university with an initial funding of $1 million to support graduate students working in quantum photonics. It encompasses two new programs at Glasgow: the SPIE Early Career Researcher in Quantum Photonics Scholarship, and the SPIE Global Early Career Research program. The latter supports international cross-laboratory collaborations between leading quantum-photonics research groups, pairing university early-career researchers with counterparts from external laboratories for six-month-long shared projects. This year, Cameron, as the first beneficiary of the cross-laboratory program, has discovered his niche — for now.

“I’m studying the propagation of entangled light through complex media, specifically multimode optical fibers,” says Cameron. “I chose to do this project in Paris because of Dr. Defienne’s expertise and the reach of his professional network: aside from his own laboratory, he’s closely aligned with Sylvain Gigan’s group.” The research interests of Gigan, a professor of physics at the Sorbonne and a researcher within the Laboratoire Kastler-Brossel, include fundamental investigations of light propagation in complex media, biomedical imaging, sensing, and signal processing, as well as quantum optics and quantum informations in complex media. “This is just a great opportunity for me to meet other students and researchers who are doing similar and adjacent things to what I do,” notes Cameron. “It’s an excellent way to develop my technical skills as well as my own network.” He appreciates, too, having shared access to an immediate shorthand in terms of conversations with colleagues.

“It’s really great to be able to work closely with people who are working with the same concepts,” he points out. “You can ask people about your ideas without having to explain the whole thing from scratch; because they are already familiar with what you’re doing, you can get right to the point. I have access to a lot more people who know what they’re doing, who have a range of expertise and knowledge, and a different point of view on things.” He grins. “Yeah, I can pester a lot more people.”

Cameron finds the rapidly growing field of quantum optics “very cool, and very weird,” and, above all, fascinating as a research and engineering topic. “Quantum underlies everything,” he says. “In one way, it’s hiding in the background, but it enables so much. Especially with optics and optical imaging, there are more degrees of information that you’re accessing.”

Though he can’t predict what real-life outcomes might come of his work — “there are a lot of different people going in a lot of different directions at the same time to see what works” — one interesting aspect of quantum imaging focuses on microscopy, though the technology is still catching up with the frontiers of exploration. “The technology needed for clean images for diagnostics, for example, that technology is quite advanced and complicated,” says Cameron, “especially when it comes to the cameras: you need cameras that are sensitive enough to detect single photons. Right now, we use one kind of camera, SPAD — single photon avalanche diodes — that are a type of detector, and we also work with EMCCD cameras which are electron-multiplying charge-coupled devices. At the moment, there are quite a lot of options for these single-photon sensitive cameras; just 10 or 15 years ago, that just wasn’t the case. I think that is partly what’s led to the expansion of quantum imaging in general and why a lot more people are doing it, because the technology’s catching up with the concepts.”

And that coalescence is part of what makes the combination of quantum and light the latest frontier. “We’re just getting to the point where technology is good enough to actually make applications that exploit the quantum properties of whatever you’re engineering. And light is great to work with: it’s not that difficult, and we have lots of solid technology to work with, like lenses and cameras. I mean, we do need increasingly fancy cameras, but there’s a lot of research and engineering development that’s already gone into how to utilize light and communicate with light and apply it to, say, real-world quantum communications and computing, so it seems like it makes sense to exploit this work that’s already been done.”

While he’d like to pursue a post-doc, Cameron is also considering a career beyond academia. One option might be working with a startup company that makes the cameras or that makes the sources for camera elements, but opportunities that hew closer to non-quantum physics or optics would also work. “There are a lot of transferrable skills in optics,” he says, “so it’s all very promising.”