A research team at INRS develops a simple, energy‑efficient method to isolate the right photons—along with their quantum properties.
In quantum technologies, everything depends on the ability to detect the properties carried by a single photon. But in the real world, that photon of interest is often buried in a sea of unwanted light — a true "needle in a haystack" challenge that currently limits the deployment of many applications, including secure quantum communication, quantum sensors used in telescope networks, as well as the interconnection of quantum computers to accelerate the development of new drugs and materials.
At the Institut national de la recherche scientifique (INRS), the team of Professor José Azaña , in collaboration with Professor Roberto Morandotti 's group, has developed a surprisingly simple and energy‑efficient way to overcome this obstacle. The work was carried out by Benjamin Crockett during his PhD at the INRS Énergie Matériaux Télécommunications Research Centre . He recently completed his degree and is now a Banting postdoctoral fellow at the University of British Columbia (UBC).
Their method not only reduces noise but, more importantly, recovers essential quantum properties that would otherwise be lost in bright environments where current technologies fail.
"With this new methodology, we were able to recover quantum states corrupted by large amounts of noise—states that would otherwise have been lost. This could allow quantum systems to operate under real‑world noise conditions, helping overcome one of the major barriers to the practical deployment of quantum technologies."
— Benjamin Crockett, lead author of the study and INRS graduate
The team's findings were published in Science Advances .
Recovering Hidden Quantum Information
By repurposing a classical optical device — the Talbot Array Illuminator (TAI) — the researchers succeeded in reorganizing light in time to highlight the useful photons without destructive amplification. The method works for individual photons as well as for time‑entangled photon pairs, a key resource for quantum communication. It can even reveal non‑classical quantum signatures that normally remain invisible in bright environments.
One of the study's key insights, explains Benjamin Crockett, is that we can manipulate quantum correlations between photons in much the same way we process images.
Imagine you have an image corrupted by noise (as shown in A of the figure). To make it readable, you can pass it through a series of lenses. These lenses redistribute the image: instead of a blurry, noisy picture, it becomes a set of bright, well‑defined points. This transformation makes it easier to ignore the noise and extract the meaningful information.
This principle can be applied in time as well.
Just as we process a spatial image with optical elements, we can use a temporal equivalent of this imaging system to reorganize photon correlations over time. The correlations are redistributed into a series of distinct temporal points, making them much easier to analyze despite noise.
"Seeing quantum properties emerge in a bright environment, without complex processing steps, was one of the most striking results."
— José Azaña, Professor at INRS who specializes in ultrafast photonics
Next Steps
The next phase for the team at INRS is to integrate this method directly onto a chip, to test it in optical fibers and free‑space channels, and to combine it with other techniques to improve the range and reliability of future quantum links.
This work was made possible thanks to funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Fonds de recherche du Québec – Nature et technologies (FRQNT).
Benjamin Crockett distinguished himself at INRS with several major international honors. He became the first scientist from a Canadian university to win the Tingye Li Innovation Award at the OFC conference, a key milestone in optics and communications. He also received SPIE's top distinction, the D.J. Lovell Scholarship, along with additional recognition from Optica and the IEEE Photonics Society, underscoring the impact of his work in quantum technologies.
