< Photon Queue is a participant in Cohort 4 of Duality >
The proliferation of quantum computers comes with a need for new memory and data storage technologies – a clear market need for which Photon Queue was conceptualized to address.
The startup, a participant in Cohort 4 of Duality, was founded based on work out of the lab of Paul Kwiat, a physics professor at the University of Illinois Urbana-Champaign. The team seeks to address the problem of efficiently storing single photons to enable various quantum applications in the near-term.
“Almost every existing quantum memory technology can be categorized as a ‘matter-based’ memory, which rely on the transduction of photonic qubits into a state of matter for storage. This transduction approach, while often offering impressively long storage times, can suffer from many performance drawbacks that are hard to overcome,” explained Photon Queue CEO Nathan Arnold, who has spent his PhD thus far under the guidance of Kwiat, researching and developing the core technology.
The startup’s unique approach avoids this transduction process and the related challenges by storing photons in free-space storage loops. “We simply use an optical switch paired with high-reflectivity mirrors to store photons for relatively long durations in a compact free-space format,” said Arnold, noting that “the simplest solution to a problem is often one of the best solutions.”
And this is why Photon Queue’s technology works so well, he explained – and also why competing memory technologies, while “more interesting” from the viewpoint of a physicist, suffer from relatively low efficiency and bandwidth, making it difficult to realize any quantum advantage.
Free-space operation enables Photon Queue to use bulk optics that work well for a range of applications. Additionally, the technology doesn’t require costly cryogenics, ovens, or vacuums, and can be designed to work with virtually any source of single photons.
“Overall, our products exhibit high enough performance to be used immediately with many systems, enabling researchers to focus on solving other problems,” Arnold said.
The startup’s first prototype includes only a single short-duration storage loop, which though useful for some photon-synchronization applications, is relatively limited in its utility. To expand its ability to be used in more scenarios, future devices will include additional storage loops with longer base storage times.
As Arnold explained, “Doing so will make our technology more useful for the same photon-synchronization applications as our single-loop prototype, while also providing efficient storage for more demanding applications such as entanglement swapping across quantum network nodes.”
Longer base storage times are achieved by placing a highly efficient and compact reflection cavity inside the loop. These reflection cavities, also are useful as a standalone product for both classical and quantum applications.
“Many of our target customers don’t need the configurable storage time provided by our loop-based memory, but rather only need to efficiently store photons for a fixed time,” Arnold said. “Traditionally customers would just use a fiberoptic cable to achieve a single fixed delay, but fibers have intrinsic attenuation of light that is difficult to reduce. If maximum efficiency is a priority, then the limitations of optical fiber are quite significant.”
Looking ahead to the next few years, Photon Queue plans to develop a cavity-based storage system that beats fiberoptic cables in end-to-end efficiency for a fixed delay time. And they have already garnered interest from academic, government, and industrial players in quantum.
“A lot of our efforts in trying to commercialize this technology came about because these external parties have continuously asked us when it would be available for them to buy,” said Arnold. “We have been extremely fortunate to have a technology that others have immediately wanted and now it’s a matter of building the company and getting it into their hands.”
As part of this, Duality will provide the opportunity for the team for the team to focus on developing Photon Queue and its products.
“By making use of the extensive resources offered to me I hope to develop personally as a researcher and leader. I hope to leverage the incredible local network of quantum enthusiasts to meet new customers, make our products useful to more people, and tap into the strong quantum workforce,” said Arnold. “Photon Queue grew its roots at the University of Illinois Urbana-Champaign, so we are excited to further cement our position in the incredible quantum ecosystem in Illinois as a whole, and more specifically in Chicago.”
The startup’s team also includes other graduate students in the Kwiat Quantum Information Group, Colin Lualdi and Kelsey Oritz, and postdoctoral researcher Kai Shinbrough.
Lualdi brings with him experimental experience in applying the technology to various scenarios, and Ortiz, who joined the team after they received early funding for product development, skills in designing a practical quantum payload.
Shinbrough, who spent his PhD work on a competing memory technology, provides valuable perspectives on matter-based memories – and recognized the utility and high performance of the memory technology that has been developed in the Kwiat lab compared to other existing systems. An undergraduate, Will Shen, also has been brought on to help model and build the first prototype.
// Read more about the other startups in Duality Cohort 4: