Gentry explores how SRI research is pushing the envelope of photonics, optics, and quantum technologies.
As a principal research scientist in SRI’s Applied Physics Laboratory, Cale Gentry spends most of his time working at the bleeding edge of next-generation technologies like quantum communications, photonic circuits, and atomic sensing.
At this micro-scale, our ability to measure and manipulate physical reality at and even below the atomic level is delivering astonishing new discoveries and capabilities.
Here, Gentry explains why he and his team are so excited about the possibilities of quantum, photonics, and related technologies.
Your group at SRI is working on some very cutting-edge technologies. Can you start by explaining the sort of expertise that your team brings to the table?
My background and PhD training is primarily in component-level integrated photonics for quantum systems and optical beam steerers. In my seven years at SRI, we have focused strongly on systems innovations that choose the right photonic technology for the particular application, whether those are photonic integrated circuits or more conventional fiber or free-space components. My team works a lot on photonic solutions to emerging challenges in areas like sensors, optical communications, microwave signal processing, and quantum interconnects and networks.
“In optical communications, a lot of the focus is on creating tiny communication devices that require very little energy, which is critical for both next-generation drones and secure space communications.” — Cale Gentry
I lead a small group of very like-minded individuals with backgrounds that range from photonic integrated circuit engineering to stable laser development to quantum repeater research.
What are some of the practical implications of that work?
On the surface, our projects can sound a bit abstract. For example, steering an optical beam in two dimensions just by applying electrical signals to the chip without using any mechanical motion. That compact device can apply to a large range of applications, one of which is optical communication. Why is that important? In optical communications, a lot of the focus is on creating tiny communication devices that require very little energy, which is critical for both next-generation drones and secure space communications. There are implications for defense, for sure, but also for commercial communications technologies.
Or say we’re using optical beams to interact with atomic vapors or levitate micrometer-sized glass spheres: What’s the point of doing that? Well, for one thing, extremely sensitive sensors.
We also have a very cool project that’s creating a sensor to detect the origin point of a laser beam, which has huge applications in areas like defense and commercial aviation. Laser strikes on airplanes are becoming more common every year and they do sometimes distract and even injure pilots. Right now, there’s literally no way to pinpoint where those beams are coming from. We think photonic integrated circuits can provide the answer.
Why is SRI the right place to pursue this kind of cutting-edge science and engineering?
When I was considering a role here, I learned that SRI had expertise in cutting-edge LiDAR systems going back to the 1960s. So I knew there was definitely a history of compelling work.
Also, I was excited that this was a place where there was an opportunity both to mature some low-TRL programs and build functional applications. A number of our current programs, for example, are funded by DARPA’s Microsystems Technology Office (MTO), which is one of the leaders in championing truly novel work in the areas where we are active. And then there’s the more applied side of things. We’re always pursuing opportunities to help customers take advantage of new discoveries in areas like photonic integrated circuits and optical systems. It’s a continuum that’s all about doing the fundamental research and then turning it into concrete solutions.
What excites you about the work SRI’s going to be pursuing in the next few years?
I think optical communications, especially for small platforms like drone and satellites, is incredibly interesting. We’ll be significant contributors to some exciting advancements there.
“Last year marked the 100th anniversary of quantum science; it’s incredible to realize that 100 years later, we’re just beginning to unlock the most exciting applications of quantum behavior.” — Cale Gentry
We’re also doing some really cool work in microwave communications and processing. We’ve been developing hybrid communications systems that involves both optics and microwave techniques to achieve orders of magnitude improvement over what can be done today.
And then, of course, there’s quantum. There has been significant interest in revolutionizing computing, networking, and sensing with quantum systems. And nearly all of the technological platforms and approaches utilize photonic technologies, which is SRI’s sweet spot.
For those of us who aren’t quantum experts: Why, fundamentally, is photonics innovation so important for quantum systems?
It gets complex pretty quicky, but here it goes: Often the ‘quantum-ness’ of a system will be entirely related to something like an individual atom or ion. But we need to use a non-quantum (i.e., classical) light beam to control or interrogate the quantum behavior of that particle. That’s how devices like atomic magnetometers and Rydberg sensors work. Here, our photonics expertise provides a path to scaling new capabilities as we find new ways to both manufacture and miniaturize photonics-based components for quantum systems.
There’s also quantum networking, which utilizes photons of light as “flying qubits” for transmitting quantum information at the speed of light with very little loss. This is something we are significantly involved in developing.
Last year marked the 100th anniversary of quantum science; it’s incredible to realize that 100 years later, we’re just beginning to unlock the most exciting applications of quantum behavior.
Learn how SRI is building the quantum future.
