What if we could control one of nature’s most fundamental processes with the twist of a light beam?
That’s exactly what a team of researchers from the University of Ottawa has done. In a groundbreaking study, they’ve discovered how to control the ionization of atoms and molecules—an essential process at the heart of everything from lightning bolts to medical imaging technologies. Their findings, published in Nature Communications under the title “Orbital angular momentum control of strong-field ionization in atoms and molecules,” could spark major advances in fields as diverse as X-ray generation, plasma physics, and even quantum computing.
What Is Ionization and Why Does It Matter?
To appreciate the significance of this discovery, let’s take a moment to understand ionization. At its core, ionization happens when an atom or molecule loses an electron and becomes a charged particle—or an ion. It’s a natural phenomenon, occurring in events like auroras dancing across the night sky, strikes of lightning, and even inside your television screen if you have an old-school plasma TV.
But ionization isn’t just a curiosity of nature. It’s a process that powers some of today’s most important technologies: plasma reactors, particle accelerators, X-ray machines, and more. Despite its importance, scientists have long believed that they could only control ionization in limited ways. Once you exposed an atom to a strong enough electric field—like that from an intense laser—it would shed its electrons. But exactly how it did so seemed out of our hands.
That’s the long-held belief a University of Ottawa team has now flipped on its head.
A Team with a Vision: Who’s Behind the Breakthrough?
The discovery is the result of a collaboration led by Professor Ravi Bhardwaj, a Full Professor in uOttawa’s Department of Physics, alongside Ph.D. student Jean-Luc Begin. They worked with some of the biggest names in physics: Professors Ebrahim Karimi, Paul Corkum, and Thomas Brabec. Together, they combined expertise in ultrafast lasers, quantum optics, and theoretical physics to crack open a new frontier in ionization science.
The research took place over two years at the Advanced Research Complex at uOttawa, a world-class facility where scientists probe the tiniest structures of matter using cutting-edge lasers and high-powered beams.
The Light Bulb Moment: Vortex Beams and Orbital Angular Momentum
What makes their discovery so exciting? It all comes down to a special type of laser beam called an optical vortex beam.
Imagine a flashlight. Normally, its beam sends light in a straight line. But an optical vortex beam works differently. It twists as it travels, like a spiraling tornado of light. This twist gives the beam a property known as orbital angular momentum (OAM). You can think of it as light carrying a “spin,” or a kind of rotational energy, in addition to moving forward.
By using these spiraling beams, the Ottawa researchers found they could do something nobody thought was possible: control the exact moment and direction an electron escapes an atom during ionization.
“We’ve demonstrated that by using optical vortex beams—light beams that carry angular momentum—we can precisely control how an electron is ejected from an atom,” explains Professor Bhardwaj. “This discovery opens up new possibilities for enhancing technology in areas such as imaging and particle acceleration.”
The Handedness of Light: Left or Right Makes All the Difference
The team discovered that the “handedness” of the light beam, meaning whether it twists to the left or to the right, has a huge impact on ionization. It’s like turning a screw—twist it one way, and it tightens; twist it the other, and it loosens. Similarly, the researchers found that by adjusting the twist of the vortex beam, they could enhance or suppress ionization.
They also played with the “null intensity region” in the center of the beam—essentially a dark spot where there’s little or no light energy. By moving this dark core to different positions, they achieved something remarkable: selective ionization. That’s a fancy way of saying they could choose which atoms or molecules ionize and which ones don’t. This ability introduces a novel concept called optical dichroism, where the behavior of matter changes depending on the direction of the light’s twist.
Why This Matters: From Better Imaging to Quantum Tech
This isn’t just an academic exercise. The ability to control ionization has real-world applications across multiple industries.
In medical imaging, for example, better control of ionization could lead to clearer X-rays and more precise imaging techniques that require less radiation. For semiconductor manufacturing, it could make lithography—the process of carving out circuits on microchips—faster and more efficient. And in quantum computing, where manipulating individual particles is essential, this technology could offer a new level of precision.
“This isn’t just about physics textbooks,” Bhardwaj says. “It could lead to better medical imaging, faster computers, and more efficient ways to study materials. It’s especially promising for quantum computing, where controlling individual particles is crucial.”
And then there’s the potential for attosecond science, which deals with time frames so short they make a blink of an eye seem eternal. Attosecond lasers can capture the movement of electrons in real time, and this new ability to control ionization will give scientists sharper tools for observing and manipulating the subatomic world.
Rewriting the Rulebook on Ionization
For decades, the prevailing wisdom was that strong-field ionization—where intense lasers strip electrons away from atoms—was more or less a brute-force process. Shine enough light on something, and the electrons will fly free. How or when they did that wasn’t something researchers thought they could easily control.
But now, this study suggests otherwise.
By tweaking the angular momentum of light, the Ottawa team demonstrated that ionization isn’t just a matter of intensity, but also of structure and control. It’s like going from a sledgehammer approach to one more like a surgeon’s scalpel.
“Changing the way we think about how electrons are ejected has been challenging,” says Bhardwaj. “But our research proves that using advanced laser technologies can lead to new discoveries that impact both science and technology.”
What’s Next? Exploring New Frontiers
This is just the beginning. The team’s findings open the door to a host of new research questions. Can vortex beams be tailored to control ionization in complex molecules or biological systems? Could this technology one day allow us to manipulate chemical reactions with light beams, or create new states of matter?
At the Advanced Research Complex in Ottawa, those questions are already being explored. The team plans to refine their techniques and investigate how different types of vortex beams interact with various atoms and molecules.
They’re also working on practical applications. “We are interested in transferring this knowledge to industry,” Bhardwaj says. That could mean collaborating with companies that build lasers, imaging systems, or even components for quantum computers.
The Bigger Picture: Light’s Endless Potential
The discovery made by Professor Bhardwaj and his team is a reminder of how light continues to surprise us. What seems like an everyday phenomenon—light—turns out to have layers of complexity and power that we’re only beginning to understand.
Optical vortex beams are one example of how modern physics is reshaping our relationship with light. From fiber-optic communications to high-speed data transmission and laser surgery, light technologies are already central to our lives. This new research promises to take that to an entirely different level.
As scientists continue to uncover the secrets of light and matter, we move closer to a future where controlling the smallest particles in the universe could lead to giant leaps in technology.
Final Thought: Twisting Light, Shaping the Future
At the heart of this discovery is a simple but profound idea: by twisting light, we can shape the behavior of matter itself. It’s a testament to human ingenuity and the spirit of exploration.
As we stand on the brink of new technologies powered by light’s angular momentum, it’s worth remembering that every atom, every electron, and every particle holds untapped potential—just waiting for the right kind of light to unlock it.
And thanks to the team at the University of Ottawa, we’re one step closer to turning that potential into reality.
Reference: Jean-Luc Bégin et al, Orbital angular momentum control of strong-field ionization in atoms and molecules, Nature Communications (2025). DOI: 10.1038/s41467-025-57618-8