New JQI Fellow Harnesses Light For Emerging Quantum Tech

Avik Dutt, JQI’s newest Fellow, has his feet planted in two neighboring academic fields: physics and engineering. By bridging the two complementary fields, he pursues projects that both explore new fundamental science and develop devices for practical applications.

Dutt is an Assistant Professor in the Department of Mechanical Engineering and the Institute for Physical Science and Technology at UMD, and he leads a lab focused on both studying the quantum physics of light and developing devices, like quantum sensors, that use the quantum properties of light to exceed the capabilities of existing technologies.

Dutt has been straddling physics and engineering since he was an undergraduate student at the Indian Institute of Technology in Kharagpur, near his hometown. There, he majored in electronics and electrical communication engineering with a minor in physics. In addition to his classes, he worked with a couple of his professors on theory and simulations for research projects in photonics—the field of producing, manipulating and studying individual particles of light called photons.

The topic caught his attention so much that he pursued it as a graduate student. For his doctoral work, he worked under Michal Lipson, first at Cornell University and later at Columbia University when she moved her lab. Working with Lipson and Paulo Nussenzveig from the University of Sao Paulo in Brazil, he moved beyond theory and simulations and gained hands-on experience with experiments and making novel devices. In her lab, he began researching devices that utilize nonlinear optics—phenomena where the intensity of the light in a material alters the material’s interactions with the light, letting the light indirectly influence itself.

After Dutt earned his doctorate in 2017, he wanted to continue with photonics but was interested in broadening his scope and tackling new challenges. Dutt joined the group of Shanhui Fan at Stanford University as a postdoctoral researcher, where he dove into the topic of topological photonics. Like nonlinear optics, topological photonics deals with how light behaves inside matter, but it doesn’t involve light influencing itself. Instead, it deals with material interactions that create special states of light that persist in the face of material imperfections that would disrupt most other states.

As a member of Fan’s lab, Dutt used his practical Ph.D. training to perform experiments that made the group’s theoretical proposals a reality. He worked on a variety of research, including making photons behave as if they were electrons in a magnetic field and using light trapped in a single small device to create two synthetic dimensions.

After his postdoctoral work, Dutt was ready to establish his own lab to build on his past projects and push the boundaries of the photonics devices he worked with. He began applying for faculty positions, and when he received an offer to join UMD as an assistant professor in 2022, it seemed like the perfect opportunity.

“When I got the opportunity to work at UMD, I was like, this is a great choice,” Dutt says. “It has a lot of work in quantum, and it has a lot of work in photonics, and since the main focus of our lab is at the intersection of the two, it made a lot of sense to come here.”

As Dutt built his research group, he recruited members who brought a broad range of perspectives from various disciplines to collaborate on projects that push the boundaries of both science and technology.

“We get fresh ideas from angles we would have never thought of, through interactions with my colleagues in the department, by having students from physics, electrical engineering, mechanical engineering, materials science, sometimes computer science,” Dutt says. “These perspectives that we get—and the things that I get to learn at a faster rate than being in one area—have been very rewarding.”

Synthetic Dimensions, Real Physics
One of Dutt’s projects at UMD is creating artificial spaces with more than two synthetic dimensions, which are simulated dimensions scientists create in experiments by repurposing properties of light, like its color, to represent positions. Synthetic dimensions free scientists from many of the constraints of our familiar three spatial dimensions and are the foundation of experiments where quantum particles can effectively move around and interact in spaces where the scientists have customized the rules and the number of dimensions. By using synthetic spaces, Dutt and his colleagues gain front row seats to physics phenomena, including topological physics, that are often difficult to study even when they arise in lab samples. Adding more dimensions will unlock the chance to observe a host of additional phenomena that don’t exist in fewer dimensions.

In Dutt’s postdoctoral work, he and his colleagues created two independent synthetic dimensions in a single optical resonator—a tiny track where light can race in a tight circle for hundreds of laps, encouraging interactions between the light and the resonator material. The light propagating around the resonator in opposite directions created quantum states with features that the group used to represent synthetic dimensions. In their simulations, the group mapped positions in each synthetic dimension onto distinct ways the light could behave and engineered interactions in the resonator to reflect the physics playing out in the artificial space. However, Dutt needed to expand his toolkit to encode additional synthetic dimensions into resonator-bound light, extending the scope of possible experiments.

Inspired by ideas from his colleagues at UMD and visiting researchers, Dutt realized that he could encode as many synthetic dimensions as he wanted into the states of light if he added a second resonator. His inspiration relied on creating “photonic molecules” using two interacting resonators, which behave much like two hydrogen atoms interacting to form a hydrogen molecule. He saw that unlike an individual resonator, a pair could easily produce additional states capable of forming synthetic dimensions if they were fed multiple frequencies, or colors, of light. With the correct setup, each frequency could race around in a resonator-pair in distinct ways that each represented a position in a synthetic dimension.

In an article published in the journal Nature Physics in June 2023, Dutt and his colleagues described how to encode synthetic dimensions into a photonic molecule created by two interacting resonators, and they proposed new experiments for studying topological physics using those synthetic dimensions. Their proposal explains how to generate any number of dimensions, but as an initial demonstration of the concept, they created just two synthetic dimensions using the technique.

To demonstrate the capabilities of photonic molecules, they used a pair of resonators made of optical fibers—identical to the fibers that use light to carry data across the internet. The optical fibers don’t make ideal resonators for the experiment, but they provided a convenient way to test the idea quickly. The researchers then used the photonic molecule to simulate the two-dimensional physics of a Chern insulator—a material that allows a current of electrons to flow around its edge with no resistance but prevents them from passing through its bulk. Even with the imperfect resonators that they used, the group observed telltale signs of a current forming in their simulated material with associated topological effects.

The researchers also proposed future experiments that Dutt plans to eventually perform using more refined devices. In the article, they presented classical simulations showing how those future experiments could use synthetic dimensions to generate additional topological behaviors for researchers to study.

Dutt says that the single pair of resonators will still be enough to explore higher numbers of synthetic dimensions. Adding additional frequencies of light into the resonators lets researchers extend the artificial space into three dimensions and beyond­—all without making the device any more complicated.

“This was quite interesting, because other real or synthetic dimension platforms could not do this to build higher dimensions,” Dutt says. “We would need to increase the complexity of the physical system, or we could get some weird effects that we do not want.”

Squeezing Out New Advantages
At UMD, Dutt has also used resonators to build on his graduate research into nonlinear optics. A major effort in his lab is to use nonlinear optics to create special “squeezed” states of light in tiny, compact chips, by harnessing advanced manufacturing processes similar to the ones used for making silicon computer chips. Dutt and his colleagues are working to squeeze light while also miniaturizing the size of the light sources by a thousand times or more.

Squeezed light doesn’t mean squeezing an intense amount of light into a small pulse like a laser weapon in a sci-fi movie. Instead of squeezing light’s energy into a small space, it’s about pushing around the quantum uncertainty present in the light. The process of squeezing light essentially uses the quantum uncertainty principle to trade more uncertainty in one of the properties of the light for less uncertainty in another property. The best-known quantum uncertainty principle is Heisenberg’s original uncertainty principle, which dictates a limit on how precisely an object’s position and velocity can be specified simultaneously. However, there are countless quantum properties besides position and momentum with tradeoffs governed by similar uncertainty principles.

For light, accurately measuring the electric field strength comes with tradeoffs to measuring the light’s phase, which indicates the position along the troughs and peaks of a light wave. Squeezed light has had the quantum mechanical uncertainty squeezed out of its electric field strength at specific phases—or conversely has more certainty in measurements of the phase at the expense of how well scientists can measure the electric field strength.

Uncertainty principles come with a striking consequence: Perfect vacuum and complete darkness can’t exist. The principles dictate that we can’t observe the energy of any quantum system—even nothingness—to be zero with no uncertainty. Particles always jiggle slightly and space is never completely empty if you look carefully enough. In real-world experiments, physicists have confirmed that a variety of measurements, even of the darkest vacuum, show fluctuations matching the idea of very short-lived particles—dubbed virtual particles—constantly popping into and out of existence. But the uncertainty principle that relates energy and time also dictates that each virtual particle’s existence is fleeting.

Virtual particles provide a background fizz that exists alongside the more persistent particles that physicists deal with. Even in a totally dark vacuum, researchers always find random fluctuations in their measurements—also known as noise—related to the virtual particles.

Squeezing light can decrease the background noise of its phase or field strength by forcing its uncertainty to the other. Decreasing noise is critical for high-precision measurements, and light is a versatile tool for performing measurements. For instance, in atomic clocks, light enables the most precise timekeeping ever achieved, and the sensors of gravitational wave detection experiments, such as LIGO, currently use squeezed light, produced with large setups, to measure the positions of massive mirrors with unprecedented accuracy.

By squeezing light, Dutt and other researchers force its noise to unnaturally low levels.

“I find it quite remarkable that you can have a bright laser beam of light which has lower noise than complete darkness,” Dutt says. “And because it's lower noise, this enables a lot of applications.”

In an article published in the journal Optica in Feb. 2025, Dutt and his colleagues described devices they developed that provided an unprecedented ability to squeeze light. Previous work had already produced light with noise below the threshold seen for darkness—some squeezing light so that its noise was down to around 60% of the noise of a dark vacuum, but there was room for improvement in the amount of squeezing, the stability of the produced light and the repeatability of the results. With their new experiment, Dutt and his colleagues pushed the noise in their measurements down considerably further and produced light with a noise level equivalent to approximately 40% of the noise of darkness. The team also laid out how their devices produce these squeezed quantum states with long-term stability, circumventing the usually fragile nature of quantum states.

For the experiment, the team made resonators that were each around 100 micrometers across—similar to the width of a human hair or a grain of table salt. The researchers sent light into resonators and got out new photons at a different frequency. The resonator interacts with the input light and ensures that the new photons always come in pairs and form a beam of squeezed light.

In the experiment, the resonators squeezed light more than previous devices while also being smaller and compatible with processes used for mass production. The devices also have the advantage of being capable of simultaneously working with a broad range of frequencies, which could help move information around quickly if used for quantum computing and communication.

Moving forward, Dutt plans to refine the devices to increase how strongly light interacts inside them, and to look at using the resonators as not just a source of squeezed light but also as a means of encoding information and generating additional useful quantum states—such as entangled photons that share a quantum link.

“The most significant achievement of my lab right now is to have world record numbers of squeezing across a large number of modes and spanning a bandwidth of more than 10 terahertz,” Dutt says. “It is an enabling quantum resource for many quantum technological applications.”

Building Communities
Dutt is pursuing a variety of other projects. For instance, as a fellow of the National Quantum Laboratory (QLab) at UMD, he has access to a quantum computer, available through a collaboration with the quantum computing company IonQ, to develop quantum simulations of the interactions that give materials their properties.

He says that at UMD, he has benefited from collaborations with other members of JQI. For instance, JQI Fellow and Co-Director Kartik Srinivasan, who has experience working on the material silicon nitride, has assisted Dutt, who uses the material as the foundation of his devices that squeeze light. Additionally, JQI Fellow Mohammad Hafezi, who also investigates nonlinear optics, has been a valuable collaborator on his projects. JQI research scientist Alessandro Restelli has also helped Dutt and members of his lab develop new techniques and equipment for measuring squeezed light that minimizes the amount of electronic noise added and keeps the light as squeezed as possible.

Dutt is also giving back to the UMD community by sharing his expertise with students. The experiments in his lab not only give students the chance to explore both engineering and physics, but also to learn a variety of skills, like programming classical and quantum computers or fabricating materials in clean room facilities. Dutt is eager to pass on the early mentorship he benefited from, and he has had more than 15 undergraduate students work in his lab since 2022 along with the seven graduate students working toward a Ph.D. Dutt says the students have been beneficial to his work and his investigation of a broad range of technologies.

“Name almost any technology that is common to our surroundings, be it sensing, communications or computing, and photonics seems very well poised to play a role in them,” Dutt says. “So, I definitely feel very excited about having the opportunity to work with extremely talented students in this field.”