Laser Focused

When Alan Wang, Ph.D., was a child, electric lighting was still something of a novelty in his part of the world.

Growing up in a small rural town in China, Wang, Baylor University’s School of Engineering and Computer Science (ECS) professor and Mearse Chair in Biological and Biomedical Engineering, was 4 years old when his community and home were first wired for electricity in the early 1980s. A few years later, Wang’s family acquired the first television set in their town, and they were happy to share the wonder of it with the neighbors … and the neighbors’ neighbors.

“We would put the television out in the front yard, and when a popular show would come on, maybe 100 people would gather in front of our house to watch this tiny 12-inch, black and white television with the people in the back of the crowd standing on benches, trying to see the picture.”

Wang smiled when he shared this memory. Those simple, early childhood years, in a village with no kindergarten to attend, gave him the time and space to explore his own imagination as a budding engineer.

“I would collect wood and different things to build myself a kite, a handmade fishing pole, a little car or even a homemade rocket by taking the gunpowder from a match and putting it inside a hollow wheat straw — it was all a lot of fun,” Wang recalled. “I’m just a curious person. I’ve always been interested in something.”

The “something” that caught Wang’s attention in second grade, though, would become a steady throughline throughout his life: the properties, beauty and uses of light. In class one day, a 7-year-old Wang learned that when white light passes through a glass prism, it separates into the colors of a rainbow. This phenomenon struck a fascination in Wang that has followed him throughout his education and halfway around the world, from undergraduate and graduate school in Beijing to completing his doctoral degree in electrical and computer engineering from the University of Texas at Austin, and all the way to the frontlines of the photonics frontier.

Over his career, Wang has produced more than 120 journal articles, 140 conference publications and seven U.S. patents. From his work as chief scientist at a specialized photonics and optical research firm to academic pursuits at Oregon State University followed by his move to Baylor in 2022 — when the National Science Foundation named his work a Top-5 Breakthrough of the Year in any field — Wang’s career has consistently pushed forward the development of next-generation photonic materials, devices and systems in the fields biological and biomedical engineering and in ways that have captured the attention of major research funders and industry partners.

In the last four years alone, Wang’s research projects within ECS have garnered more than $5.25 million in funding. One of the most recent grants, $419K from the National Science Foundation, is allowing Wang to seek an answer to a question that sounds almost like science fiction: Can a laser be grown by a living organism?

It’s an idea that was sparked more than a decade ago, when one of Wang’s graduate students at Oregon State walked into his office carrying a picture of a microscopic organism. The student was studying microalgae called diatoms and noticed that their intricate shells looked remarkably similar to the photonic crystal structures Wang was teaching about in class. Naturally, Wang got curious.

While human-made photonic crystals — used in biomedical and environmental sensing — require expensive, sophisticated fabrication, diatoms grow intricate glass-like shells whose natural structures are already perfect for manipulating light.

The limitation was that diatoms could manipulate light but not produce it. And that’s exactly the puzzle Wang and the Baylor ECS graduate students under his direction are now seeking to solve. Their method? Adding quantum dots — tiny light-emitting semiconductor particles — to the diatom shells, a combination that brings together the precise factors needed for a laser. Early results have been promising, revealing that quantum dots on diatom shells can produce light up to 20 times brighter than on ordinary glass.

Wang’s team is testing two approaches: attaching quantum dots to harvested shells and, more radically, feeding living diatoms specially coated quantum dots so they can incorporate them as they grow. The immediate goal is ambitious but straightforward: demonstrate a working biolaser, then determine whether a laser can actually be grown inside a living diatom.

If successful, these tiny lasers could eventually become powerful tools for biosensing. Unlike conventional lasers, which are physically separate from the sample they measure — not to mention incredibly expensive and complicated to produce — a diatom-based laser could be placed directly into a biological or environmental sample. Molecules could interact with the microscopic laser itself, potentially producing stronger signals and allowing researchers to detect tiny amounts of biomarkers, drug residues or pollutants.

“Being able to mix a tiny biolaser directly with the sample you want to observe — that’s something that has never been done before,” Wang said.

In practical terms, it could mean earlier detection of disease, faster and more sensitive testing of food and water and better ways to identify harmful substances in the environment. Ultimately, a technology that makes these kinds of measurements more accessible could contribute to something much bigger: the health and wellbeing of people and the planet.

While Wang hopes to demonstrate the first biolaser within the first year of the project and explore true biological integration in the following year, he’s also careful not to promise more than the science can yet deliver. The project is still at an early exploratory stage, and there are plenty of unknowns. But uncertainty, he said, is part of what makes this work exciting.

It’s why, almost half a century after first seeing the flick of a switch light up a room and a homemade rocket shoot into the sky, Wang is still exploring what is possible, still asking what might happen if he puts two seemingly unrelated things together in a new way. Now, instead of a hollow wheat straw and a match, he has a diatom and a quantum dot. That driving force of joyful curiosity, though? That hasn’t changed a bit.