Controlling Light At The Nanoscale: PhD Student Abdulhafeez Lukmon Builds Photonic Chips In Tulane's Cleanroom

Inside Tulane’s nanofabrication laboratories, Abdulhafeez Lukmon spends hours working on devices so small they cannot be seen with the human eye. The third-year PhD student in Tulane’s Materials Physics and Engineering program is engineering nanostructures from a special material, vanadium dioxide, to build what's called an active metasurface, designed to manipulate light precisely and dynamically, with potential in many real-world light-based technology applications. At this scale, even humidity in the air can influence the outcome of an experiment, which is why environments like Tulane’s cleanroom laboratories are essential to the work researchers like Lukmon do every day.

Lukmon grew up in Lagos, Nigeria, a dense and fast-moving city that serves as the economic center of the country. As a child, he was fascinated by understanding how things worked.

“There has always been a side of me that liked opening things up and trying to understand how they function,” Lukmon said. “I was always interested in engineering.”

That curiosity eventually led him to Metallurgical and Materials Engineering, a field that explores how the structure and processing of materials determine their properties and performance.

“It is sort of the field that meshes all areas of engineering together,” Lukmon said. “Every field of engineering depends on materials.”

His interest deepened during an industrial training placement at an integrated steel manufacturing plant, where he saw the science he had studied in the classroom applied in real manufacturing processes.

“They would melt steel scrap into liquid steel and adjust the chemistry like cooking,” he said. “You add certain elements in the right proportions to produce the properties you want. That experience helped me connect the theory to the real world.”

After completing his undergraduate studies at the University of Lagos in Nigeria, Lukmon earned a competitive research and teaching assistantship scholarship to pursue a master's degree in Materials Science and Engineering at Khalifa University of Science and Technology in the United Arab Emirates. It was at Khalifa in Professor Matteo Chiesa's Laboratory for Energy and Nanoscience that he further honed his research interests and competencies. Today at Tulane, he is pursuing his doctoral research in the Photonics and Materials Laboratory led by Professor Matthew Escarra.

His research focuses on metasurfaces and nanophotonics, an area that exploits how materials interact with light at extremely small scales.

Right now, Lukmon is working to build what researchers call a two-dimensional transmissive spatial light modulator. The device is designed to control how light behaves.

“We want to control the amplitude of light, which is the intensity, and also the phase of light, which is the position or timing of the light wave in its cycle,” he explained. “When you can manipulate those properties at dimensions smaller than the wavelength of the light itself, you open the door to many different applications.”

Those applications include sensing technologies, telecommunications, optical communications, augmented reality systems and beam steering devices.

To build these devices, Lukmon fabricates structures that are roughly 1000 times smaller than the width of a human hair. The process requires multiple steps that combine material deposition, patterning, and etching using specialized nanofabrication tools.

“We start with a thin film of material,” he said. “Then we use different equipment in the cleanroom to add or remove material so that we can build the structure we need.”

One of the materials Lukmon works with is vanadium dioxide, a compound that has a unique property. Depending on temperature, it can behave either as an electrical insulator or as a metal. “That transition allows us to dynamically change how the material interacts with light,” he said.

In its insulating state, VO₂ is largely transparent to light at the target wavelength. In its metallic state, it primarily absorbs light, with some reflection — effectively switching from transparent to opaque. That contrast enables the device to control light signals dynamically. That ability makes it a promising material for devices that need to dynamically control light signals.

Much of Lukmon’s work involves fabricating nanoscale structures from this material and comparing experimental results with computer simulations. Researchers build models predicting how the structures should behave, then fabricate them and measure how they actually perform.

“Often the result is not exactly what the model predicts,” Lukmon said. “So, we take what we learned and feed it back into the model. Then we adjust the design and try again.” That iterative process is at the heart of experimental materials science. “Most times it does not work,” he said with a smile. “But when it works, we take the little wins.”

Even when experiments fail, Lukmon says the most rewarding moments come from understanding why. “I get more satisfaction from understanding why something worked or why it did not work,” he said. “The more you understand what makes something wrong, the easier it is to move closer to what is right.”

Working at the nanoscale also means researchers must pay close attention to environmental conditions. Humidity, for example, can introduce microscopic moisture onto samples, which can affect how thin films adhere to surfaces or alter chemical processes used during fabrication.

“When we are working at the nanoscale, humidity can affect the adhesion of the film we are depositing,” Lukmon explained. “It can also affect the chemistry of the materials we use during fabrication.”

Even small changes in environmental conditions can make experiments harder to reproduce.

“When you are troubleshooting a result, you want to keep everything constant and only change one parameter at a time,” he said. “If humidity changes, it becomes another variable.”

These are exactly the types of challenges that Tulane’s new Micro/Nanofabrication Facility, opening in Paul Hall later this year, is designed to address. The new cleanroom space will provide tighter control over environmental conditions such as temperature, humidity and contamination levels, helping researchers conduct experiments with greater reliability, repeatability, and performance.

For Lukmon, who still has several years remaining in his PhD program, the new facility represents an opportunity to improve the consistency of his research process. “I am looking forward to being able to move from step to step within the same space,” he said. “That helps eliminate uncertainties in environmental conditions.”

He is also eager to work with the new equipment that will be installed in the facility. “Some of the new tools will allow us to probe our materials in ways we could not before,” he said. “It is not just about doing the experiment. It is about being able to explain why we observe a certain behavior.”

As Tulane’s new cleanroom comes online, Lukmon and other researchers in the Photonic Materials and Devices Lab will be among the first to use the facility. Their work reflects a much larger story about the role materials science plays in shaping modern technology.

“If you look at the history of civilization, it is tied to the materials we learn to control,” Lukmon said. “From the Stone Age to the Bronze Age to the age of semiconductors, each step is driven by advances in materials.”

Today, inside Tulane’s cleanroom laboratories, Lukmon is working at the nanoscale to help write the next chapter.