Microscopic LEDs no wider than a human hair could soon replace lasers in key applications like data transmission within server racks and next-generation displays, according to new research from UC Santa Barbara. Doctoral student Roark Chao, who is studying electrical engineering, is at the forefront of this advancement, co-authoring a study published in Optics Express that outlines a breakthrough design for microLEDs. "These devices are literally the size of a hair follicle," Chao said. "With the right engineering, we can control how the light emerges, making these microLEDs viable alternatives to lasers in short-distance data communication." The research builds on UC Santa Barbara’s long-standing expertise in gallium nitride materials and optoelectronics. Chao is co-advised by Steven P. DenBaars and Jon A. Schuller, both co-authors of the study, which also includes Nobel laureate Shuji Nakamura, whose groundbreaking work on blue LEDs revolutionized lighting and display technologies. The experiments were conducted in the DenBaars/Nakamura and Schuller laboratories, where teams specialize in growing high-quality gallium nitride materials and developing nanoscale photonic devices. The team introduced a novel microLED design that significantly enhances both light efficiency and beam directionality. By surrounding the light-emitting region with lateral distributed Bragg reflectors, the researchers achieved about 20% higher optical output through air-side emission, over 130% higher output through the substrate side, and roughly 30% less beam divergence compared to standard microLEDs. In addition to better beam control, the new design delivers superior electrical performance. The microLEDs showed approximately 35% higher electrical efficiency and nearly 46% higher wall-plug efficiency—meaning they convert a much greater share of input power into usable light than conventional microLEDs. One of the biggest advantages over lasers is thermal resilience. "Lasers start running into thermal issues at relatively low temperatures," Chao explained. "MicroLEDs can operate at much higher temperatures without complex cooling systems, reducing maintenance, replacement costs, and increasing flexibility in data center environments." As cloud computing and artificial intelligence drive demand for faster, more efficient data transfer, even small improvements in light sources can yield major economic and operational benefits. "What's exciting about microLEDs is that they offer multiple solutions in one technology," Chao said. "They can boost data communication, enable brighter and thinner displays, and support emerging applications like augmented and virtual reality—all using the same core platform." Chao joined UC Santa Barbara as an undergraduate electrical engineering student in 2020 and transitioned into doctoral research shortly after. He credits the university’s integrated research ecosystem—spanning materials growth, nanofabrication, and device testing—as critical to the rapid progress of his work. "You can simulate a design, grow the crystal, fabricate the device, and test it—all on campus," he said. "That seamless flow from idea to experiment is what makes this place so powerful."