An emerging technology that uses lasers to measure temperature at microscopic scales could pave the way for faster, more powerful computing devices, longer-lasting batteries and more, according to a University of Virginia professor and his colleagues. “The limiting factor in all device designs right now is the heat,” said Patrick Hopkins, Whitney Stone Professor of Engineering and co-author of an article in Nature Reviews Methods Primers, a publication of the journal Nature. “That’s why iPhones can’t be faster, computers can’t be faster, servers can’t be faster.” Hopkins, who earned his undergraduate and graduate degrees at UVA, teaches in the School of Engineering and Applied Science’s Department of Mechanical and Aerospace Engineering. The journal approached him and his co-authors to create a guide to build and use a method called time-domain thermoreflectance, or TDTR, a technique for measuring temperature change at very small scales. Hopkins’ Experiments and Simulations in Thermal Engineering (ExSiTE) lab at UVA specializes in laser-based techniques that are uniquely capable of characterizing thermal properties at the smallest time and space scales. The Way to Smaller, Faster Devices Understanding these properties is fundamental to developing new materials for ever-shrinking devices that can stay cool while delivering the computing power that today’s technologies — such as generative AI or high-density energy storage — demand. TDTR helps provide that fundamental knowledge, and it’s becoming more important as researchers work with smaller and smaller materials, Hopkins said. The technique is showing up in research across fields like quantum computing, semiconductor materials and battery technology. The Nature Reviews Methods Primer article gives future researchers a primer on the technique, so it could be more widely used in other areas of research. Hopkins, who also holds courtesy appointments in the materials science and engineering and physics departments, co-authored the paper with Ramya Mohan, a