The ProQuest Distinguished Dissertation Awards are given out each year to recognize highly accomplished graduate students who have produced outstanding dissertations of the highest scholarly quality in any field of study. For 2018 there were 10 awards given and one was to ME Post-Doctoral Research Fellow, Dakotah Thompson. For his dissertation, Thompson dug deep into a set of questions at the forefront of a cutting-edge field seeking to understand radiative thermal transport at the nanoscale. His dissertation is titled, "Exploration of Radiative Thermal Transport at the Nanoscale Using High-Resolution Calorimetry."
Thompson worked alongside Professor Meyhofer and Professor Reddy of the U-M ME Department as they have been heading the work investigating thermal transport at the nanoscale since the early 2000s. With so much to be learned about this concept, Thompson looked at two distinct limits of the century-old laws of Max Planck for describing thermal radiation. It is predicted that these laws break down when applied to the nanoscale. Experimentally demonstrating this has been difficult due to many technical challenges including the lack of appropriate tools with adequate sensitivity to measure the minuscule heat flows in nanoscale systems. "To enable these experimental studies, I designed and fabricated very sensitive microdevices in the Lurie Nanofabrication Facility at U-M which can measure radiative heat flow rates with picowatt resolution," said Thompson. These new devices, called "calorimeters," led the way for new discoveries.
First, these calorimeters were used to probe the radiative heat transfer between hot and cold objects separated by a gap of fewer than 100 nanometers. It was demonstrated, for the first time, that the radiative heat transfer rate for that gap size can greatly exceed the predictions of Planck's laws by orders of magnitude. For the second experiment, Thompson developed a platform to probe the radiative heat transfer between a hot and cold object separated by a larger gap, but whose physical dimensions were approximately 100 nanometers. This produced findings showing yet again, that the radiative heat transfer rates can exceed the predictions of Planck's laws by orders of magnitude.
With this new research brings on more questions: How far can we push past Planck's laws using these nanoscale size effects? What is the best way to study thermal transport at sub-micron and nanometer scales? What can these advancements bring to the practical world?
We do know that further investigation of this research is important. As a physical phenomenon that is fundamental to several scientific disciplines, better knowledge of thermal radiation can help better understand climate change, enable technological advances that impact how we heat and cool homes, and more efficiently generate electricity.
Congratulations to Dakotah Thompson and we wish him all the best on his continued work.