Woodruff School of Mechanical Engineering

Seminar

Title:

Nanoscale thermal radiation and its application to energy conversion

Speaker:

Dr. Dakotah Thompson

Affiliation:

University of Michigan, Department of Mechanical Engineering

When:

Wednesday, October 3, 2018 at 11:00:00 AM

Where:

GTMI Building, Room Auditorium

Host:

Dr. Baratunde Cola
baratunde.cola@me.gatech.edu
404-385-8652

Abstract

Understanding radiative thermal transport is central to a host of scientific fields, from climate science to astrophysics, and is critical for enabling technological advances in energy conversion and thermal management. However, the fundamental framework we use today to describe thermal radiation and radiative heat transfer (RHT), developed over a century ago by Max Planck, is not generally correct and may break down completely at the nanoscale. Despite the importance of understanding the limits of Planck’s laws, there has been a dearth of experimental studies exploring radiative thermal transport at sub-micron and nanometer length scales, primarily due to numerous technical challenges. In this talk I will discuss detailed experimental work, enabled by picowatt-resolution, resistance thermometry-based calorimetry, that probes two distinct limits where Planck’s laws dramatically fail. I first explore the RHT between two bodies in the limit where the gap separation is reduced to less than 100 nm, demonstrating that giant enhancements in RHT can be achieved. I then explore a second limit where the bodies themselves have nanometer dimensions and observe that RHT between these small bodies can greatly exceed Planck’s predictions even for macroscopic gaps. The physical insights and experimental techniques from these works are then leveraged to demonstrate several unique applications including thermophotovoltaic energy conversion, thermal rectification, and active thermal switching. In aggregate, the goal of this talk is to address a few key questions in the field of radiative thermal transport: How general are Planck’s laws? How can thermal radiation be experimentally probed at the nanoscale? If Planck’s laws can be broken, what are the technological ramifications?


Biography

Dakotah Thompson received his B.S. in Mechanical Engineering at the Georgia Institute of Technology in 2012, and received two Institute Research Awards for his creative work combining thermal metrology, nanoscale science, and art. He recently received his M.S. and Ph.D. at the University of Michigan in the Mechanical Engineering department, and was a recipient of the prestigious NSF Graduate Research Fellowship. His research focuses on developing sensitive tools/techniques to experimentally probe radiative thermal transport at sub-micron and nanometer length scales