Mohammad publishes in Physical Review Letters

Mohammad has published in Physical Review Letters. The title of his publication is “Precision Measurement of Phonon-Polaritonic Near-Field Energy Transfer between Macroscale Planar Structures Under Large Thermal Gradients”. Abstract: Despite its strong potentials in emerging energy applications, near-field thermal radiation between large planar structures has not been fully explored in experiments. Particularly, it is extremely challenging to control a subwavelength gap distance with good parallelism under large thermal gradients. This article reports the precision measurement of near-field radiative energy transfer between two macroscale single-crystalline quartz plates that support surface phonon polaritons. Our measurement scheme allows the precise control of a gap distance down to 200 nm in a highly reproducible manner for a surface area of 5×5  mm squared. We have measured near-field thermal radiation as a function of the gap distance for a broad range of thermal gradients up to 156K, observing more than 40 times enhancement of thermal radiation compared to the blackbody limit. By comparing with theoretical prediction based on fluctuational electrodynamics, we demonstrate that such remarkable enhancement is owing to phonon-polaritonic energy transfer across a nanoscale vacuum gap. [Synopsis: Thermal Radiation Gets a Boost] [link]

Cedric passes his PhD qualification exams

Cedric has passed his PhD qualification exams. To be officially considered as admitted to candidacy in the Ph.D. program, applicants must pass a qualifying exam. The qualification exams are the first of three major steps in the Mechanical Engineering PhD program at the University of Utah. Students select two subject areas which support their Ph.D. research. The topics cover fundamental material with the expectation of a graduate-level understanding of the subjects. Cedric took his qualification exams in the subject areas of thermodynamics and heat transfer.