Guest Speaker: Prof. Oliver B. Wright
Hokkaido University
Oliver B. Wright has been a Professor at Hokkaido University, Japan since 1996 and an Invited Professor at Osaka University, Japan since 2022. He received his BA in physics at the University of Oxford and his PhD in physics from the University of Cambridge. His current research interests include picosecond laser ultrasonics, acoustic wave imaging, and acoustic metamaterials. He founded Plum Science, Co., Ltd. in 2013, which makes and distributes design lighting systems.
Abstract
Electromagnetic metamaterials, consisting of sub-wavelength oscillators that show effective negative permeability or permittivity have led to many applications over the last 20 years. In parallel, acoustic metamaterials showing effective negative density or modulus were introduced. Here I will present and review the topic of metamaterial-based extraordinary acoustic transmission, i.e., the passage of more acoustic energy than expected through small sub-acoustic-wavelength apertures.
I will first present our experimental work in this field using kHz airborne acoustics, for which giant transmission was demonstrated, and also simulations in solid acoustics of even more enhanced transmission for bulk waves. Finally, I will present very recent kHz experiments on the transmission of airborne sound through bare holes without the occurrence of any resonance. I will hope to make you appreciate how sound-transparent screens with holes at bank service counters work, and how to optimize them.
