Keynote 4 New Acoustics, Based On Metamaterials
Date/Time Friday, 3 May 2013 / 08:30 – 09:10
Venue Riverfront Ballroom

Dr. Woon Siong GAN
Acoustical Technologies Singapore Pte Ltd, Singapore

Woon Siong Gan obtained his BSc in physics in 1965, DIC in acoustics and vibration science in May 1967 and PhD in acoustics in Feb 1969, all from the physics department of Imperial College London. He did his postdoctoral works in Imperial College London, Chelsea College London and the International Centre for Theoretical Physics, Trieste, Italy. He was an associate professor in the physics department of Nanyang Univeristy, Singapore from 1970 to 1979. He practiced as an acoustical consultant from 1979 to 1989 and he founded Acoustical Technologies Singapore Pte Ltd, a research & technologies company in ultrasound technologies, especially in acoustical imaging in 1989. His company has invented and patented the scanning acoustic microscope and surface acoustic wave devices. His research interest are in the application of gauge theory to acoustics especially the metamaterials and the application of statistical mechanics and gauge field theory to turbulence. He is the first to propose turbulence as a second order phase transition in 2009 and has subsequently been confirmed by Prof Nigel Goldenfelds group in University of Illinois and Prof Gregory Falkovitchs group in Weizmann Insitutue of Science. His second hypothesis is turbulence is a form of condensation and there is a unique pairing in turbulence analogous to the Cooper pairing in Bose Einstein condensate. He has published several papers on the application of gauge invariance to acoustic fields and the application of spontaneous broken symmetry to turbulence and the book Acoustical Imaging: Techniques & Applications for Engineers published by John Wiley & Sons in 2012. He is lised in Whos Who in the World, Marquis Whos Who several times since 1985.

The author proposed in 2007 the application of gauge invariance approach to acoustic fields, revolutioning and rewriting the whole field of acoustics has come true eventually to the various groups in the world working on various aspects of the theories and novel applications of acoustical metamaterials. Metamateial can control and manipulate the direction of sound propagation in solids and in fluids. This affects the refraction, scattering, and diffraction, the three basic mechanisms of sound propagation in solids. Hence the author coined the term new acoustics for this. In this lecture various applications of metamaterial, both double negative and bandgap types will be described. This will include several other areas besides just negative refraction and acoustical cloaking. Application to be mentioned are acoustical waveguides, resonators, filters in communications, diffraction tomography for negative inclusion, vibration propagation in negative material, the layered model for layers of positive material and negative material and last but not least the application of metamaterial to nonlinear acoustics manifested in acoustic diode which shows broken symmetry in reciprocity theorem in nonlinear phononic crystal such as superlattice. Due to nonlinearity and the bandgap properties of superlattice, sound only propagates only in one direction instead of the symmetrical two ways traffic in a linear acoustic system.