Mechanical & Aerospace Engineering, Rutgers University
Transformation acoustics and cloaking of acoustic and elastic
waves
March 27, 2013
3:00pm PGH 646
Abstract
The concept of transformation optics as applied to cloaking is to map a
region of space into another region with the same outer boundary in such a
way that both regions display the same optical properties as far as the
exterior world is concerned. The talk will discuss how the original ideas
for transformation optics translate to acoustic and elastic waves.
Surprisingly, the acoustic transformation is not unique, unlike the case
for electromagnetic waves. The non-uniqueness means that the same effects
can be achieved using different types of metamaterial in the transformed
domain, ranging from materials with anisotropic density to pentamode
materials. Both of these unusual types of constitutive properties will be
defined and related to the transformation (mapping). Recent work on the
fabrication of pentamode materials (PM) based devices will be described,
and some unexpected properties explained, such as negative index of
refraction. The ideas of transformation optics do not go over completely
for elasticity – the difficulty arises from the presence of two
wave types with distinct speeds. Some recent progress will be discussed.
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Last modified: April 11 2016 - 18:14:43