Of bubbles, sound and metamaterials
acoustic metamaterial
Bubbles are ubiquitous in science and technology: they are key to the working of volcanoes, crucial for dolphins who use them to hunt, determinant in the taste of food. Just like atoms during spontaneous emission, however, bubbles may irradiate sound when probed by a pressure wave: a key phenomenon behind the sound of waves, which is already used in cancer and crack detection. Under stimulated emission conditions, bubbles may even be created by the right sound field: under the general term cavitation, this aspect of bubble dynamics is used to control cleaning, nano-material dispersion and drug delivery.
Starting from bubble-driven technologies, in this talk I will describe something of what I have learned on the interaction between bubbles and sound and how this has brought me to design, here in Sussex, metamaterial-based technologies to precisely shape sound and manipulate objects.
http://www.sussex.ac.uk/materials-physics/site/newsandevents/?id=39354