The Coke can acoustic lens, surrounded by speakers, can focus sound waves to a space 1/25th the size of a wavelength. Image credit: Fabrice Lemoult (PhysOrg.com) -- When trying to focus sound waves ...
IT has been well established 1,2 that, in the case of diffraction of light by very-high-frequency sound waves only the first order of diffraction appears in the field of view and it attains the ...