Optical Space Singularities: Ultrasonic Induced Artificial Black Holes   in Phononic Crystals
  Ultrasonic standing waves in a cylindrical enclosure can achieve very high local pressures at the acoustic nodes (~1 MPa). When the acoustic wave passes through a phononic crystal comprised of steel and glycerin, there are regions of constructive interference resulting in even higher local pressures (~100 MPa). At these highly localized pressure points inside the crystal, the equations describing the acoustics break down and the mathematics of gravitational fields are more appropriate. These pressures are so high as to create optical space singularities, analogous to cosmological phenomena. We measure a redshift for light passing through this system and describe how the optical space thus created can be described by elementary equations of a non-rotating black hole. 
Edward A. Rietman
cond-mat.mtrl-sci