In several labs around the world, sound waves are doing things they've never done before. Teams working in England and the Ukraine have made a sonic laser, or "saser," which operates in the terahertz range, with sound waves oscillating more than a trillion times per second. Meanwhile, in an Israeli lab, researchers say they've created the first ever sonic black hole that traps sound waves and won't let them escape. The saser
uses packets of sonic vibrations called "phonons" much like a regular laser uses photons. Specifically, the acoustic laser device consists of a sonic beam traveling through a "superlattice" constructed of 50 sheets of material each only atoms thick that are alternately made of gallium arsenide and aluminium arsenide, two materials found in semiconductor [CNET].
The phonons bounce back and forth inside the lattice, which causes more phonons to be released and amplifies the overall signal.
The result is ...
