Laser-like sound amplification: stimulating electrons within a crystal, causing faster than speed of sound phonon burst

https://www.eurekalert.org/news-releases/1125836

"trap electrons in few atoms thick crystal layer restricting movement to 2D making behavior more predictable /wave-like, apply high electric current, electrons energize/ emit sound while surrounding crystal stays near absolute 0... ultrasound imaging through solid metal/ deep biological tissue with much higher resolution, vibrations process data faster/ channel heat away from microchips, medical diagnostics, global communication, sonar... future: graphene crystal for even higher speeds"