Phonon Laser (image) American Physical Society Caption These are schemes for phonon amplification and lasing: (Top) Two coupled microcavities are excited by an optical pulse traveling through an optical fiber (blue). (Center) Pump photons entering through the fiber are converted to lower energy photons and coherent phonons. At a threshold pump power, phonon gain exceeds phonon loss resulting in phonon lasing. (Bottom) Phonon amplification in a superlattice. Tunneling of electrons from one quantum well to the next is accompanied by phonon emission. When a strong phonon wave is applied, it leads to phonon amplification. Credit Alan Stonebraker Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.