phonon laser ?

After decades of lasers, recently people came up with phonon laser setups. The underlying physics is essentially this: phonons, as photons, are bosons. Bosons tend to amplify themselves. In this work [1,2] the authors observed amplification but not lasing so far. So, real phonon laser has to be seen afar.

[1] Phonon Laser Action in a Tunable Two-Level System

Ivan S. Grudinin, Hansuek Lee, O. Painter, and Kerry J. Vahala

Phys. Rev. Lett. 104, 083901 (2010) – Published February 22, 2010

[2] Coherent Terahertz Sound Amplification and Spectral Line Narrowing in a Stark Ladder Superlattice

R. P. Beardsley, A. V. Akimov, M. Henini, and A. J. Kent

Phys. Rev. Lett. 104, 085501 (2010) – Published February 22, 2010