Exceptional Points in Random-Defect Phonon Lasers

Intrinsic defects in solid-state devices are generally seen as detrimental to coherent amplification of phonons (phonon lasing), and thus fabricating devices with as few defects as possible has been key in optomechanics and nanoelectromechanical systems. However, the authors show that by surpassing an exceptional point in the parameter space of the non-Hermitian system, mechanical gain can be enhanced d00exe00exs00exp00exi00ext00exe increasing defect-related losses. This counterintuitive effect is analogous to loss-induced optical lasing, and offers a remarkable way to operate and utilize quantum acoustic devices.