A single-electron transistor embedded in a nanomechanical oscillator realises an extreme limit of electron-phonon coupling. It performs fast and sensitive electromechanical measurements but also introduces backaction forces, due to the tunnelling of individual electrons, which randomly perturb the mechanical state. Despite the stochastic nature of this backaction, under conditions of strong coupling it is predicted to create a self-sustained state of coherent mechanical oscillations. I will show how we verify this prediction using time-resolved measurements of a vibrating carbon nanotube transistor.

This electromechanical oscillator has intriguing similarities with a laser, with the population inversion provided by the electrical bias and the resonator acting as a phonon cavity. I will show that the resulting emission has the same coherence as a laser, and demonstrate other laser behaviour including injection locking and feedback narrowing of the emitted signal.