Optomechanical parametric oscillation of a quantum light-fluid lattice

Optical parametric oscillators are one of the building pillars of nonlinear and quantum optics, the basis of minimum-uncertainty quantum states and entangled photon pairs. Transferring similar ideas to mechanical vibrations, the authors demonstrate an optomechanical parametric oscillator based on a lattice of traps that confine and couple fluids of light and sound. Nonresonant continuous laser excitation leads to 20 GHz self-induced oscillations of the phonon field, a coherent process associated with a tailored intertrap coupling that is quadratic in the mechanical displacement.