Spinning giant optomechanical cavity with nonreciprocal self-interference

Abstract

We study a spinning optomechanical cavity that is coupled to a meandering waveguide at multiple spatially separated points, forming a giant-cavity configuration. The resulting self-interference makes the effective optical driving, linewidth, and frequency shift strongly dependent on the propagation phase in the waveguide, while the rotation-induced Sagnac-Fizeau shift causes the clockwise (CW) and counterclockwise (CCW) cavity modes to experience distinct interference phases. Under single-tone driving, this mechanism enables phase-controlled phonon cooling and, in the presence of cavity rotation, nonreciprocal cooling, with one propagation direction approaching the mechanical ground-state regime while the opposite direction remains less efficiently cooled. Under two-tone driving, the same interference mechanism engineers a squeezed reservoir for the mechanical mode, producing steady-state squeezing that likewise becomes nonreciprocal under cavity rotation. These results establish multi-point self-interference as a versatile mechanism for phase-controlled optomechanical reservoir engineering and show that, when combined with cavity rotation, it provides a route to nonreciprocal quantum effects.