Enhancing Optomechanical Entanglement in a Double Laguerre–Gaussian Cavity Optomechanical System via Non-Degenerate Parametric Interactions

Quantum entanglement lies at the heart of numerous quantum technologies, yet macroscopic entanglement remains a long-standing challenge to achieve. Here, we theoretically investigate stationary entanglement between a Laguerre–Gaussian (LG) cavity mode and a macroscopic rotating mirror in a double LG cavity optomechanical system with a non-degenerate optical parametric amplifier (NOPA). The two LG cavity modes interact with each other via a NOPA, and one of them is coupled with a rotating mirror through radiation torque. We employ logarithmic negativity to quantify optomechanical entanglement. We analyze the effects of the gain and phase of the NOPA, the pump powers of the two LG cavity modes, the topological charge and cavity detuning of the LG cavity mode coupled with the rotating mirror, and the environmental temperature affect optomechanical entanglement. We find that the presence of the NOPA can significantly enhance optomechanical entanglement and make it more robust against thermal noise. Our results provide a feasible approach for generating robust macroscopic optomechanical entanglement, which may find applications in quantum sensing and quantum networks.