Phase‐Controlled Quantum Sensing of Weak Forces

ABSTRACT Cavity optomechanical (COM) sensors based on whispering‐gallery‐mode (WGM) resonators have emerged as highly sensitive platforms for probing weak external perturbations, enabling diverse applications from precision metrology to fundamental tests of physics. In this work, a quantum‐enhanced scheme for weak‐force sensing in a WGM resonator is proposed. The system leverages phase control between two coherent driving fields and incorporates realistic imperfections to engineer optical squeezing within the cavity. By finely tuning the relative phase, strong optical squeezing and quantum entanglement between counter‐propagating modes are generated within the cavity, achieving an optimal force sensitivity beyond the standard quantum limit (SQL) and a quantum noise reduction of up to three orders of magnitude. Furthermore, optimal parameter regimes for achieving minimal quantum power spectral density are systematically identified. These findings reveal a new route for phase‐enabled quantum sensing in the high‐quality WGM resonator, with potential implications for high‐precision measurements and quantum information technologies.