Amplifying optical spring effect in an optical cavity with an optical parametric amplifier

We demonstrate the ability to manipulate the optical spring (OS) effect by integrating an optical parametric amplifier (OPA) into an optical cavity. The resonance profiles of the OPA cavity were measured as the OPA phase was tuned to both amplification and de-amplification modes. Our observation revealed changes in the effective cavity linewidth, a twofold increase in the OS frequency shift, and a fourfold enhancement in the optomechanical damping under OPA amplification. The method can be applied to gravitational wave detectors in a detuned signal recycling configuration to enhance peak sensitivity within a narrow band. The OS frequency can be tuned to align the detector's peak sensitivity frequency with known continuous gravitational wave signals, dynamically adjusted to track the gravitational wave signal from merging compact binaries, or optimized to search for the post-merger signal of known binary coalescence.