Robust force sensing for a free particle in a dissipative optomechanical system with a parametric amplifier

TL;DR

This paper demonstrates that a degenerate parametric amplifier in a dissipative optomechanical system can significantly enhance force detection sensitivity, surpassing the standard quantum limit even with thermal noise and damping.

Contribution

It introduces a theoretical method to improve force sensitivity beyond the SQL using a parametric amplifier in dissipative optomechanics.

Findings

Force sensitivity surpasses SQL over broad frequency range.

High parametric gain enhances robustness against noise.

Sensitivity improvement factor of about 7 at 1 K temperature.

Abstract

We theoretically investigate optical detection of a weak classical force acting on a free particle in a dissipative coupling optomechanical system with a degenerate parametric amplifier (PA). We show that the PA allows one to achieve the force sensitivity far better than the standard quantum limit (SQL) over a broad range of the detection frequencies. The improvement depends on the parametric gain and the driving power. Moreover, we discuss the effects of the mechanical damping and the thermal noise on the force sensitivity. We find that the robustness of the force sensitivity much better than the SQL against the mechanical damping and the thermal noise is achievable in the presence of the PA with a high parametric gain. For the temperature $T = 1$ K, the improvement in sensitivity is better by a factor of about 7 when the driving power is set at a value corresponding to the SQL with no PA.