# Spectrometric detection of weak forces in cavity optomechanics

## TL;DR

This paper introduces a spectrometric technique for detecting weak classical forces in cavity optomechanics by analyzing photon spectra, offering a rapid, noise-resilient measurement method that can also detect oscillating forces.

## Contribution

The paper presents a novel spectrometric approach to measure weak forces in cavity optomechanics, including a method to detect oscillating forces via modulated coupling.

## Key findings

- Force detection via photon spectra is fast and noise-resistant.
- The method can detect both static and oscillating forces.
- Spectrometric analysis provides a new tool for precision measurements in optomechanics.

## Abstract

We propose a spectrometric method to detect a classical weak force acting upon the moving end mirror in a cavity optomechanical system. The force changes the equilibrium position of the end mirror, and thus the resonance frequency of the cavity field depends on the force to be detected. As a result, the magnitude of the force can be inferred by analyzing the single-photon emission and scattering spectra of the optomechanical cavity. Since the emission and scattering processes are much faster than the characteristic mechanical dissipation, the influence of the mechanical thermal noise is negligible in this spectrometric detection scheme. We also extent this spectrometric method to detect a monochromatic oscillating force by utilizing an optomechanical coupling modulated at the same frequency as the force.