# Ramsey Interferometry based on stimulated Brillouin scattering

## TL;DR

This paper explores two types of Ramsey interference fringes in a whispering-gallery resonator using stimulated Brillouin scattering, revealing quantum properties like squeezing that improve interferometer sensitivity.

## Contribution

It introduces a novel approach to quantum interferometry by utilizing stimulated Brillouin scattering to generate Ramsey fringes in different regimes, including anti-RWA, with enhanced quantum features.

## Key findings

- Anti-RWA Ramsey fringes exhibit quantum squeezing properties.
- The fringes are robust against system decay.
- The method is feasible with current laboratory techniques.

## Abstract

Realizing highly sensitive interferometry is essential to accurate observation of quantum properties. Here we study two kinds of Ramsey interference fringes in a whispering-gallery resonator, where the coherent phonons for free evolution can be achieved by stimulated Brillouin scattering. These two different fringes appear, respectively, in the regimes of rotating wave approximation (RWA) and anti-RWA. Our work shows particularly that the anti-RWA Ramsey interference takes some quantum properties of squeezing, which enhances the strength and visibility of the fringes and shows robustness against the system's decay. In application, our proposal, feasible with current laboratory techniques, provides a practical idea for building better quantum interferometers.