Performance of a cold-atom gravimeter with an active vibration isolator

Abstract

A cold rubidium atom fountain interferometry gravimeter with an active vibration isolator is demonstrated. The natural resonance frequency of the active vibration isolator is 0.016 Hz, and the vertical vibration noise is greatly reduced by a factor of 100 from 0.1 to 1 Hz. After substantial suppression of the vibration noise, the gravimeter reaches a sensitivity of ${5.5\ifmmode\times\else\texttimes\fi{}10}^{\ensuremath{-}8}$ g/Hz${}^{1/2}$. We measured the local gravitational acceleration $g$ by this sensitive gravimeter with a resolution of ${6.5\ifmmode\times\else\texttimes\fi{}10}^{\ensuremath{-}9}$ g after 60 s and ${1.5\ifmmode\times\else\texttimes\fi{}10}^{\ensuremath{-}9}$ g after 2000 s integration time, which is comparable to the resolution of state-of-the-art atom gravimeters.