The atomic recoil from the absorption of up to 60 photons is measured using an atom interferometer. We determine ħ/${\mathit{m}}_{\mathrm{Cs}}$ with a precision of ${10}^{\mathrm{-}7}$ in 2 h of integration time.

• Received 2 February 1993

DOI:https://doi.org/10.1103/PhysRevLett.70.2706