  Performing interferometry in an optical lattice formed by standing waves of
light offers potential advantages over its free-space equivalents since the
atoms can be confined and manipulated by the optical potential. We demonstrate
such an interferometer in a one dimensional lattice and show the ability to
control the atoms by imaging and reconstructing the wavefunction at many stages
during its cycle. An acceleration signal is applied and the resulting
performance is seen to be close to the optimum possible for the time-space area
enclosed according to quantum theory. Our methodology of machine design enables
the sensor to be reconfigurable on the fly, and when scaled up, offers the
potential to make state-of-the art inertial and gravitational sensors that will
have a wide range of potential applications.
