Momentum-resolved detection for high-precision Bragg atom interferometry

We demonstrate a momentum-resolved detection technique in a sensitive Bragg atom interferometer, where the populations of the atomic final states are measured by the Raman spectroscopy method. This method avoids cross-couplings due to the space overlapping of atomic states and significantly increases the fringe visibility without requiring spatial separation. Thanks to this detection method, we are able to achieve the high fringe visibility of greater than 80% at an interrogation time of T = 1 ms. With T = 250 ms and a visibility of 10%, it shows an improved resolution for gravity measurements at the level of 7x 10(-10) g in an integration time of 1000 s. This work can be applied in developing compact portable sensing devices or improving the precision of tests on fundamental physics.