We demonstrate a design of a simple scheme for Raman-transition-based large momentum transfer, under which the propagation directions of the Raman beams are effectively swapped by tuning their relative frequency instead of swapping their polarizations.
We present a Raman atom interferometer using large momentum transfer without reversing the direction of the effective wave vector ( k -reversal). More specifically, we use a microwave π / 2 pulse to manipulate the spin state of Rb 87 atoms before applying a Raman light π pulse to achieve 4 ℏ k momentum transfer per Raman light pulse. A microwave π pulse in the middle of the interferometer sequence reverses the spin states, which allows closing of the interferometer arms by the same Raman light π pulses without propagation reversal. We present a proof-of-principle demonstration of a 4 ℏ k large-momentum-transfer (LMT) atom interferometer and discuss its scalability. Our results extend the scope of using LMT atom optics.
An atom interferometer based on Doppler-insensitive Raman transition is proposed, which has sharply peaked interference fringes for multi-wave interference. We show that two sets of counter-propagating Doppler-insensitive Raman beam pairs can be used to construct a new type of multi-wave beam splitter, which can be used to construct an atom interferometer. Although the spacing between adjacent diffraction orders of the interferometer is small, they can be distinguished by the internal state of the atom. Our analysis shows that the width of the fringes of this atom interferometer is inversely proportional to the width (duration) of the beam splitter and the Rabi frequency of the Raman beams, that is, the interferometer can achieve high resolution at high light intensity and long pulse width.
We demonstrate light-pulse atom interferometry with large-momentum-transfer atom optics based on stimulated Raman transitions and frequency-swept adiabatic rapid passage. Our atom optics have produced momentum splittings of up to 30 photon recoil momenta in an acceleration-sensitive interferometer for laser cooled atoms. We experimentally verify the enhancement of phase shift per unit acceleration and characterize interferometer contrast loss. By forgoing evaporative cooling and velocity selection, this method lowers the atom shot-noise-limited measurement uncertainty and enables large-area atom interferometry at higher data rates.
It is proposed to use rectangular Raman pulses for the technique of sequential large momentum transfer. It is shown that the small parameters that make it possible to use this technology for precision atom interferometry can be 40--200 times smaller than in the case of the Bragg regime. It is predicted that in the case of a nonequidistant timing of auxiliary pulses, one can observe oscillations in time of the interference picture with a period inversely proportional to the recoil frequency. Such an observation would be confirmation that Mach-Zehnder atom interference is a phenomenon caused by the quantization of the atomic center-of-mass motion. This effect is calculated for any shape of pulses. One can observe it in the Bragg regime as well. It is proposed to use noncontinuous composite Raman pulses as auxiliary beam splitters so that the effective Rabi frequency remains unchanged for the entire process. The gravity phase of an atomic interferometer is calculated for any shape, duration, and timing of Raman pulses, including the Bragg regime. The phase corrections caused by the finite pulses' durations are also calculated for the rectangular Raman pulse shape.