Contrast enhancement of echo atom interferometers using optical channeling and optimization of near resonant Bragg scattering

We investigate channeling oscillations in the contrast of a density grating formed by exposing a sample of ultracold atoms to an optical standing-wave pulse. We show that these dynamics can be imprinted on the free-induction decay signal following standing wave excitation as well as on the echo signal associated with a two-pulse atom interferometer (Carlse et al. Phys. Rev. A, 109, 043307 (2024)). Experimental results are supported by a simple model, which describes the grating contrast as the combination of two separate physical effects, namely, matter-wave interference and classical optical channeling resulting in Pendellösung-like oscillations. We also investigate the characteristics of near resonant Bragg scattering (Carlse et al. Phys. Rev. A. 110, 043306 (2024)), the underlying process that produces the echo signal. We explore how the density modulation produced in an atomic sample by momentum state interference and optical channeling can be optimally read out using a coherently Bragg-scattered traveling-wave electric field. When both the channeling and Bragg scattering processes are optimized, we report a 20-fold increase in scattering efficiency.