Atom gratings produced by large-angle atom beam splitters

Abstract

An asymptotic theory of atom scattering by large amplitude periodic potentials is developed in the Raman-Nath approximation. The atom grating profile resulting from the scattering is evaluated in the Fresnel zone for triangular, sinusoidal, magneto-optical, and bichromatic field potentials. Analytic asymptotic expressions are obtained for the Fourier components of the atomic wave function following scattering. It is shown that, owing to the scattering into two groups of momentum states rather than two distinct momentum components, the corresponding spatial density profiles differ significantly from pure sinusoids.having period /2n . The prototype LABS consists of a V potentialoff of which atoms scatter. The function f (t), normalized such that ͐ Ϫ/2 /2 f (t)dtϭ1, describes the potential experienced by an atom in its rest frame ͓tϭx/u, where u is the projection of the atom velocity along the beam propagation direction (x axis͒ and is the pulse duration in the atomic rest frame͔ ͓11͔. It is assumed throughout this paper that the temporal width is sufficiently small to allow the atom-field interaction to be considered in an impulse ͑Raman-Nath͒ approximation. A sufficient condition for the Raman-Nath approximation to hold iswhere m is the atomic mass.In the past several years, a number of methods have been proposed for using counterpropagating optical fields to create PHYSICAL REVIEW A, VOLUME 64, 063612

Atom-wave diffraction between the Raman-Nath and the Bragg regime: Effective Rabi frequency, losses, and phase shifts

“…In certain situations, the neighboring momentum states (considered as "losses" in here) contribute to this, leading to an apparent distortion of the interference fringes. This has been considered for the Raman-Nath regime in [55,56]. An upper limit for this can be given by √ ℓ, by assuming that all the lost population interferes and conspires to produce the maximum effect.…”

Atomic quasi-Bragg-diffraction in a magnetic field

“…This forms a clear distinction with the experiments of Ref. [12], which are performed in the Raman-Nath regime [13].In our configuration the initial transverse momentum of the atoms is zero. Thus, the square of the transverse momentum cannot be conserved in diffraction.…”

“…This forms a clear distinction with the experiments of Ref. [12], which are performed in the Raman-Nath regime [13].…”

Analytic theory for Bragg atom interferometry based on the adiabatic theorem

“…Theoretical models for Bragg diffraction of matter waves from light crystals have first covered the two limiting cases of short and intense or faint and long light pulses referred to as the Raman-Nath [33][34][35] or deep-Bragg regime [16,17] respectively. An introduction to these regimes can be found in the textbook by P. Meystre [36], and an account of individual contributions towards a better understanding of the diffraction from optical lattices was given by Müller et al [37].…”