1 research outputs found
Multiple Reflections and Diffuse Scattering in Bragg Scattering at Optical Lattices
We study Bragg scattering at 1D atomic lattices. Cold atoms are confined by
optical dipole forces at the antinodes of a standing wave generated inside a
laser-driven cavity. The atoms arrange themselves into an array of lens-shaped
layers located at the antinodes of the standing wave. Light incident on this
array at a well-defined angle is partially Bragg-reflected. We measure
reflectivities as high as 30%. In contrast to a previous experiment devoted to
the thin grating limit [S. Slama, et al., Phys. Rev. Lett. 94, 193901 (2005)]
we now investigate the thick grating limit characterized by multiple
reflections of the light beam between the atomic layers. In principle multiple
reflections give rise to a photonic stop band, which manifests itself in the
Bragg diffraction spectra as asymmetries and minima due to destructive
interference between different reflection paths. We show that close to
resonance however disorder favors diffuse scattering, hinders coherent multiple
scattering and impedes the characteristic suppression of spontaneous emission
inside a photonic band gap