2 research outputs found
Interlaced spin grating for optical wave filtering
Interlaced Spin Grating is a scheme for the preparation of spectro-spatial
periodic absorption gratings in a inhomogeneously broadened absorption profile.
It relies on the optical pumping of atoms in a nearby long-lived ground state
sublevel. The scheme takes advantage of the sublevel proximity to build large
contrast gratings with unlimited bandwidth and preserved average optical depth.
It is particularly suited to Tm-doped crystals in the context of classical and
quantum signal processing. In this paper, we study the optical pumping dynamics
at play in an Interlaced Spin Grating and describe the corresponding absorption
profile shape in an optically thick atomic ensemble. We show that, in Tm:YAG,
the diffraction efficiency of such a grating can reach 18.3% in the small
angle, and 11.6% in the large angle configuration when the excitation is made
of simple pulse pairs, considerably outperforming conventional gratings.Comment: 11 pages, 13 figures in Physical Review A, 201
Time reversal of light by linear dispersive filtering near atomic resonance
Based on the similarity of paraxial diffraction and dispersion mathematical
descriptions, the temporal imaging of optical pulses combines linear dispersive
filters and quadratic phase modulations operating as time lenses. We consider
programming a dispersive filter near atomic resonance in rare earth ion doped
crystals, which leads to unprecedented high values of dispersive power. This
filter is used in an approximate imaging scheme, combining a single time lens
and a single dispersive section and operating as a time reversing device, with
potential applications in radio-frequency signal processing. This scheme is
closely related to three-pulse photon echo with chirped pulses but the
connection with temporal imaging and dispersive filtering emphasizes new
features.Comment: 21 pages, 11 figure