Spin-selective coherent light scattering from ion crystals

We study collective light scattering from linear crystals with up to twelve ⁴⁰Ca⁺ ions, acting as coherent single photon emitters. Light-scattering is induced by two-photon laser excitation, starting from the S1/2 to D5/2 quadrupole transition at 729~nm in combination with laser excitation of the D5/2 to P3/2 dipole transition at 854~nm, followed by a decay back to S1/2 via a single photon emission near 393~nm. The scattered intensity is recorded in the far field, featuring the interference of emitted light fields of the entire crystal. Furthermore, we demonstrate spin-dependent coherent scattering and unveil the time evolution of a previously encoded spin texture in a crystal employing the recorded dynamics of the spatial frequency components of the fringe pattern.