Quantum Optics with Rare-Earth Doped Crystals

Rare-earth atoms in solids have many different qualities that make them good candidates for quantum memory including excellent coherence properties, large optical depth, and compatibility with integrated photonics. We use the large optical depth, long spin-state lifetime, and large ratio of inhomogeneous to homogeneous optical lifetime in Pr:YSO to spatially and spectrally tailor the Pr ensemble to implement dynamically reconfigurable, cavity-enhanced quantum memory. This is enabled via spectral hole burning to create Bragg gratings of spectral sub-populations of Pr atoms inside the crystal. We expect to be able to achieve high reflectivity in this regime, and also to implement active switching of the reflectors with an additional control field, by taking advantage of the level structure and other properties of Pr:YSO. This will enable the creation of dynamically tunable optical cavities, which can be coupled to additional Pr ensembles via additional spectral hole-burning processes enabling cavity enhanced quantum memory. We will present initial experimental progress investigating spectral hole-burning and theoretical calculations of expected reflectivity and switching properties with realistic parameters.