The new part here is creating two entangled light beams at wavelengths suitable for interacting with trapped atoms.

The general technique of creating entangled beams via OPO has been used for years at other wavelengths, and the resulting beams have been used for quantum optics experiments (including some rather spectacular ones).

What is new here is that by using light at wavelengths that can interact with trapped atoms, there is a possibility to use such atoms as quantum memory.