  In this chapter, we will describe the storage and retrieval of quantum light
(heralded single photons and entangled photons) in atomic ensembles in a solid
state environment. We will consider ensembles of rare-earth ions embedded in
dielectric crystals. We will describe the methods used to create quantum light
spectrally compatible with the narrow atomic transitions, as well as possible
protocols based on dipole rephasing that can be used to reversibly map the
quantum light onto collective atomic excitations. We will review the
experimental state of the art and describe in more detail quantum light storage
experiments in neodymium and praseodymium doped crystals.
