2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/170410The future of long-distance quantum communication relies on the availability of quantum memory, i.e. devices that allow temporal storage of quantum information. We review research related to quantum state storage based on a photon-echo approach in rare earth ion doped crystals and glasses.20 pages including 13 figures and 182 references, review articleQuantum Physicstext