Lund University2024-12-162024-12-16https://dspace.academy.edu.ly/handle/123456789/897This thesis describes experiments aimed at developing a key component in applications such as quantum networks and long- distance quantum communication systems: quantum memories. Quantum memories for light using photon-echo and coherent rephasing techniques have been developedt is demonstrated the preparation of optical inhomogeneous absorption profiles such that the light only interacts with a specific transition at a selected frequency. Narrow absorbing structures with widths of <100 kHz have been prepared with no absorption in the surrounding spectral intervalDoped Solids