Quantum memories that store and retrieve photonic quantum states are key components for future quantum networks. This thesis investigates efficient optical-to-spin population transfer in Eu³⁺:Y₂SiO₅, a leading platform for atomic frequency comb (AFC) quantum memories due to its long coherence times and excellent spectral properties. Through combined experimental and theoretical work, the optical-to-spin transfer efficiency is increased to 96%, demonstrating near-unity conversion between optical and spin states—an essential requirement for high-performance spin-wave storage.

A validated spin Hamiltonian is established by reconstructing the branching-ratio matrix under a 231 mT magnetic field aligned near the D₂ axis, ensuring isolated transitions and accurate modeling of energy levels and transition strengths. Numerical simulations based on optical Bloch equations reproduce the measured Rabi dynamics and identify optimal control-pulse parameters, while a second model captures optical-pumping dynamics and spectral preparation. Together, these tools provide a quantitative framework for optimizing Eu³⁺:Y₂SiO₅ quantum memories and advancing scalable solid-state quantum storage.