Optical Memory Optimization Across Rubidium Isotopes and Transitions

We investigate optical memory efficiency and storage time across ⁸⁵Rb and ⁸⁷Rb isotopes on both the D₁ and D₂ transitions. Maximum efficiency of up to 44\% was achieved using the D₁ line in both isotopes, with up to 1.5 ms storage time. %Maximum efficiencies of 44\% were measured for both isotopes on the D₁ line, in agreement within 1σ, while the longest storage time reached is 1.5 ms. These performance levels are enabled by warm vapor rubidium buffer-gas filled cells, large optical depth, and a near-resonant EIT scheme optimized with respect to the one- and two-photon detuning. Our results provide practical guidelines for optimizing the performance of warm rubidium vapor optical memories in simplified experimental configurations. We expect that the optimization approach employed here, specifically operating at elevated temperatures while identifying the optimal single-photon and two-photon detunings, should lead to improved performance of the quantum memory.