  Quantum memories are a crucial technology for enabling large-scale quantum
networks through synchronisation of probabilistic operations. Such networks
impose strict requirements on quantum memory, such as storage time, retrieval
efficiency, bandwidth, and scalability. On- and off-resonant ladder protocols
on warm atomic vapour platforms are promising candidates, combining efficient
high-bandwidth operation with low-noise on-demand retrieval. However, their
storage time is severely limited by motion-induced dephasing caused by the
broad velocity distribution of atoms comprising the vapour. In this paper, we
demonstrate velocity selective optical pumping to overcome this decoherence
mechanism. This will increase the achievable memory storage time of vapour
memories. This technique can also be used for preparing arbitrarily shaped
absorption profiles, for instance, preparing an atomic frequency comb
absorption feature.
