Solid-state Raman quantum memory in whispering gallery mode resonators: signal-to-noise ratio

Abstract

The possibility of implementation of optical quantum memory via off-resonant Raman absorption and emission of single-photon pulses in rare-earth-ion-doped crystals is theoretically analysed taking into account signal-to-noise ratio at the output of the memory device. The crystal 143Nd3+:Y7LiF4 is considered as an example. It is shown that the signal-to-noise ratio can exceed unity for single-photon input pulses provided that storage and retrieval of them is performed in the doped crystals forming a microcavity such as whispering gallery mode resonator.