Improved light-matter interaction for storage of quantum states of light in a thulium-doped crystal cavity
Jacob H. Davidson, Pascal Lefebvre, Jun Zhang, Daniel Oblak, Wolfgang Tittel
Abstract
We design and implement an atomic frequency comb quantum memory for 793-nm wavelength photons using a monolithic cavity based on a thulium- (Tm-) doped ${\mathrm{Y}}_{3}{\mathrm{Al}}_{5}{\mathrm{O}}_{12}$ crystal. Approximate impedance matching results in the absorption of 90% of input photons and a memory efficiency of $(27.5\ifmmode\pm\else\textpm\fi{}2.7)%$ over a 500-MHz bandwidth. The cavity enhancement leads to a significant improvement over the previous efficiency in Tm-doped crystals using a quantum memory protocol. In turn, this allows us to store and recall quantum states of light in such a memory. Our results demonstrate progress toward efficient and faithful storage of single-photon qubits with a large time-bandwidth product and multimode capacity for quantum networking.