“…For example, this is the case for QM based on slow light [ 15 , 16 ]. The cavity-assisted photon echo QM, often called impedance-matched QM [ 11 , 12 ], has been demonstrated in a number of experiments on AFC and ROSE protocols [ 17 , 18 , 19 , 20 , 21 ], which show the possibility of implementing high efficiency, currently achieving up to . Moreover, the impedance-matched approach significantly facilitates the requirements to the optical density of resonant transition and, consequently, expands the practical possibilities in the implementation of existing QM protocols, which has become especially important for the AFC protocol [ 19 , 20 , 22 ].…”