Gradient echo memory in a tripod-like dense atomic medium

T. V. Smirnova, Olga M. Fedotova, Oleg Kh Khasanov

A. S. Losev, T. Yu. Golubeva, Yu. M. Golubev

F. Carreño, M. A. Antón

白洪贵 BAI Hong-gui, 黄震 HUANG Zhen, 王明峰 WANG Ming-feng +2 more

Xiwen Zhang

Gradient echo memory (GEM) stores and retrieves photon wave packet in forward direction with high efficiency and fidelity using photon-echo mechanism. It is an important technique for quantum memory applications. By breaking the continuity of the gradient absorption structure, the scheme becomes gradient frequency comb (GFC), which is a hybrid of GEM and atomic frequency comb (AFC). To elucidate the non-trivial field-atom evolution of gradient echo, we derive its exact analytical solution in a medium of arbitrary optical thickness subjecting to any linear gradient of transition frequency, and discuss its physical processes. Based on this solution, we further suggest and analysis two types of GFC, one with stepwise gradient and the other with discontinuous gradient.

James Clark, Khabat Heshami, Christoph Simon

We present a quantum memory protocol that allows us to store light in ensembles of two-level atoms, e.g., rare-earth-metal ions doped into a crystal, by modulating the refractive index of the host medium of the atoms linearly in time. We show that under certain conditions the resulting dynamics is equivalent to that underlying the gradient echo memory protocol, which relies on a spatial gradient of the atomic resonance frequencies. We discuss the prospects for an experimental implementation.