Impossibility of faithfully storing single photons with the three-pulse photon echo

Abstract

The three-pulse photon echo is a well-known technique to store intense light pulses in an inhomogeneously broadened atomic ensemble. This protocol is attractive because it is relatively simple and it is well suited for the storage of multiple temporal modes. Furthermore, it offers very long storage times, greater than the phase relaxation time. Here, we consider the three-pulse photon echo in both two-and three-level systems as a potential technique for the storage of light at the single-photon level. By explicit calculations, we show that the ratio between the echo signal corresponding to a single-photon input and the noise is smaller than one. This severely limits the achievable fidelity of the quantum state storage, making the three-pulse photon echo unsuitable for single-photon quantum memory.

Coherent control of collective atom phase for ultralong, inversion-free photon echoes

“…Thus, the three-pulse photon echo E1 in Figs. 1(a) and 1(b) becomes absorptive (or negative) in coherence, where stimulated emission (as a major noise factor to quantum memories [17]) by E1 must be quenched. However, the coherent absorption by E1 may alter the quantum fidelity of E2.…”

Collision-induced photon echo at the transition0↔1in ytterbium vapor: Direct proof of depolarizing collision anisotropy

“…Photon echo generated by shaped femtosecond pulses of tunable radiation is one of the most promising tools for the investigation of ultrafast relaxation in condensed media [11]. Photon-echo applications for quantum memory [12,13] and for echo-based optical processors [14,15] seem to be very topical.…”

Control of Photon Storage Time in Photon Echoes using a Deshelving Process

“…Even in single photon-based quantum memory protocols, the spontaneous emission decay-caused quantum noise can be practically removed if an ultrashort pulse is used in a pencil-like geometry, where the pulse duration is still confined by optical inhomogenous width of the optical medium. Although Swiss and Calgary groups jointly criticised that photon echoes cannot be used for quantum memories due to the spontaneous emission noise, it fails with practical conditions in a rare-earth doped solids (Sangouard, N. et al, 2010). In a rare-earth Pr 3+ (0.05 at.…”