Stopped Light and Image Storage by Electromagnetically Induced Transparency up to the Regime of One Minute

Abstract

The maximal storage duration is an important benchmark for memories. In quantized media, storage times are typically limited due to stochastic interactions with the environment. Also, optical memories based on electromagnetically induced transparency (EIT) suffer strongly from such decoherent effects. External magnetic control fields may reduce decoherence and increase EIT storage times considerably but also lead to complicated multilevel structures. These are hard to prepare perfectly in order to push storage times toward the theoretical limit, i.e., the population lifetime T(1). We present a self-learning evolutionary strategy to efficiently drive an EIT-based memory. By combination of the self-learning loop for optimized optical preparation and improved dynamical decoupling, we extend EIT storage times in a doped solid above 40 s. Moreover, we demonstrate storage of images by EIT for 1 min. These ultralong storage times set a new benchmark for EIT-based memories. The concepts are also applicable to other storage protocols.

Slow, Stored and Stationary Light

“…In the so-called Mott insulating phase atoms are particularly protected from perturbations such as collisions and diffusion, which leads to the prolonged storage duration. The current record for storage times is 1 min [31]. It has been obtained in doped glasses, where impurity atoms behave almost like free atoms in a vapor with the advantage that they do not move as in the Mott insulating state discussed above, and the atomic density is higher than in a gas.…”

Compact entanglement distillery using realistic quantum memories

“…Several groups are developing high efficiency quantum memories [36][37][38] and memories with very long storage times [39]. Large values for the time-bandwidth product τ have already been demonstrated, exceeding several thousands [40,41], and in some cases achieving values as high as τ ∼ 10 8 [42].…”

Dual atomic interferometer with a tunable point of minimum magnetic sensitivity

“…Coherence times of six hours has been obtained using rare earth doped crystals at a Zero First Order Zeeman (ZEFOZ) point [21]. The effect of environmental fluctuations is further reduced by the use Dynamical Decoupling (DD) [18,21,22]. The residual magnetic field noise can be characterized using a co-magnetometer while the measurement takes place [3,11,23].…”