We model the effects of atomic thermal motion on the propagation of a light pulse in an electromagnetically induced transparency medium by introducing a set of effectively temperature-dependent parameters, including the Rabi frequency of the coupling field, optical density and relaxation rate of the ground state coherence, into the governing equations. The validity of this effective theory is verified by the close agreement between the theoretical results and the experimental data.

Encryption is a vital tool of information technology protecting our data in the world with ubiquitous computers. While photons are regarded as ideal information carriers, it is a must to implement such data protection on all-optical storage. However, the intrinsic risk of data breaches in existing schemes of photonic memory was never addressed. We theoretically demonstrate the first protocol using spatially disordered laser fields to encrypt data stored on an optical memory, namely, encrypted photonic memory. Compare with a digital key, a continuous disorder encrypts stored light pulses with a rather long key length against brute-force attacks. To address the broadband storage, we also investigate a novel scheme of disordered echo memory with a high fidelity approaching unity. Our results pave novel ways to encrypt different schemes of photonic memory based on quantum optics and raise the security level of photonic information technology.Comment: 5 pages and 4 figure

Cavity quantum electrodynamics (CQED) has played a central role in demonstrating the fundamental principles of the quantum world, and in particular those of atom-light interactions. Developing fast, dynamical and non-mechanical control over a CQED system is particularly desirable for controlling atomic dynamics and building future quantum networks at high speed. However conventional mirrors do not allow for such flexible and fast controls over their coupling to intracavity atoms mediated by photons. Here we theoretically investigate a novel all-optical CQED system composed of a binary Bose-Einstein condensate (BEC) sandwiched by two atomic ensembles. The highly tunable atomic dispersion of the CQED system enables the medium to act as a versatile, all-optically controlled atomic mirror that can be employed to manipulate the vacuum-induced diffraction of matter-wave superradiance. Our study illustrates a innovative all-optical element of atomtroics and sheds new light on controlling light-matter interactions.

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