Stationary light pulses in ultra cold atomic gasses

We present experimental evidence that light storage, i.e. the controlled release of a light pulse by an atomic sample dependent on the past presence of a writing pulse, is not restricted to small group velocity media but can also occur in a negative group velocity medium. A simple physical picture applicable to both cases and previous light storage experiments is discussed.

Quantum memories, devices that can store and retrieve photonic quantum states on demand, are essential components for scalable quantum technologies. It is desirable to push the memory towards the broadband regime in order to increase the data rate. Here, we present a theoretical and experimental study on the broadband optical memory based on electromagnetically-induced-transparency (EIT) protocol. We first provide a theoretical analysis on the issues and requirements to achie...

We analyze the storage and retrieval of intense-broadband pulses with the added effects of Doppler broadening and detuning in a $\Lambda$ configuration. We compute analytical solutions via the inverse scattering technique and show how the signal field is transferred to a spin-wave in the atomic medium and later retrieved by the interaction of a control pulse. Due to the intensity of the pulses, the pulse area (as defined for self-induced transparency) plays a key role in the ...

We provide an exact analytic description of decelerating, stopping and re-accelerating optical solitons in atomic media. By virtue of this solution we describe in detail how spatially localized optical memory bits can be written down, read and moved along the atomic medium in a prescribed manner. Dynamical control over the solitons is realized via a background laser field whose intensity controls the velocity of the slow light in a similar way as in the linear theory of elect...

Ultracold atoms confined by engineered magnetic or optical potentials are ideal systems for studying phenomena otherwise difficult to realize or probe in the solid state because their atomic interaction strength, number of species, density, and geometry can be independently controlled. This review focuses on quantum transport phenomena in atomic gases that mirror and oftentimes either better elucidate or show fundamental differences with those observed in mesoscopic and nanos...

Quantum optics with quantum gases represents a new field, where the quantum nature of both light and ultracold matter plays equally important role. Only very recently this ultimate quantum limit of light-matter interaction became feasible experimentally. In traditional quantum optics, the cold atoms are considered classically, whereas, in quantum atom optics, the light is used as an essentially classical axillary tool. On the one hand, the quantization of optical trapping pot...

In this chapter, we will describe the storage and retrieval of quantum light (heralded single photons and entangled photons) in atomic ensembles in a solid state environment. We will consider ensembles of rare-earth ions embedded in dielectric crystals. We will describe the methods used to create quantum light spectrally compatible with the narrow atomic transitions, as well as possible protocols based on dipole rephasing that can be used to reversibly map the quantum light o...

We propose a quantum memory based on the pre-created long-lived macroscopic quantum coherence. It is shown that the proposed approach provides new physical properties and methods for retrieval of the signal light fields and improvement of the basic parameters of quantum memory. We demonstrate how the pre-created coherence can enable quantum storage with low quantum noise, programmable and on demand retrieval of signal light fields in atomic ensembles with natural inhomogeneou...

Photons are excellent information carriers but normally pass through each other without consequence. Engineered interactions between photons would enable applications from quantum information processing to simulation of condensed matter systems. Using an ensemble of cold atoms strongly coupled to an optical cavity, we demonstrate experimentally that the transmission of light through a medium may be controlled with few photons and even by the electromagnetic vacuum field. The ...

We show how the application of a coupling field connecting the two lower metastable states of a Lambda system facilitates stoppage of light in a coheren tly driven Doppler broadened atomic medium via electromagnetic induced transparency