Community Research and Development Information Service - CORDIS


SLICA — Result In Brief

Project ID: 289305
Funded under: FP7-PEOPLE
Country: Germany

The art of taming light

In modern physics, light is regarded as the swiftest thing in the universe. Albert Einstein theorised that light cannot travel faster than 300 million metres per second, but he never said it could not move slower.
The art of taming light
Transparent material like water and glass slow down light slightly. As a result, light rays are bended, allowing prisms to produce spectra and lenses to focus images. Using a distantly related but more powerful effect, researchers working on the EU-funded project SLICA (Stationary light in cold atoms) first slowed down and then stopped light in a medium of cold atoms.

Electromagnetically induced transparency (EIT) is a phenomenon in which a material that does not normally transmit light can be made transparent for a certain range of wavelengths. With the use of counter-propagating laser beams, EIT provided SLICA researchers with a powerful tool to control the propagation of light inside optically driven media.

Specifically, this technique allowed them to slow down light and create stationary light pulses (SLPs) in a medium of cold atoms. In contrast to stored light where no light is present during storage, SLPs allow for the effective stopping of light pulses. The first experimental demonstration of SLPs was achieved more than a decade ago in a hot gas of rubidium atoms.

Unlike in hot media, however, the creation of SLPs in cold media was not straightforward. High-frequency atomic coherences can have a detrimental effect on the transmission of light that is naturally suppressed in hot media. The researchers showed that these effects could be dramatically suppressed by reducing the width of the EIT transparency window below the typical Doppler shifts.

SLICA scientists also demonstrated for the first time the efficient loading of cold atoms into a hollow-core fibre, laying the groundwork for implementing non-linear optics at the few-photon level with SLPs. In such a system, atoms and photons are tightly confined to macroscopic distances, resulting in a strong coupling between light and matter, involving optical non-linearities.

In addition to their fundamental scientific interest, the project team's efforts were stimulated by practical applications of SLPs. Among the many foreseen applications of SLPs is their use in all-optical processing and information storage in computers operating based on quantum effects as well as fibre-optic communications.

SLICA project results have not only pushed the frontiers of EIT-based light propagation manipulation, they also provided a missing link in the control of information carried by light.

Related information


SLICA, stationary light, cold atoms, electromagnetically induced transparency, laser beams
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