Attenuation, Delay and Noise properties of light slowed by Electromagnetically Induced Transparency

Abstract

Electromagnetically Induced Transparency is an effect that allows light to propagate through an otherwise opaque material. Due to the dispersion properties of the EIT system, it also slows the information carried on the sideband frequencies of a light beam. The effect can also be used to store information in an atomic medium. It was therefore proposed that EIT systems can be applied in optical cicuits, specifically with regard to quantum information processing where it is necessary to delay, or store quantum states of light. Hence it is necessary to understand how EIT systems influence the quantum state of a light beam and whether EIT systems can ever have the potential to delay and store quantum information at the quantum noise limit. ¶ This thesis examines the transfer of an optical signal at the sideband frequencies through an EIT medium. A comprehensive characterisation of an EIT system in terms of delay and signal transmission is performed. This measurement technique provides data on EIT performance over a range of signal frequencies and a range of experimental parameters. Experiments were conducted with both pure Rubidium vapour and Rubidium vapour mixed with a noble gas. ¶ Studies have been made into a new system of measurement that will allow delay, attenuation and added noise spectra to be assessed via a single-shot measurement.