Manipulation Of Slow Light In Electromagnetically Induced Transparency Medium

Based on the fundamental theories and techniques of ultraslow light and storing light information in Electromagnetically Induced Transparency (EIT) medium, we theoretically adopt several special control-light intensity profiles: U-, V- and S-type and periodic profile to manipulate slow-light propagation, and investigate the influences of different control-light parameters on slow-light propagation. For a coupling field with a square-well-like spatial variation of the intensity, only probe light at exact resonance w = w₀ can totally pass through the medium. Adjusting the well width z₀ or probe-light frequency to the condition of resonant penetration also permits probe light totally transmit. Increasing the width z₀ or depth of the well can narrow the transparency window. For a triangle spatial variation of the intensity, the interface forms an optical analogue of event horizon, which causes a wave singularity similar to that associated with black holes. For a coupling field with a S -well-like spatial variation of the intensity, only probe light at exact resonance w = w₀ can totally pass through the medium. Increasing the parameter β of δ well can make the transparency window narrower. For a periodically spatial variation of the intensity, a periodically alternating sequence of dielectric domains with high contrast in their refractive index is formed. Hence, a photonic band gap arises depending on the period of intensity. This phenomenon is similar to what happens in photonic crystals, i.e., the well-known light localization effects.