The Role Of Magnetic Field In Phase Sensitive Electromagnetic Induced Transparency

In this thesis, we study a double-lambda system coupled by two orthogonally linearly polarized laser fields, a probe and a pump. We find the system more phase sensitive when a static (DC) magnetic field is applied.We find that the DC magnetic field, which generates Zeeman splitting of the ground states in the circular basis, becomes an effective coupling field between the ground states in the linear basis. It is demonstrated that the gain and the refractive index of the probe can be controlled by either the magnetic field or the relative phase between the two laser fields. In the pulsed-probe regime, it is possible to switch between fast light and slow light via relative phase manipulation or magnetic field adjustment..More interestingly, when the system reduces to a single-lambda system in cold atom regime, turning on the magnetic field transforms the system from a phase-insensitive process to a phase-sensitive one. This is because the system forms a closed loop with the existence of the magnetic field.This work provides a novel and simple means to manipulate phase sensitive electromagnetically-induced-transparency or four-wave mixing, and could be useful for applications in quantum optics, nonlinear optics and magnetometery based on such systems.