Knob of adjusting transient optical switching by an outer magnetic field in a V-type degenerate medium

Abstract

Abstract Magnetic field plays an important role in studying the transient response because the transition probabilities of degenerate energy levels depend on the external field. The application of an external magnetic field is of particular interest, as the magnetic field is readily available and more flexible to control than an additional laser field, which is an essential consideration in our paper. In this work, we propose a simple model for managing the transient absorption and dispersion properties in a degenerate two-level atomic medium under both transparency and absorption regimes in the presence of spontaneously generated coherence (SGC), an incoherent pumping field, and an external magnetic field. We show that a magnetic field can be utilized as a ‘knob’ to swap the transient absorption and dispersion properties of the system in both transparency and absorption regimes. The magnetic field not only aids in creating transparency and absorption regimes but is also helpful in controlling the system operating at different frequency regions for the probe field without changing the frequency of the coupling field; SGC is introduced to enhance the laser phase dependence of the atomic optical properties, while the incoherent pumping field plays a role in enhancing the effects of SGC and relative phase on the atomic optical properties. The influences of SGC, relative phase, and incoherent pumping rate on transient response are also considered to improve the stability of transient absorption and dispersion properties. Moreover, the essential time required for swapping between subluminal and superluminal light propagation is also provided. The proposed model shows that the system can be used as an ultrafast optical switch, which, in practice, may enable control over switching rates in quantum storage and information-processing devices.