Controllable optical switching in a closed-loop three-level lambda system

Abstract

We propose a model for optical switching in a closed-loop three-level lambda atomic system excited by two optical fields, coupling and probe lights, and by a microwave-driven field. A set of coupled Maxwell–Bloch equations for the atom-field system is numerically solved with a combination of the Runge–Kutta and finite difference techniques. It is shown that the transmitted probe light can be switched to a nearly square pulse train by switching the relative phase of the interacting fields or by switching the intensity of the microwave field. Furthermore, the switching mode between the probe field and relative phase can be anti-synchronous or synchronous, depending on the relative phase being modulated to π/2 and 3π/2 or π and 2π, respectively. Also, the efficiency and the switching rate can be controlled by the microwave field, the relative phase and the intensity of the coupling field. Such a controllable optical switching model can be applied in the design of optical switching and amplification devices working at low light intensities.