Incoherent pumping and phase control of the high index of refraction without absorption

Abstract

We propose a closed three-level V-type system with an incoherent pumping which achieves a high index of refraction without absorption via spontaneously generated coherence. The system has two near-degenerate excited levels. We derive full analytical formulas for the index of refraction and the gain (absorption) coefficient. We found that the proper choice of the incoherent pumping, the relative phase of the two coherent fields, the Rabi frequencies, the probe detuning and the angle between the two transitions leads to the enhancement of the refractive index without absorption.