Laser-induced dispersion in a three-level system

Abstract

A theoretical calculation of the polarization changes of a weak probe laser beam as it traverses a strongly pumped gaseous atomic medium is presented. The medium is chosen to be a three-level cascade (J = 0–J = 1–J = 0) system. The polarization of the probe changes from linear to elliptical owing to the asymmetrical population transfer induced by a strong, circularly polarized pumping laser beam. We study this phenomenon as a function of laser intensities, laser detunings, and the relaxation parameters of the medium. We compare the predictions of the theory with results obtained from experimental studies of the neon 1s4(J = 1)–2p4(J = 2)–3s2(J = 1) system.