Abstract

Experimental investigations of optical bistability (OB) for systems with degenerate lower states have up to now relied principally on atomic sodium [1-4]. The study of the influence of lower level coherence effects in OB [5] is greatly aided by the use of a nonlinear medium having a transition with integral electronic angular momentum character. A suitable choice upon which we report here is the 4f⁶ 6s² (⁷F₁) to 4f⁶ 6s6p (⁷F_o^o) 570.68-nm transition in SmI, driven by linearly polarized laser excitation in a near-concentric Fabry-Perot cavity. Unlike the case of the Na J = 1/2 to J = 1/2 D₁ transition, for which polarization asymmetry in switching (PS) develops spontaneously [1-4], for the above transition we find that the symmetry in the polarization is conserved. No polarization differences of σ⁺ with respect to σ⁻ develop in the output from the optical cavity. This behaviour accords with the theoretical expectation [6] that PS is suppressed by transverse optical pumping.

© 1985 Optical Society of America