Abstract

A transverse optical bistability is defined here as a bistability that would not occur with a plane-wave input; it is characterized by pronounced changes in transverse profiles, but not in total transmission.^1-5 In order to use transverse bistabilities to study instabilities of the type first studied by Ikeda⁶ for a ring cavity, one needs a medium response time τ_M less than the round-trip time t_R between the medium and the feedback mirror. Here instabilities are studied experimentally using a short length of sodium vapor and a far-field mirror (Fig. 1).^7,8 This system has advantages over previous^9,10 all-optical passive systems for studying instabilities: its input is cw, permitting the study of slowly evolving waveforms; it has little sensitivity to laser frequency shifts, because it has no cavity; its optical nonlinearity arises from a vapor of one-electron atoms, giving hope for a detailed quantitative comparison of experiments and calculations.

© 1985 Optical Society of America