Abstract

Observations are reported of a sinusoidal oscillation of the direction of operation of a cw-pumped ring dye laser. The dye laser cavity contains two solid glass etalons and a prism but not a unidirectional device. The etalons are chosen such that the laser operates in two longitudinal modes separated by 10–30 GHz. In these conditions the laser breaks into self-oscillation in which the total amplitude and spectrum of the output of the laser is constant, but the amplitudes of the clockwise and counterclockwise propagating components of the field are each 100% amplitude modulated. The frequency of the modulation can be varied from 10 to 300 kHz by tilting the etalons but is essentially independent of the pumping intensity. The observations are related to a theory of mode competition in the dye jet and to other observations of instabilities in homogeneously broadened lasers.

© 1985 Optical Society of America