Abstract

Since Karras et al. published a paper on the observation of optical cooperative emissions from copper vapor,¹ no other convincing experimental evidence has been reported on this puzzling phenomenon. We reported an observation of a similar behavior of the stimulated emission from the copper-vapor laser in the context of Dicke superradiance.² Subsequently we have carried out a detailed experimental investigation on this pulsing phenomenon in a transverse-discharge copper-vapor laser system. By means of a precision spectral analysis we can identify two principal mechanisms which are responsible for the multiple-pulsing phenomenon in a high-gain condition:

(1) the superimposition of a few pulses corresponding to different regions of the spectrum of the laser line, and

(2) superradiant ringing due to the coherent collective effect. The conditions in which one or the other of the two mechanisms is manifested are subtle and are not completely understood as yet. But the characteristics of the optical pulses resulting from each mechanism are quite distinct. We describe the difference between the two mechanisms and present the experimental results that exhibit an interesting spectral behavior of the laser pulses in each case.

© 1986 Optical Society of America