TIME AVERAGING OF IRREGULAR SPATIOTEMPORAL PATTERNS OF A LARGE APERTURE LASER IN TRANSITORY REGIME

Abstract

By means of a new experimental technique, we measure quasi-intantaneous transverse intensity patterns in the gain-switch peak of a transversely excited atmospheric CO 2 laser with large aperture. The patterns recorded with a 2 ns resolution show a completely irregular spatiotemporal behavior, but when the exposure time of the measurements increases, boundary-determined ordered structures can be observed. As a quantification of this averaging process, the contrast of the intensity distributions decreases as the time integration grows. The results are numerically reproduced by integration of the full Maxwell–Bloch equations.