Abstract

In the recent few years, some researchers have paid a great interest in RF discharge excited waveguide array CO₂ lasers for their advantages over single channel structure lasers. A variety of waveguide array coupling techniques and structures have been proposed and reported. In this paper, we shall present the results of experimental studies of a new type of optical waveguide resonator that is combined with an RF discharge excited large aspect ratio waveguide to produce a far field highly suppressed supermode output beam. This type of waveguide optical resonator laser has demonstrated the characteristics of a linear waveguide array CO₂ laser. At near field, the intensity distribution of the output beam manifests itself as many horizontally lined separate beam spots; at far field, the intensity distribution of the output beam shows horizontally a highly spatially suppressed single peak. Experimental study has revealed that for the supermode beam, the surface curvature of the waveguide optical resonator mirrors plays a very important role, and as the length of the waveguide optical resonator varies, the far field intensity distribution of the output beam changes periodically. The experimental results have also shown that the aspect ratio of waveguide cross section has less influence on the output beam characteristics of this type of waveguide optical resonators.

© 1994 IEEE