Novel unstable resonators

In recent years, a laser resonators with the high brightness output beam has been the most preferable for many applications such as remote sensing, optical instrumentation, material processing, and so on. One of the key issues to achieve high brightness operation is in design considerations of the laser resonator geometry matched to a specific laser medium including gain distribution, medium uniformity. In the paper, we report the theoretical analysis and the experimental investigations of a transversely excited atmospheric pressure (TEA) CO/sub 2/ laser and a chemically pumped oxygen-iodine laser (COIL) with newly proposed unstable resonators comparing them with the conventional unstable resonator laser.