Optical analysis of laser systems using interferometry

Previous methods of predicting focal spot parameters such as the Strehl ratio and encircled energy of large laser systems like the Los Alamos fusion CO(2) lasers involved the digitization of interference patterns of the optical components and propagation of the complex amplitude and phase of the wave front throughout the system. In the new approach described in this paper, the computational procedure has been extended to produce computer plots of the final emerging wave front. This enables direct comparison with the experimentally produced wave front of the total system and opens the way for optical analysis, design, and possible optimization of laser systems, especially CO(2) laser systems. The computational procedure and the Twyman-Green and Smartt IR interferometers constructed to verify this approach are described. The implications of the results are discussed.