Lasing in supersonic chemical oxygen-iodine lasers: recent modeling and comparison with experiment

Simple models are developed, describing the power extraction in chemical oxygen-iodine lasers (COILs) with stable and unstable resonators. For stable resonators the model is applied to the ejector high pressure COIL and the results are compared with the experimental data (see also a preceding paper by Rosenwaks et al.). The positive and negative branch unstable resonators with cylindrical mirrors that have been recently used in COILs are studied theoretically using a geometrical optics model. The optical extraction efficiency, spatial distributions of the intracavity radiation intensity in the flow direction and the intensity in the far field are calculated for both kinds of resonators as a function of both the resonator and COIL parameters. The optimal resonator magnifications corresponding to the maximum intensity in the far field are found.