Analysis of lasing in COILs with positive and negative branch unstable resonators using a simple geometrical-optics model

Abstract

A simple geometrical optics model is developed, describing the power extraction in chemical oxygen-iodine lasers with unstable resonators. The positive and negative branch unstable resonators with cylindrical mirrors that were recently used in the COIL are studied. The optical extraction efficiency and intensity spatial distributions in the flow direction for both kinds of resonators are calculated.