Parametric study of the Ben-Gurion University efficient chemical oxygen-iodine laser

We report on a detailed parametric study of an extremely efficient supersonic chemical oxygen-iodine laser (COIL) with supersonic mixing of iodine and oxygen. Output power exceeding 0.5 kW with chemical efficiency of similar to33% was obtained in a 5 cm gain length for Cl-2 flow rate of 17 mmole/s. 33% efficiency is the highest reported chemical efficiency of any supersonic COIL. Comparison between different mixing schemes shows that for supersonic mixing the output power and chemical efficiency are about 20% higher than for transonic mixing scheme. The optimal conditions for the efficient operation are investigated. Diagnostic measurements of the small-signal gain shows that the value of the gain for the supersonic mixing scheme corresponding to the maximum efficiency is about 0.75%/cm, about 1.5 times larger than for transonic mixing scheme. Studies of different supersonic mixing schemes show that to achieve further power increase the injection location should be moved downstream.