Chemical oxygen-iodine laser with atomic iodine generated via fluorine atoms

A chemical method of atomic iodine generation followed by iodine injection into the supersonic nozzle of Chemical Oxygen-Iodine Laser (COIL) was studied experimentally. This method is based on the reaction of gaseous hydrogen iodide (or deuterium iodide) with fluorine atoms formed in a preceding reaction between molecular fluorine and nitrogen oxide. Iodine atoms are generated in specially designed reactors and then injected into the primary gas flow in the COIL cavity. Concentration profiles of atomic iodine along the primary gas flow or perpendicularly to it were measured in dependence on the flow rates of reaction gases. Very high concentrations of atomic iodine (up to 3.2 × 1015 cm−3) were measured in the laser cavity when the primary gas contained no singlet oxygen, O2(1Δg). Yields of atomic iodine related to either F2 or HI were rather high (I/F2 ⩽ 100%, I/HI ⩽ 60%). A small signal gain on the I∗-I laser transition was measured when atomic iodine was injected into the primary gas containing singlet oxygen. The measured gain was lower than the gain estimated from the determined concentration of atomic iodine, temperature, and O2(1Δg) yield measured upstream the iodine admixing. This difference was ascribed to the O2(1Δg) quenching by some product of DI oxidation (probably the radical DO2).