Chemical oxygen iodine laser
Definition/Scope: Chemical oxygen iodine laser, COIL, is an infrared chemical laser. As the beam is infrared, it cannot be seen with the naked eye. The laser is fed with gaseous chlorine, molecular iodine, and an aqueous mixture of hydrogen peroxide and potassium hydroxide. The aqueous peroxide solution undergoes chemical reaction with chlorine, producing heat, potassium chloride, and oxygen in excited state, with spontaneous lifetime of about 45 minutes. This singlet delta oxygen transfers its energy to the iodine molecules injected to the gas stream; they are nearly resonant with the singlet oxygen, so the energy transfer during the collision of the particles is rapid. The excited iodine then undergoes stimulated emission. The laser operates at relatively low gas pressures, but the gas flow has to be nearing the speed of sound at the reaction time; even supersonic flow designs are described. The low pressure and fast flow make removal of heat from the lasing medium easy, in comparison with high-power solid-state lasers.
Broader Terms:airborne laser
Narrower Terms:laser beam
Related Terms:Defensive operation