Selective production of atomic oxygen by laser photolysis as a tool for studying the effect of atomic oxygen in plasma medicine

We propose a method for selectively producing O atoms by the laser photolysis of O-3 as a tool for studying the therapeutic effect of O atoms in plasma medicine. A KrF excimer laser (248 nm) irradiates an O-3/He mixture flowing in a quartz tube to photodissociate O-3, which leads to the production of O atoms. The effluent from the quartz tube nozzle can be applied to a target (cells, bacteria, or an affected part). Simulations show that 500 ppm O atoms can be continuously supplied to a target surface at a distance of 3 mm from the quartz tube nozzle if an O-3(2000 ppm)/He mixture is used. The effluent contains only O, O-3, and O-2(a(1)Delta(g)), and does not contain other types of reactive species in contrast to a plasma. Therefore, it can be used to examine the therapeutic effects of O atoms in isolation. Part of the simulation results are experimentally verified by irradiating an O-3/He mixture with a KrF excimer laser.