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 Δ 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.