Interaction of ultraviolet laser radiation with a xecl laser

A significant enhancement (up to 30%) in the output pulse energy of a XeCl laser (l = 308 nm) is observed when ultraviolet-laser radiation at 193, 248, or 351 nm is injected into the XeCl resonator before the emission of the 308-nm pulse. In each case, it appears that the enhancement hinges on the presence of impurity molecules (e.g., hydrocarbons, N₂, O₂) in the XeCl-laser-gas mixture. For l_injectrd= 193 and 248 nm, the external radiation appears to photoionize the impurity directly, whereas, at 351 nm, the impurity is photoexcited and subsequently ionized by the discharge. Strong absorption of 248-nm radiation by the XeCl active medium is observed during and following the XeCl discharge-an effect that is also attributed to impurities.