Abstract: A molecular fluorine laser system for generating a laser output beam around 157 nm includes a discharge chamber filled with a gas mixture including molecular fluorine and a buffer gas, multiple electrodes within the discharge chamber and connected to a discharge circuit for energizing the gas mixture, and a resonator. The resonator includes at least one optic for selecting a primary line including suppressing a secondary line among multiple characteristic photoemission lines around 157 nm. The same or a different optic, which may be intracavity or alternatively extracavity, may be configured for polarizing the selected line so that the output beam has a polarization of at least substantially 95% when the beam exits the laser system.