A gas discharge laser and method of operating same is disclosed which may comprise a gas discharge laser chamber support structure comprising a first support arm attached to a mounting table; a gas discharge laser chamber slideably engaging the first support arm; an first optical element sensitive to chamber vibration positioned at a first end of the laser chamber mounted on the mounting table; the laser chamber support structure being without connection to the first optical element. The apparatus and method may also comprise a second optical element sensitive to chamber vibration positioned at the second end of the laser chamber mounted on the mounting table; the laser chamber support structure being without connection to the second optical element. The first optical element may comprise a line narrowing optical arrangement and the second optical element comprising an output coupler.