A tube for a slab laser comprising: a first elongated electrode comprising a first electrode inner surface; a second elongated electrode comprising a second electrode inner surface, wherein the first electrode is separated, in a first transverse direction (x), from the second electrode thereby defining a gap region extending in a longitudinal direction (z) and having a gap thickness between the first electrode inner surface and the second electrode inner surface; a discharge region that is disposed within a central portion of the gap region; a first and a second elongated baffle member (204a, 204b), each comprising a respective elongated central channel (209a, 209b) formed in an inner surface thereof; wherein the first and second elongated baffle members (204a, 204b) are disposed in the gap region along a first and a second longitudinal edge portion, respectively, of the first and the second electrode (203a, 203b), respectively; and wherein the first and second elongated baffle members (204a, 204b) are disposed with their inner surfaces (206a, 206b) facing the gap region such that the inner surface of the first electrode, second electrode, first baffle member, and second baffle member cooperate to surround the gap region; wherein the elongated central channels (209a, 209b) of the baffle members serve to extend the gap region in a second transverse direction (y) by a depth of the elongated central channels thereby defining stand-off regions (210a, 210b) in the channels that extend along the length of the baffle members in the longitudinal direction (z), wherein the stand-off regions (210a, 210b) do not support a gas discharge and are disposed between outer edges of the discharge region and the inner surfaces (206a, 206b) of the elongated baffle members (204a, 204b); and characterized in that each elongated baffle member (204a, 204b) comprises a plurality of rectangular members (205a, 205b) interconnected, in the longitudinal direction (z), by a plurality of elongated bridge members, and wherein the elongated central channel (209a, 209b) of each baffle member (204a, 204b) runs along the length of an inner surface of the rectangular members (205a, 205b) and the elongated bridge members. a first elongated electrode comprising a first electrode inner surface; a second elongated electrode comprising a second electrode inner surface, wherein the first electrode is separated, in a first transverse direction (x), from the second electrode thereby defining a gap region extending in a longitudinal direction (z) and having a gap thickness between the first electrode inner surface and the second electrode inner surface; a discharge region that is disposed within a central portion of the gap region; a first and a second elongated baffle member (204a, 204b), each comprising a respective elongated central channel (209a, 209b) formed in an inner surface thereof; wherein the first and second elongated baffle members (204a, 204b) are disposed in the gap region along a first and a second longitudinal edge portion, respectively, of the first and the second electrode (203a, 203b), respectively; and wherein the first and second elongated baffle members (204a, 204b) are disposed with their inner surfaces (206a, 206b) facing the gap region such that the inner surface of the first electrode, second electrode, first baffle member, and second baffle member cooperate to surround the gap region; wherein the elongated central channels (209a, 209b) of the baffle members serve to extend the gap region in a second transverse direction (y) by a depth of the elongated central channels thereby defining stand-off regions (210a, 210b) in the channels that extend along the length of the baffle members in the longitudinal direction (z), wherein the stand-off regions (210a, 210b) do not support a gas discharge and are disposed between outer edges of the discharge region and the inner surfaces (206a, 206b) of the elongated baffle members (204a, 204b); and characterized in that each elongated baffle member (204a, 204b) comprises a plurality of rectangular members (205a, 205b) interconnected, in the longitudinal direction (z), by a plurality of elongated bridge members, and wherein the elongated central channel (209a, 209b) of each baffle member (204a, 204b) runs along the length of an inner surface of the rectangular members (205a, 205b) and the elongated bridge members.