A linearly polarizing internal mirror type gas laser tube comprises a channel-shaped holder pair for axially compressively holding a Brewster plate in a hollow cylindrical space surrounded by an inside surface of a pipe. Each holder comprises a side wall pair and a connecting wall connecting the side wall pair. Each side wall has a pair of protrusions having a common axial end plane that provides the Brewster angle. The holders are brought into contact with the Brewster plate with the protrusions made to contact with corner portions of the plate. The side walls may have free ends spaced apart from the pipe inside surface. Alternatively, the side walls of at least one of the holders may have outwardly bent portions having free ends brought into contact with the pipe inside surface. It is readily possible to press shape the holders at low costs from a metal sheet.

A gas laser, includes: a tube having two ends to be filled with gas; and a plate-shaped window hermetically sealing at least one of the ends of the tube; the window including a carrier plate and a layer coating the inside of the carrier plate; the tube being formed of a first material with a first thermal coefficient of expansion (H.sub.1) at least in vicinity of the one end thereof having the window; the layer being formed of a second material with a second thermal coefficient of expansion (H.sub.2); the carrier plate being formed of a third material with a third thermal coefficient of expansion (H.sub.3); the first and second materials being unadapted to each other; and the third material being thermally matched to the first material.

Laser device comprising a tube for gaseous or vaporous laser material, which tube is sealed at both ends by a window consisting of a plate of radiation-transmissive material. Each window plate rests directly on the associated end face of the tube and is held against this end face by a retaining frame surrounding the window plate and secured to the end face of the tube. The retaining frame has its surface remote from the end face provided with a flange extending inwardly to overlie the periphery of the window plate and has its surface facing the end face provided with a recess located at its inner edge surrounding the side edge of the window plate. An O-ring is received in the recess.

A gas laser tube assembly includes a gas laser tube having ends, optical elements each vacuum-tightly closing off a respective end of the gas laser tube, each of the optical elements including a washer-shaped ceramic flange and a terminating plate being transparent to laser radiation and thermally matched to the ceramic flange, the ceramic flange having an outer rim joined to the gas laser tube and a central beam passage opening formed therein, and the terminating plate having two base surfaces, and glass solder connecting the terminating plate to the ceramic flange with the terminating plate covering the beam passage opening and projecting beyond the ceramic flange with at least one of the base surfaces thereof and a method of manufacturing the same.

An adjustable optical element mount having a pair of ball elements, respectively attached to a base and optical element, within a pair of sockets positioned at opposite ends of a spindle which supports a screw actuated cam element positioned within the spindle and between a pair of plungers which simultaneously engage and clamp the both ball elements against the sockets in response to rotation of the screw to hold the ball elements in a desired position.