The metal end plates of a laser device are provided with relatively large annular hub portions extending outwardly from the laser envelope. Glass mirror blocks are used, each having a small area of a reflective coating in the center of one surface of the block. To bond the block to an end plate of the laser device, the mirror is aligned substantially on the axis of the hub and rf energy is used to heat the end of the hub to a sufficiently high temperature to seal it to the glass. The hub is brought into contact with the glass surface of the mirror block and a seal is made without damage to the mirror coating.
A gas laser is disclosed, in which one end surface of a plasma tube of a gas laser envelope is worked to be perpendicular to the axis of the plasma tube, a cap covers a mirror and the end surface of the plasma tube so as to make the mirror abut against the worked end surface, the cap is fixed at its open end to the plasma tube by frit material, and a bore is formed through the plasma tube which is covered by the cap.
