Abstract: A hollow member or an envelope 7 housing a laser medium 3 having a reflective coating 31 on one surface thereof, a non-linear optical crystal 4 and an output mirror 5 having a reflective coating 51 on one surface thereof has a thin-walled portion 71 in its center portion. The air-tightly sealed envelope 7 is evacuated through an exhausting pipe 9 and, after sealing the pipe 9, a laser resonator unit 70 is obtained. By arranging a laser diode unit 10 on the reflective coating 31 of the laser medium 3 and integrating it by a connecting member 17, a long life-time, compact solid state laser excited by laser diode is obtained.

Abstract: In a traveling wave tube device of the type comprising a helix which causes a microwave power to interact with an electron beam and a periodic permanent magnet assembly for focusing the electron beam, there are provided a plurality of annular permanent magnets and a plurality of pole pieces which are alternately disposed between input and output member of the microwave. The permanent magnets and pole pieces define annular recesses and a plurality of troidal metal spring rings are disposed in each recess in thermal contact with the permanent magnets and a carbonaceous coating coated on a pumped enclosure containing the helix.