Laser

摘要

1,242,642. Lasers. COMPAGNIE GENERALE D'ELECTRICITE. 11 Feb., 1969 [12 Feb., 1968], No. 7439/69. Heading H1C. In a gas laser in which the active medium is located between resonator mirrors 17, 21, Fig. 2, and a further resonator formed by mirrors 17, 18 and a partially-reflecting plate 9 causes a single mode output to pass through a window 12, the partially-reflecting plate 9 is positioned at the Brewster angle on a block 14 together with mirrors 17, 18, the block being formed with ducts 15, 16 for the laser radiation. The active medium, which may be helium-neon, is contained in a capillary 2 in a tube 1 and is pumped by electrodes 4, 41 housed in tube extensions 3, 31. The end faces 6 of tube 1 are machined to provide spherical surfaces which engage complementary surfaces of cylindrical elements 7, 23 each formed with a duct 10 for the laser radiation. Element 7 carries the plate 9 and block 14, while element 23 supports a piezoelectric transducer 22 carrying the mirror 21. Energization of the transducer electrodes 24, 241 by a feedback circuit comprising a signal generator 27, a data processing circuit 28 and a detector 29, determines the axial position of the mirror regulates the output mode. The tube 1, the elements 7, 23 and the block 14 may be made of fused quartz. In a modification, Fig. 3 (not shown), the feedback circuit is connected to a piezo-electric transducer which regulates the axial position of mirror 18. An alternative arrangement, Fig. 4 (not shown), has the active medium contained in the capillary of a tube both ends of which are sealed by Brewster angle windows, the block 14 used in Fig. 2 being either in contact with or spaced from one window.