CAVITY Russian patent published in 1998 - IPC

FIELD: laser engineering; carbon dioxide lasers. SUBSTANCE: cavity has two cofocal mirrors 3, 4 with mirror-surface aperture whose size equals that of focal distribution central maximum obtained when focusing parallel beam passed through this aperture by concave mirror 2 closest to output mirror 3, 4, as well as double-face angle reflectors 7-10 installed so that each concave mirror 1 or 2 is against one of faces of other angle reflector 7 or 9 whose edge is oriented perpendicular to that of first angle reflector 8 or 10; concave mirrors 1 and 2 as well as output mirror 3, 4 are mounted on common base. Square aperture is made in output mirror 3 for rectangular region of active medium 11 and its mirror surface is made as part of surface of four-face prism 5. Round aperture is provided in output mirror 4 for round region of active medium 12, 13 and its mirror surface is made in the form of toric surface 6. Laser beam is originated in active medium 11-13 between concave mirrors 1, 2 and reflected from both faces of each angle reflector, then it passes via aperture of output mirror 3, 4 wherein spatial filtration takes place. Beam incident on output mirror 3, 4 is brought out of cavity. This cavity is most useful for carbon dioxide lasers with small volume of active media and high gain, such as with active media in tubes pumped by pulsed gaseous discharge. EFFECT: reduced response to mirror maladjustment, provision or generating high-power, single-mode, steady laser beam with diffraction divergence and linear or round polarization. 3 cl, 4 dwg