LASER RESONATOR Russian patent published in 2007 - IPC H01S3/08 

FIELD: laser engineering.

SUBSTANCE: laser resonator has convex mirror mounted confocal and concave mirror with central opening, which has axis to coincide with concave mirror. Additional mirror is mounted behind concave mirror. Opening is made in convex mirror; opening has center at optical axis of resonator. Surface of opening which opening adjoins reflecting surface of mirror is made in form of toroid; reflecting coating is applied onto toroid surface. Second additional mirror being confocal to first one, is mounted behind convex mirror. Both additional mirrors are made concave; optical axes of mirrors are brought into coincidence with optical axis of resonator. Focus of additional mirrors is disposed in opening of convex mirror in plane of cross-section of minimal diameter. F1/F2>f1/f2 and df1/f2<=D=>dF1/F2, where D is diameter of opening in concave mirror, f1 and f2 are focal lengths of first and second mirrors, F1 and F2 are focal lengths of concave and convex mirrors, d is minimal diameter of opening in convex mirror found from formula of d=2√0,621λxf2, where λ is radiation wavelength.

EFFECT: reduced laser beam intensity divergence angle.

2 dwg