Abstract: An annular ring resonator which employs relay imaging to reduce crosstalk caused by diffusion which occurs between biconic mirrors 30 and 31 in the resonator.

Abstract: An improvement for an off-axis, unstable, ring-resonator laser wherein the feedback beam 16 is rotated 90.degree. by a 90.degree. rotator 18 and is then magnified by magnification means 22 so that the dimensions of the rotated, magnified beam 24 will correspond to the dimensions of the gain medium 12 of the laser.

Abstract: A system for phase-matching arrayed telescopes by means of a corner-cube-bridge metering rod comprises a plurality of arrayed telescopes 10, a source 30 of laser light reflecting means 32,40,42,44,46 for directing the laser beam through the telescopes 10, one of the reflecting means being a beam splitter 42 for directing a different portion of the laser beam through each telescope 10, an absolute distance interferometer (ADI) 38, boresighting means including a hole plate 32, a focusing lens 34 and an alignment sensor 36, and a metering rod 16 carrying four corner-reflector cubes, two near each end. The ADI beam is aligned with the laser source beam by using the boresighting means. The metering rod 16 is mounted between two adjacent telescopes 10 so that two adjacent corner cubes reflect the beam coming through one telescope and the other two adjacent cubes reflect the beam coming through the other telescope.

Abstract: An optical resonator having an annular cylindrical gain region for use in a chemical laser or the like in which two ring-shaped mirrors having substantially conical reflecting surfaces are spaced apart along a common axis of revolution of the respective conical surfaces. A central conical mirror reflects incident light directed along said axis radially outwardly to the reflecting surface of a first one of the ring-shaped mirrors. The radial light rays are reflected by the first ring mirror to the second ring mirror within an annular cylindrical volume concentric with said common axis and forming a gain region. Light rays impinging on the second ring mirror are reflected to diametrically opposite points on the same conical mirror surfaces and back to the first ring mirror through the same annular cylindrical volume. The return rays are then reflected by the conical mirror surface of the first ring mirror back to the central conical mirror.