Abstract: An optical system is disclosed for improving the brightness symmetry of a beam emitted from a laser diode where the beam has a large width and a narrow height. The optical system includes a tilt plate for displacing one half of the width of the beam downwardly. A first beam steering prism functions to tilt the remaining, second half of the beam width in a plane parallel to the width dimension so that the second half travels towards the first half. A second beam steering prism is provided to tilt the second half of the beam so that its propagation axis is parallel to the propagation axis of the first half and wherein the second half is stacked above the first half. The optical system functions to improve the brightness symmetry of the beam by a factor of about five. The corrected beam can be used to improve the performance of a solid state laser which is end pumped by a broad area laser diode or a laser diode bar.

Abstract: A new compositional relationship in the starting charge of a crystal growth station (FIG. 1 ) provides homogeneous monocrystalline lithium niobate. A new measurement system (FIG. 2 ) provides Curie point values of significantly greater accuracy then that of conventional measurements. Careful control of the starting charge composition for crystal growth and effective utilization of the measurement system enable the determination of the compositional range of starting charges for producing congruent crystalline production. The composition corresponds to a mol percentage of 48.35.+-..01 to 48.40.+-..01 of Li.sub.2 O and the remainder Nb2.sub.O 5 for producing homogeneous crystal whose solidification fraction of the molten charge exceeds that which was heretofore achievable.

Abstract: A resonator assembly particularly suited for a diode pumped solid state laser is disclosed. The assembly includes a glass planar support plate 20. At least two transparent mirror mounts 26, 28 are bonded to the plate using a UV curable adhesive. The resonator mirros 22, 24 are in turn bonded to the mounts using a similar adhesive. The structure is easy to align and assemble and is low in cost. In addition, the assembly can be formed from materials having a low coefficient of thermal expansion so that the thermal stability is enhanced. Further, the transparent mirror mounts provide enhanced stability while allowing transmission of laser radiation.

Abstract: An improved geometry is disclosed for enhancing the efficiency of second harmonic conversion in a Type II phasematching material. In this approach, the effects of wave vector double refraction are used to compensate for the effects of Poynting vector walk-off. To achieve this goal, the input fundamental beam 32 is arranged to enter the doubling crystal 30 at an oblique angle of incidence. This angle is selected so that the wave vector double refraction angle is equal to the Poynting vector walk-off. In order to maximize doubling efficiency, the axes of the crystal must be oriented so that the optimum phasematching angle coincides with the propagation axis of the refracted fundamental beam travelling in the crystal. The subject invention is particularly suited for use with a KTP crystal in either intracavity doubling or in an external resonant geometry.

Abstract: A ring laser is provided with only two reflecting surfaces to define the cavity. A gain medium is located between the reflecting surfaces. At least one optical interface is located within the cavity and is oriented such that the beam will be deflected by refraction to create a ring path. The angle of incidence of the beam with the interface should be less than Brewster's angle and the surface should have an antireflective coating. The interface can be located on the lasant material, on a non-linear optical material or on a passive optical element. Preferably, the device is arranged to achieve unidirectional and single frequency operation. When the ring is used for intracavity second harmonic generation, the resultant output is amplitude stable because of the avoidance of mode beating. The second harmonic radiation is generated unidirectionally increasing useable output.

Abstract: Translation apparatus for a crystal fiber includes a resilient belt which receives a crystal fiber in pressure engagement. The fiber is supported against the belt by a support member having a grooved surface for receiving the fiber. A floating block is positioned within a loop of the belt and is offset in the loop when the support member and fiber are brought into engagement with the belt.