Abstract: A composite slab laser medium provided with a non-doped layer containing substantially no laser active materials and a first and second doped layers provided at both sides of the non-doped layer, respectively, in such a manner to hold the non-doped layer, each of which contains a laser active material. In this composite slab laser, a first surface of the first doped layer and a second surface of the second doped layer are in contact with the outside of the composite slab laser medium and are parallel with each other. Further, a laser oscillation or an optical amplification is performed by extracting a laser beam which travels in a zig-zag path undergoing total internal reflection at the first and second surfaces employed as alternate reflecting surfaces within the composite slab laser medium. Moreover, layers made of laser glass containing Nd.sub.2 O.sub.3 of from 3 to 9% by weight is employed as the doped layers. Furthermore, a total of the thicknesses of the first and second doped layers is of from 0.

Abstract: In a solid-state laser device having a laser medium, a reflector member has first and second curved portions surrounding first and second reflector axes, respectively, and an extension portion extended from the first and the second curved portions towards a principal surface of the laser medium for defining an internal space together with the curved portions. Within the internal space, first and second lamps are disposed farther from the principal surface than the first and the second reflector axes, respectively, with first and second lamp axes of the first and the second lamps juxtaposed to the reflector axes and an optical axis of the laser medium. Each curved portion has an arcuate internal surface which forms a partially circular cylinder having a center axis as the reflector axis. Alternatively, the arcuate internal surface of each curved portion forms a partially elliptic cylinder having a symmetry axis as the reflector axis and an outside focal line with which the lamp axis substantially coincides.