Grazing-incidence YVO4-Nd:YVO4 composite thin slab laser with low thermo-optic aberrations.

We present a novel grazing-incidence composite thin slab laser (CTSL) with an almost aberration-free gain medium. The laser consists of a 260-microm thin Nd:YVO4 plate that is diffusion bonded to an undoped YVO4 slab. The Nd:YVO4 plate is cooled at just one side, suppressing temperature gradients that would induce wave-front distortions in the laser field. The pump light of a noncollimated diode bar is directly coupled into the undoped YVO4 slab and guided by total internal reflection to the attached Nd:YVO4 plate. Since any pump-beam-shaping optics can be omitted, the laser is simple and compact. We obtained transverse multimode optical output powers of 14 and 9.3 W with M2 < or = 1.3.