Thermal effects such as thermal lens and thermally induced birefringence are critical in solid-state lasers, degrading the beam quality and preventing higher-power operations. The composite lasers, which consist of laser-ion-doped and undoped materials, have been successful in supressing those thermal effects because the heat generated in the doped region can be effectively removed into the undoped segment. Composite structures have been fabricated mainly with the diffusion bonding [1], and a hybrid composite of a doped single crystal and undoped ceramics has been also recently reported [2]. However, it is difficult for the diffusion-bonding technique to bond materials with different thermal-expansion coefficients, and the undoped ceramics are limited to isotropic materials.