To improve the thermal performance of Nd:YAG lasers, a Nd:YAG laser crystal is bonded on a SiC wafer by atomic diffusion bonding (ADB) via a Mo/Au nano-interlayer at room temperature. In addition, a two-dimensional model of the Nd:YAG-SiC with a Mo/Au nano-interlayer is developed to investigate the thermal aberration and temperature distribution inside the Nd:YAG. The result shows that the bonded Nd:YAG-SiC exhibits an extremely low voidage, along with a 106-nm-thick metal interlayer. The simulation reveals that the Nd:YAG-SiC has a maximum temperature of 393.3 K with a reduction of 28.5 K and a less thermal aberration near the axis compared to the Nd:YAG-CuW at a pump power density of 5 kW/cm2.