208-W TEM_00 operation of a diode-pumped Nd:YAG rod laser

208-W average-power ${\mathrm{TEM}}_{00}$-mode operation from a diode-pumped Nd:YAG rod laser was demonstrated. The side-pumping method of generating a high-gain aberration-free rod, the bifocusing-compensation technique with two identically pumped rods, and a suitable choice of beam spot size were employed in the design of this laser. At the maximum pump power of 1.1 kW the fundamental transverse-mode operation $\left(M^2<1.1\right)$ was characterized by 7.6% electrical efficiency. The extraction efficiency was almost 60% of full multimode operation. Stable operation was obtained within a pump-power range of 15% of the maximum pump power.