Compact, diode-side-pumped Nd3+:YLiF4 laser at 1053 nm with 45% efficiency and diffraction- limited quality by mode...

We demonstrate what we believe to be the highest efficiency obtained to date in a transversely diode-pumped Nd3+:YLiF4 slab laser operating at 1053 nm. The compact 11-cm-long laser cavity configuration is based on total internal reflection of the intracavity beam at the pump facet of the gain crystal to improve the overlap with the pump radiation. Multimode operation with 9.5 W of output power and an efficiency of 45% is obtained for 21 W of pump power in a single-pass configuration. Using a second pass through the crystal and a new mode-controlling technique, the beam quality is improved to the diffraction limit with 6.9 W of output power and 33% of optical-to-optical efficiency.