An edge-pumped ytterbium:YAG slab laser and phased array resonator

Solid-state lasers with high average powers are needed for applications ranging from gravitational wave detection, remote sensing and particle accelerators to cutting and welding. Obtaining good beam quality from these high power lasers is challenging due to thermal distortions of the gain medium. This thesis presents modeling and experimental results on a laser crystal and resonator design that permits average power scaling. The edge-pumped zigzag slab configuration eliminates the distortions to first order, is simple to implement and allows the use of quasi three-level laser media such as Yb:YAG. Results are presented on a testbed Yb:YAG edge-pumped slab laser that produced 45 W of output power at 28% slope efficiency. Models based on the performance of this testbed laser predict operation up to 100 kW should be possible.; Extraction of a high brightness laser mode from the edge-pumped slab is complicated by the large aspect ratio of the slab aperture. One solution is to use a linear array of TEM₀₀ beams across the width of the slab. Six beams were phase-locked together to produce a far field intensity that was 2.3 times higher than the incoherent beams. The beams were coupled by diffraction from a lithographically defined grating on a cavity mirror. This passive phase-locking technique was stable against changes in pump power, vibrations and cavity mirror alignment.