Influence of pump bandwidth on the efficiency of side-pumped, double-beam mode-controlled lasers: establishing a new record for Nd:YLiF(4) lasers using VBG.

We analyze the performance of a VBG equipped diode of narrow linewidth in a side-pumped double-beam, mode-controlled resonator and demonstrate power scaling without loss of beam quality by a factor of three, when compared to previous results. 69 W of diffraction-limited laser output power at 1053 nm in a Nd:YLF lasers are demonstrated with slope efficiency of 65% and record optical-to-optical efficiency of 60%.