High-power Nd:YLF master oscillator power amplifier with 15 W single-frequency output at 1053b nm

Summary form only given. Efficient solid-state sources with high power, good beam quality and narrow-linewidth output are required for many applications. Power-scaling of diode-pumped single-frequency solid-state lasers to meet the requirements of these applications has been hindered by strong thermal effects which can degrade beam quality and efficiency, and often make the selection of a single-axial-mode difficult. A further problem is that changes in cavity length due to temperature fluctuations become more pronounced at high pump powers, leading to mode-hopping. The latter problem can, in principle, be eliminated by active stabilisation of the cavity to an external reference cavity, but at considerable increase in complexity and cost. Here we report an efficient diode-end-pumped Nd:YLF master oscillator and power amplifier (MOPA), with >15 W of reliable single-frequency output at 1.053 /spl mu/m, exploiting the weak thermal lensing behaviour on the lower gain /spl sigma/-polarisation to avoid degradation in beam quality, and utilizing a simple technique to suppress axial-mode-hopping in the master oscillator.