Diode-end-pumped double Nd:YLF slab laser with high energy, short pulse width, and diffraction-limited quality

We have developed a novel electro-optic Q-switched diode-end-pumped solid slab laser that combines high energy, short pulse width, high repetition rates, and diffraction-limited beam quality. With two partially end-pumped Nd:YLF slabs and a 100 mm long off-axis positive branch stable-unstable oscillator, 24.2 mJ, 7.1 ns electro-optic Q-switched pulse at 1 kHz repetition rate with a beam quality of M(x)(2)=1.4 and M(y)(2)=1.3 was generated. The peak power reached 3.5 MW. Efficient external second-harmonic generation was achieved by use of lithium triborate with low peak-power intensity.