Nd:YVO4 amplifier for ultrafast low-power lasers.

An Nd:YVO4 amplifier consisting of two modules end pumped at 808 nm at 30 W total absorbed power has been designed for efficient, diffraction-limited amplification of ultrafast pulses from low-power seeders. We investigated amplification with a 50 mW, 7 ps Nd:YVO4 oscillator, a 2 mW, 15 ps Yb fiber laser, and a 30 mW, 300 fs Nd:glass laser. Output power as high as 9.5 W with 8 ps pulses was achieved with the 250 MHz vanadate seeder, whereas the 20 MHz fiber laser was amplified to 6 W. The femtosecond seeder allowed extracting Fourier-limited 4 ps pulses at 7 W output power. To our knowledge, these are the shortest pulses from any Nd:YVO4 laser device with at least 7 W output power. This suggests a novel approach to exploit the gain bandwidth of vanadate amplifiers with high output power levels. Such amplifier technology promises to offer an interesting alternative to high-power thin disk oscillators at few picoseconds duration, as well as to regenerative amplifiers with low-repetition-rate fiber seeders.