640-nm Pr:YLF regenerative amplifier seeded by gain-switched laser diode pulses

We demonstrated the regenerative amplification of picosecond laser pulses generated by a gain-switched laser diode at 640 nm with a Pr:YLF crystal that was continuously pumped by a multimode blue laser diode. A 0.7-pJ seed pulse energy sufficiently suppressed the self-oscillation in the amplifier. The amplified pulse energy reached 33 µJ at a repetition rate of 10 kHz. The spatial beam quality was nearly TEM₀₀. We also demonstrated second- and third-harmonic generation and obtained 320- and 213-nm pulse energies of 18 and 0.83 µJ at 10 kHz.