Diode-pumped 640 nm Pr:YLF regenerative laser pulse amplifier

We demonstrated regenerative laser pulse amplification at 640 nm for the first time, to the best of our knowledge, with a mode-locked Pr3+-doped LiYF4 (Pr3+:YLF) oscillator as a picosecond seed pulse. A regenerative amplifier with a Pr3+:YLF crystal was continuously pumped by a multimode InGaN diode laser. At an absorbed pump power of 3.1 W, we obtained amplified pulse energy of 13 μJ at 10 kHz with an excellent spatial beam quality of M2∼1.1, demonstrated second-harmonic generation, and obtained a 320 nm pulse energy of 5.9 μJ.