Pr³⁺:YLF mode-locked laser at 640  nm directly pumped by InGaN-diode lasers

We attain stable mode-locking of an InGaN laser-diode-pumped Pr³⁺:YLF laser with a pump power of 2.8 W using a semiconductor saturable absorption mirror. A maximum averaged output power of 65 mW was obtained with a 45-ps pulse width at a pulse repetition rate of 108 MHz. We also attempted Kerr-lens mode-locking by employing an SF57 glass in a cavity as a Kerr medium.