High repetition rate diode-pumped self-pulsed few-cycle alexandrite laser

We reported a high repetition rate diode-pumped alexandrite femtosecond laser using a simple linear cavity. Laser emission spectrum was as broad as ∼20 nm by inserting a 0.5-mm-thick quartz birefringent plate as a spectral modulation component. Pulse duration as short as few-cycle 36 fs with the repetition rates of 2.48 GHz was measured at pump power of 17 W. To the best of our knowledge, this is the shortest pulse duration achieved in the alexandrite lasers.